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• LibPCL issues on Ubuntu 13.10

  - by user254885

  i wanted to install the Point Cloud Library but it does not work i use an ODROID board(ARM processor) Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: libpcl-all : Depends: libpcl-1.7-all but it is not going to be installed E: Unable to correct problems, you have held broken packages. by compiling v1.7 , i get these errors : /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(ptw-fcntl.o): In function `__fcntl_nocancel': /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/i386/fcntl.c:37: undefined reference to `__libc_do_syscall' /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(ptw-fcntl.o): In function `__libc_fcntl': /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/i386/fcntl.c:53: undefined reference to `__libc_do_syscall' /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/i386/fcntl.c:57: undefined reference to `__libc_do_syscall' /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(ptw-open64.o): In function `__libc_open64': /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/open64.c:41: undefined reference to `__libc_do_syscall' /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/open64.c:45: undefined reference to `__libc_do_syscall' /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(cancellation.o):/build/buildd/eglibc-2.17/nptl/cancellation.c:96: more undefined references to `__libc_do_syscall' follow collect2: error: ld returned 1 exit status make[2]: *** [bin/pcl_convert_pcd_ascii_binary] Error 1 make[1]: *** [io/tools/CMakeFiles/pcl_convert_pcd_ascii_binary.dir/all] Error 2 make: *** [all] Error 2 i could not find anything in google to solve these errors i believe some packages were not ported for ARM processors any help would be appreciated $ dpkg --list | grep headers ii linux-headers-3.0.63-odroidx2 20130215 ii linux-headers-3.0.71-odroidx2 20130415 ii linux-headers-3.0.74-odroidx2 20130417 ii linux-headers-3.0.75-odroidx2 20130426 ii linux-headers-3.1.10-6 3.1.10-6.10 ii linux-headers-3.1.10-6-ac100 3.1.10-6.10 ii linux-headers-ac100 3.1.10.6.2 installing packages did'nt do well sudo apt-get install linux-generic [sudo] password for odroid: Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: debugedit libasound2-dev libestools2.1-dev librpmbuild3 librpmsign1 thunderbird-locale-en thunderbird-locale-en-gb thunderbird-locale-en-us thunderbird-locale-ko Use 'apt-get autoremove' to remove them. The following extra packages will be installed: linux-headers-3.11.0-17 linux-headers-3.11.0-17-generic linux-headers-generic linux-image-3.11.0-17-generic linux-image-generic Suggested packages: fdutils linux-doc-3.11.0 linux-source-3.11.0 linux-tools The following NEW packages will be installed: linux-generic linux-headers-3.11.0-17 linux-headers-3.11.0-17-generic linux-headers-generic linux-image-3.11.0-17-generic linux-image-generic 0 upgraded, 6 newly installed, 0 to remove and 0 not upgraded. Need to get 58.2 MB of archives. After this operation, 203 MB of additional disk space will be used. Do you want to continue [Y/n]? y Get:1 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-image-3.11.0-17-generic armhf 3.11.0-17.31 [44.5 MB] Get:2 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-image-generic armhf 3.11.0.17.18 [2,356 B] Get:3 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-headers-3.11.0-17 all 3.11.0-17.31 [12.6 MB] Get:4 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-headers-3.11.0-17-generic armhf 3.11.0-17.31 [1,128 kB] Get:5 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-headers-generic armhf 3.11.0.17.18 [2,350 B] Get:6 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-generic armhf 3.11.0.17.18 [1,726 B] Fetched 58.2 MB in 13s (4,379 kB/s) Selecting previously unselected package linux-image-3.11.0-17-generic. (Reading database ... 258618 files and directories currently installed.) Unpacking linux-image-3.11.0-17-generic (from .../linux-image-3.11.0-17-generic_3.11.0-17.31_armhf.deb) ... Examining /etc/kernel/preinst.d/ Done. Selecting previously unselected package linux-image-generic. Unpacking linux-image-generic (from .../linux-image-generic_3.11.0.17.18_armhf.deb) ... Selecting previously unselected package linux-headers-3.11.0-17. Unpacking linux-headers-3.11.0-17 (from .../linux-headers-3.11.0-17_3.11.0-17.31_all.deb) ... Selecting previously unselected package linux-headers-3.11.0-17-generic. Unpacking linux-headers-3.11.0-17-generic (from .../linux-headers-3.11.0-17-generic_3.11.0-17.31_armhf.deb) ... Selecting previously unselected package linux-headers-generic. Unpacking linux-headers-generic (from .../linux-headers-generic_3.11.0.17.18_armhf.deb) ... Selecting previously unselected package linux-generic. Unpacking linux-generic (from .../linux-generic_3.11.0.17.18_armhf.deb) ... Setting up linux-image-3.11.0-17-generic (3.11.0-17.31) ... Running depmod. update-initramfs: deferring update (hook will be called later) cp: cannot stat ‘/boot/initrd.img-3.11.0-17-generic’: No such file or directory Failed to copy /boot/initrd.img-3.11.0-17-generic to /boot/initrd.img at /var/lib/dpkg/info/linux-image-3.11.0-17-generic.postinst line 730. dpkg: error processing linux-image-3.11.0-17-generic (--configure): subprocess installed post-installation script returned error exit status 2 dpkg: dependency problems prevent configuration of linux-image-generic: linux-image-generic depends on linux-image-3.11.0-17-generic; however: Package linux-image-3.11.0-17-generic is not configured yet. dpkg: error processing linux-image-generic (--configure): dependency problems - leaving unconfigured Setting up linux-headers-3.11.0-17 (3.11.0-17.31) ... No apport report written because MaxReports is reached already No apport report written because MaxReports is reached already Setting up linux-headers-3.11.0-17-generic (3.11.0-17.31) ... Examining /etc/kernel/header_postinst.d. Setting up linux-headers-generic (3.11.0.17.18) ... dpkg: dependency problems prevent configuration of linux-generic: linux-generic depends on linux-image-generic (= 3.11.0.17.18); however: Package linux-image-generic is not configured yet. dpkg: error processing linux-generic (--configure): dependency problems - leaving unconfigured No apport report written because MaxReports is reached already Errors were encountered while processing: linux-image-3.11.0-17-generic linux-image-generic linux-generic E: Sub-process /usr/bin/dpkg returned an error code (1) i had to uninstall these cos they were messing up other packages installation(buildessentials were already installed)

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• SSAO Distortion

  - by Robert Xu

  I'm currently (attempting) to add SSAO to my engine, except it's...not really work, to say the least. I use a deferred renderer to render my scene. I have four render targets: Albedo, Light, Normal, and Depth. Here are the parameters for all of them (Surface Format, Depth Format): Albedo: 32-bit ARGB, Depth24Stencil8 Light: 32-bit ARGB, None Normal: 32-bit ARGB, None Depth: 8-bit R (Single), Depth24Stencil8 To generate my random noise map for the SSAO, I do the following for each pixel in the noise map: Vector3 v3 = Vector3.Zero; double z = rand.NextDouble() * 2.0 - 1.0; double r = Math.Sqrt(1.0 - z * z); double angle = rand.NextDouble() * MathHelper.TwoPi; v3.X = (float)(r * Math.Cos(angle)); v3.Y = (float)(r * Math.Sin(angle)); v3.Z = (float)z; v3 += offset; v3 *= 0.5f; result[i] = new Color(v3); This is my GBuffer rendering effect: PixelInput RenderGBufferColorVertexShader(VertexInput input) { PixelInput pi = ( PixelInput ) 0; pi.Position = mul(input.Position, WorldViewProjection); pi.Normal = mul(input.Normal, WorldInverseTranspose); pi.Color = input.Color; pi.TPosition = pi.Position; pi.WPosition = input.Position; return pi; } GBufferTarget RenderGBufferColorPixelShader(PixelInput input) { GBufferTarget output = ( GBufferTarget ) 0; float3 position = input.TPosition.xyz / input.TPosition.w; output.Albedo = lerp(float4(1.0f, 1.0f, 1.0f, 1.0f), input.Color, ColorFactor); output.Normal = EncodeNormal(input.Normal); output.Depth = position.z; return output; } And here is the SSAO effect: float4 EncodeNormal(float3 normal) { return float4((normal.xyz * 0.5f) + 0.5f, 0.0f); } float3 DecodeNormal(float4 encoded) { return encoded * 2.0 - 1.0f; } float Intensity; float Size; float2 NoiseOffset; float4x4 ViewProjection; float4x4 ViewProjectionInverse; texture DepthMap; texture NormalMap; texture RandomMap; const float3 samples[16] = { float3(0.01537562, 0.01389096, 0.02276565), float3(-0.0332658, -0.2151698, -0.0660736), float3(-0.06420016, -0.1919067, 0.5329634), float3(-0.05896204, -0.04509097, -0.03611697), float3(-0.1302175, 0.01034653, 0.01543675), float3(0.3168565, -0.182557, -0.01421785), float3(-0.02134448, -0.1056605, 0.00576055), float3(-0.3502164, 0.281433, -0.2245609), float3(-0.00123525, 0.00151868, 0.02614773), float3(0.1814744, 0.05798516, -0.02362876), float3(0.07945167, -0.08302628, 0.4423518), float3(0.321987, -0.05670302, -0.05418307), float3(-0.00165138, -0.00410309, 0.00537362), float3(0.01687791, 0.03189049, -0.04060405), float3(-0.04335613, -0.00530749, 0.06443053), float3(0.8474263, -0.3590308, -0.02318038), }; sampler DepthSampler = sampler_state { Texture = DepthMap; MipFilter = Point; MinFilter = Point; MagFilter = Point; AddressU = Clamp; AddressV = Clamp; AddressW = Clamp; }; sampler NormalSampler = sampler_state { Texture = NormalMap; MipFilter = Linear; MinFilter = Linear; MagFilter = Linear; AddressU = Clamp; AddressV = Clamp; AddressW = Clamp; }; sampler RandomSampler = sampler_state { Texture = RandomMap; MipFilter = Linear; MinFilter = Linear; MagFilter = Linear; }; struct VertexInput { float4 Position : POSITION0; float2 TextureCoordinates : TEXCOORD0; }; struct PixelInput { float4 Position : POSITION0; float2 TextureCoordinates : TEXCOORD0; }; PixelInput SSAOVertexShader(VertexInput input) { PixelInput pi = ( PixelInput ) 0; pi.Position = input.Position; pi.TextureCoordinates = input.TextureCoordinates; return pi; } float3 GetXYZ(float2 uv) { float depth = tex2D(DepthSampler, uv); float2 xy = uv * 2.0f - 1.0f; xy.y *= -1; float4 p = float4(xy, depth, 1); float4 q = mul(p, ViewProjectionInverse); return q.xyz / q.w; } float3 GetNormal(float2 uv) { return DecodeNormal(tex2D(NormalSampler, uv)); } float4 SSAOPixelShader(PixelInput input) : COLOR0 { float depth = tex2D(DepthSampler, input.TextureCoordinates); float3 position = GetXYZ(input.TextureCoordinates); float3 normal = GetNormal(input.TextureCoordinates); float occlusion = 1.0f; float3 reflectionRay = DecodeNormal(tex2D(RandomSampler, input.TextureCoordinates + NoiseOffset)); for (int i = 0; i < 16; i++) { float3 sampleXYZ = position + reflect(samples[i], reflectionRay) * Size; float4 screenXYZW = mul(float4(sampleXYZ, 1.0f), ViewProjection); float3 screenXYZ = screenXYZW.xyz / screenXYZW.w; float2 sampleUV = float2(screenXYZ.x * 0.5f + 0.5f, 1.0f - (screenXYZ.y * 0.5f + 0.5f)); float frontMostDepthAtSample = tex2D(DepthSampler, sampleUV); if (frontMostDepthAtSample < screenXYZ.z) { occlusion -= 1.0f / 16.0f; } } return float4(occlusion * Intensity * float3(1.0, 1.0, 1.0), 1.0); } technique SSAO { pass Pass0 { VertexShader = compile vs_3_0 SSAOVertexShader(); PixelShader = compile ps_3_0 SSAOPixelShader(); } } However, when I use the effect, I get some pretty bad distortion: Here's the light map that goes with it -- is the static-like effect supposed to be like that? I've noticed that even if I'm looking at nothing, I still get the static-like effect. (you can see it in the screenshot; the top half doesn't have any geometry yet it still has the static-like effect) Also, does anyone have any advice on how to effectively debug shaders?

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• My raycaster is putting out strange results, how do I fix it?

  - by JamesK89

  I'm working on a raycaster in ActionScript 3.0 for the fun of it, and as a learning experience. I've got it up and running and its displaying me output as expected however I'm getting this strange bug where rays go through corners of blocks and the edges of blocks appear through walls. Maybe somebody with more experience can point out what I'm doing wrong or maybe a fresh pair of eyes can spot a tiny bug I haven't noticed. Thank you so much for your help! Screenshots: http://i55.tinypic.com/25koebm.jpg http://i51.tinypic.com/zx5jq9.jpg Relevant code: function drawScene() { rays.graphics.clear(); rays.graphics.lineStyle(1, rgba(0x00,0x66,0x00)); var halfFov = (player.fov/2); var numRays:int = ( stage.stageWidth / COLUMN_SIZE ); var prjDist = ( stage.stageWidth / 2 ) / Math.tan(toRad( halfFov )); var angStep = ( player.fov / numRays ); for( var i:int = 0; i < numRays; i++ ) { var rAng = ( ( player.angle - halfFov ) + ( angStep * i ) ) % 360; if( rAng < 0 ) rAng += 360; var ray:Object = castRay(player.position, rAng); drawRaySlice(i*COLUMN_SIZE, prjDist, player.angle, ray); } } function drawRaySlice(sx:int, prjDist, angle, ray:Object) { if( ray.distance >= MAX_DIST ) return; var height:int = int(( TILE_SIZE / (ray.distance * Math.cos(toRad(angle-ray.angle))) ) * prjDist); if( !height ) return; var yTop = int(( stage.stageHeight / 2 ) - ( height / 2 )); if( yTop < 0 ) yTop = 0; var yBot = int(( stage.stageHeight / 2 ) + ( height / 2 )); if( yBot > stage.stageHeight ) yBot = stage.stageHeight; rays.graphics.moveTo( (ray.origin.x / TILE_SIZE) * MINI_SIZE, (ray.origin.y / TILE_SIZE) * MINI_SIZE ); rays.graphics.lineTo( (ray.hit.x / TILE_SIZE) * MINI_SIZE, (ray.hit.y / TILE_SIZE) * MINI_SIZE ); for( var x:int = 0; x < COLUMN_SIZE; x++ ) { for( var y:int = yTop; y < yBot; y++ ) { buffer.setPixel(sx+x, y, clrTable[ray.tile-1] >> ( ray.horz ? 1 : 0 )); } } } function castRay(origin:Point, angle):Object { // Return values var rTexel = 0; var rHorz = false; var rTile = 0; var rDist = MAX_DIST + 1; var rMap:Point = new Point(); var rHit:Point = new Point(); // Ray angle and slope var ra = toRad(angle) % ANGLE_360; if( ra < ANGLE_0 ) ra += ANGLE_360; var rs = Math.tan(ra); var rUp = ( ra > ANGLE_0 && ra < ANGLE_180 ); var rRight = ( ra < ANGLE_90 || ra > ANGLE_270 ); // Ray position var rx = 0; var ry = 0; // Ray step values var xa = 0; var ya = 0; // Ray position, in map coordinates var mx:int = 0; var my:int = 0; var mt:int = 0; // Distance var dx = 0; var dy = 0; var ds = MAX_DIST + 1; // Horizontal intersection if( ra != ANGLE_180 && ra != ANGLE_0 && ra != ANGLE_360 ) { ya = ( rUp ? TILE_SIZE : -TILE_SIZE ); xa = ya / rs; ry = int( origin.y / TILE_SIZE ) * ( TILE_SIZE ) + ( rUp ? TILE_SIZE : -1 ); rx = origin.x + ( ry - origin.y ) / rs; mx = 0; my = 0; while( mx >= 0 && my >= 0 && mx < world.size.x && my < world.size.y ) { mx = int( rx / TILE_SIZE ); my = int( ry / TILE_SIZE ); mt = getMapTile(mx,my); if( mt > 0 && mt < 9 ) { dx = rx - origin.x; dy = ry - origin.y; ds = ( dx * dx ) + ( dy * dy ); if( rDist >= MAX_DIST || ds < rDist ) { rDist = ds; rTile = mt; rMap.x = mx; rMap.y = my; rHit.x = rx; rHit.y = ry; rHorz = true; rTexel = int(rx % TILE_SIZE) } break; } rx += xa; ry += ya; } } // Vertical intersection if( ra != ANGLE_90 && ra != ANGLE_270 ) { xa = ( rRight ? TILE_SIZE : -TILE_SIZE ); ya = xa * rs; rx = int( origin.x / TILE_SIZE ) * ( TILE_SIZE ) + ( rRight ? TILE_SIZE : -1 ); ry = origin.y + ( rx - origin.x ) * rs; mx = 0; my = 0; while( mx >= 0 && my >= 0 && mx < world.size.x && my < world.size.y ) { mx = int( rx / TILE_SIZE ); my = int( ry / TILE_SIZE ); mt = getMapTile(mx,my); if( mt > 0 && mt < 9 ) { dx = rx - origin.x; dy = ry - origin.y; ds = ( dx * dx ) + ( dy * dy ); if( rDist >= MAX_DIST || ds < rDist ) { rDist = ds; rTile = mt; rMap.x = mx; rMap.y = my; rHit.x = rx; rHit.y = ry; rHorz = false; rTexel = int(ry % TILE_SIZE); } break; } rx += xa; ry += ya; } } return { angle: angle, distance: Math.sqrt(rDist), hit: rHit, map: rMap, tile: rTile, horz: rHorz, origin: origin, texel: rTexel }; }

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• Java collision detection and player movement: tips

  - by Loris

  I have read a short guide for game develompent (java, without external libraries). I'm facing with collision detection and player (and bullets) movements. Now i put the code. Most of it is taken from the guide (should i link this guide?). I'm just trying to expand and complete it. This is the class that take care of updates movements and firing mechanism (and collision detection): public class ArenaController { private Arena arena; /** selected cell for movement */ private float targetX, targetY; /** true if droid is moving */ private boolean moving = false; /** true if droid is shooting to enemy */ private boolean shooting = false; private DroidController droidController; public ArenaController(Arena arena) { this.arena = arena; this.droidController = new DroidController(arena); } public void update(float delta) { Droid droid = arena.getDroid(); //droid movements if (moving) { droidController.moveDroid(delta, targetX, targetY); //check if arrived if (droid.getX() == targetX && droid.getY() == targetY) moving = false; } //firing mechanism if(shooting) { //stop shot if there aren't bullets if(arena.getBullets().isEmpty()) { shooting = false; } for(int i = 0; i < arena.getBullets().size(); i++) { //current bullet Bullet bullet = arena.getBullets().get(i); System.out.println(bullet.getBounds()); //angle calculation double angle = Math.atan2(bullet.getEnemyY() - bullet.getY(), bullet.getEnemyX() - bullet.getX()); //increments x and y bullet.setX((float) (bullet.getX() + (Math.cos(angle) * bullet.getSpeed() * delta))); bullet.setY((float) (bullet.getY() + (Math.sin(angle) * bullet.getSpeed() * delta))); //collision with obstacles for(int j = 0; j < arena.getObstacles().size(); j++) { Obstacle obs = arena.getObstacles().get(j); if(bullet.getBounds().intersects(obs.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } //collisions with enemies for(int j = 0; j < arena.getEnemies().size(); j++) { Enemy ene = arena.getEnemies().get(j); if(bullet.getBounds().intersects(ene.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } } } } public boolean onClick(int x, int y) { //click on empty cell if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] == null) { //coordinates targetX = x / Arena.TILE; targetY = y / Arena.TILE; //enables movement moving = true; return true; } //click on enemy: fire if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] instanceof Enemy) { //coordinates float enemyX = x / Arena.TILE; float enemyY = y / Arena.TILE; //new bullet Bullet bullet = new Bullet(); //start coordinates bullet.setX(arena.getDroid().getX()); bullet.setY(arena.getDroid().getY()); //end coordinates (enemie) bullet.setEnemyX(enemyX); bullet.setEnemyY(enemyY); //adds bullet to arena arena.addBullet(bullet); //enables shooting shooting = true; return true; } return false; } As you can see for collision detection i'm trying to use Rectangle object. Droid example: import java.awt.geom.Rectangle2D; public class Droid { private float x; private float y; private float speed = 20f; private float rotation = 0f; private float damage = 2f; public static final int DIAMETER = 32; private Rectangle2D rectangle; public Droid() { rectangle = new Rectangle2D.Float(x, y, DIAMETER, DIAMETER); } public float getX() { return x; } public void setX(float x) { this.x = x; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getY() { return y; } public void setY(float y) { this.y = y; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getSpeed() { return speed; } public void setSpeed(float speed) { this.speed = speed; } public float getRotation() { return rotation; } public void setRotation(float rotation) { this.rotation = rotation; } public float getDamage() { return damage; } public void setDamage(float damage) { this.damage = damage; } public Rectangle2D getRectangle() { return rectangle; } } For now, if i start the application and i try to shot to an enemy, is immediately detected a collision and the bullet is removed! Can you help me with this? If the bullet hit an enemy or an obstacle in his way, it must disappear. Ps: i know that the movements of the bullets should be managed in another class. This code is temporary. update I realized what happens, but not why. With those for loops (which checks collisions) the movements of the bullets are instantaneous instead of gradual. In addition to this, if i add the collision detection to the Droid, the method intersects returns true ALWAYS while the droid is moving! public void moveDroid(float delta, float x, float y) { Droid droid = arena.getDroid(); int bearing = 1; if (droid.getX() > x) { bearing = -1; } if (droid.getX() != x) { droid.setX(droid.getX() + bearing * droid.getSpeed() * delta); //obstacles collision detection for(Obstacle obs : arena.getObstacles()) { if(obs.getRectangle().intersects(droid.getRectangle())) { System.out.println("Collision detected"); //ALWAYS HERE } } //controlla se è arrivato if ((droid.getX() < x && bearing == -1) || (droid.getX() > x && bearing == 1)) droid.setX(x); } bearing = 1; if (droid.getY() > y) { bearing = -1; } if (droid.getY() != y) { droid.setY(droid.getY() + bearing * droid.getSpeed() * delta); if ((droid.getY() < y && bearing == -1) || (droid.getY() > y && bearing == 1)) droid.setY(y); } }

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• Super constructor must be a first statement in Java constructor [closed]

  - by Val

  I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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• How to implement smooth flocking

  - by Craig

  I'm working on a simple survival game, avoid the big guy and chase the the small guys to stay alive for as long as possible. I have taken the chase and evade example from MSDN create and drawn 20 mice on the screen. I want the small guys to flock when they arent evading. They are doing this, but it isnt as smooth as I would like it to be. How do i make the movement smoother? Its very jittery.# Below is what I have going at the moment, flocking code is within the IF statement, when it isnt set to evading. Any help would be greatly appreciated! :) namespace ChaseAndEvade { class MouseSprite { public enum MouseAiState { // evading the cat Evading, // the mouse can't see the "cat", and it's wandering around. Wander } // how fast can the mouse move? public float MaxMouseSpeed = 4.5f; // and how fast can it turn? public float MouseTurnSpeed = 0.20f; // MouseEvadeDistance controls the distance at which the mouse will flee from // cat. If the mouse is further than "MouseEvadeDistance" pixels away, he will // consider himself safe. public float MouseEvadeDistance = 100.0f; // this constant is similar to TankHysteresis. The value is larger than the // tank's hysteresis value because the mouse is faster than the tank: with a // higher velocity, small fluctuations are much more visible. public float MouseHysteresis = 60.0f; public Texture2D mouseTexture; public Vector2 mouseTextureCenter; public Vector2 mousePosition; public MouseAiState mouseState = MouseAiState.Wander; public float mouseOrientation; public Vector2 mouseWanderDirection; int separationImpact = 4; int cohesionImpact = 6; int alignmentImpact = 2; int sensorDistance = 50; public void UpdateMouse(Vector2 position, MouseSprite [] mice, int numberMice, int index) { Vector2 catPosition = position; int enemies = numberMice; // first, calculate how far away the mouse is from the cat, and use that // information to decide how to behave. If they are too close, the mouse // will switch to "active" mode - fleeing. if they are far apart, the mouse // will switch to "idle" mode, where it roams around the screen. // we use a hysteresis constant in the decision making process, as described // in the accompanying doc file. float distanceFromCat = Vector2.Distance(mousePosition, catPosition); // the cat is a safe distance away, so the mouse should idle: if (distanceFromCat > MouseEvadeDistance + MouseHysteresis) { mouseState = MouseAiState.Wander; } // the cat is too close; the mouse should run: else if (distanceFromCat < MouseEvadeDistance - MouseHysteresis) { mouseState = MouseAiState.Evading; } // if neither of those if blocks hit, we are in the "hysteresis" range, // and the mouse will continue doing whatever it is doing now. // the mouse will move at a different speed depending on what state it // is in. when idle it won't move at full speed, but when actively evading // it will move as fast as it can. this variable is used to track which // speed the mouse should be moving. float currentMouseSpeed; // the second step of the Update is to change the mouse's orientation based // on its current state. if (mouseState == MouseAiState.Evading) { // If the mouse is "active," it is trying to evade the cat. The evasion // behavior is accomplished by using the TurnToFace function to turn // towards a point on a straight line facing away from the cat. In other // words, if the cat is point A, and the mouse is point B, the "seek // point" is C. // C // B // A Vector2 seekPosition = 2 * mousePosition - catPosition; // Use the TurnToFace function, which we introduced in the AI Series 1: // Aiming sample, to turn the mouse towards the seekPosition. Now when // the mouse moves forward, it'll be trying to move in a straight line // away from the cat. mouseOrientation = ChaseAndEvadeGame.TurnToFace(mousePosition, seekPosition, mouseOrientation, MouseTurnSpeed); // set currentMouseSpeed to MaxMouseSpeed - the mouse should run as fast // as it can. currentMouseSpeed = MaxMouseSpeed; } else { // if the mouse isn't trying to evade the cat, it should just meander // around the screen. we'll use the Wander function, which the mouse and // tank share, to accomplish this. mouseWanderDirection and // mouseOrientation are passed by ref so that the wander function can // modify them. for more information on ref parameters, see // http://msdn2.microsoft.com/en-us/library/14akc2c7(VS.80).aspx ChaseAndEvadeGame.Wander(mousePosition, ref mouseWanderDirection, ref mouseOrientation, MouseTurnSpeed); // if the mouse is wandering, it should only move at 25% of its maximum // speed. currentMouseSpeed = .25f * MaxMouseSpeed; Vector2 separate = Vector2.Zero; Vector2 moveCloser = Vector2.Zero; Vector2 moveAligned = Vector2.Zero; // What the AI does when it sees other AIs for (int j = 0; j < enemies; j++) { if (index != j) { // Calculate a vector towards another AI Vector2 separation = mice[index].mousePosition - mice[j].mousePosition; // Only react if other AI is within a certain distance if ((separation.Length() < this.sensorDistance) & (separation.Length()> 0) ) { moveAligned += mice[j].mouseWanderDirection; float distance = Math.Abs(separation.Length()); if (distance == 0) distance = 1; moveCloser += mice[j].mousePosition; separation.Normalize(); separate += separation / distance; } } } if (moveAligned.LengthSquared() != 0) { moveAligned.Normalize(); } if (moveCloser.LengthSquared() != 0) { moveCloser.Normalize(); } moveCloser /= enemies; mice[index].mousePosition += (separate * separationImpact) + (moveCloser * cohesionImpact) + (moveAligned * alignmentImpact); } // The final step is to move the mouse forward based on its current // orientation. First, we construct a "heading" vector from the orientation // angle. To do this, we'll use Cosine and Sine to tell us the x and y // components of the heading vector. See the accompanying doc for more // information. Vector2 heading = new Vector2( (float)Math.Cos(mouseOrientation), (float)Math.Sin(mouseOrientation)); // by multiplying the heading and speed, we can get a velocity vector. the // velocity vector is then added to the mouse's current position, moving him // forward. mousePosition += heading * currentMouseSpeed; } } }

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• C# 2D Camera Max Zoom

  - by Craig

  I have a simple ship sprite moving around the screen along with a 2D Camera. I have zooming in and out working, however when I zoom out it goes past the world bounds and has the cornflower blue background showing. How do I sort it that I can only zoom out as far as showing the entire world (which is a picture of OZ) and thats it? I dont want any of the cornflower blue showing. Cheers! namespace GamesCoursework_1 { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; // player variables Texture2D Ship; Vector2 Ship_Position; float Ship_Rotation = 0.0f; Vector2 Ship_Origin; Vector2 Ship_Velocity; const float tangentialVelocity = 4f; float friction = 0.05f; static Point CameraViewport = new Point(800, 800); Camera2d cam = new Camera2d((int)CameraViewport.X, (int)CameraViewport.Y); //Size of world static Point worldSize = new Point(1600, 1600); // Screen variables static Point worldCenter = new Point(worldSize.X / 2, worldSize.Y / 2); Rectangle playerBounds = new Rectangle(CameraViewport.X / 2, CameraViewport.Y / 2, worldSize.X - CameraViewport.X, worldSize.Y - CameraViewport.Y); Rectangle worldBounds = new Rectangle(0, 0, worldSize.X, worldSize.Y); Texture2D background; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = CameraViewport.X; graphics.PreferredBackBufferHeight = CameraViewport.Y; Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); // TODO: use this.Content to load your game content here Ship = Content.Load<Texture2D>("Ship"); Ship_Origin.X = Ship.Width / 2; Ship_Origin.Y = Ship.Height / 2; background = Content.Load<Texture2D>("aus"); Ship_Position = new Vector2(worldCenter.X, worldCenter.Y); cam.Pos = Ship_Position; cam.Zoom = 1f; } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { // TODO: Unload any non ContentManager content here } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // TODO: Add your update logic here Ship_Position = Ship_Velocity + Ship_Position; keyPressed(); base.Update(gameTime); } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // TODO: Add your drawing code here spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend, null, null, null,null, cam.get_transformation(GraphicsDevice)); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.Draw(Ship, Ship_Position, Ship.Bounds, Color.White, Ship_Rotation, Ship_Origin, 1.0f, SpriteEffects.None, 0f); spriteBatch.End(); base.Draw(gameTime); } private void Ship_Move(Vector2 move) { Ship_Position += move; } private void keyPressed() { KeyboardState keyState; // Move right keyState = Keyboard.GetState(); if (keyState.IsKeyDown(Keys.Right)) { Ship_Rotation = Ship_Rotation + 0.1f; } if (keyState.IsKeyDown(Keys.Left)) { Ship_Rotation = Ship_Rotation - 0.1f; } if (keyState.IsKeyDown(Keys.Up)) { Ship_Velocity.X = (float)Math.Cos(Ship_Rotation) * tangentialVelocity; Ship_Velocity.Y = (float)Math.Sin(Ship_Rotation) * tangentialVelocity; if ((int)Ship_Position.Y < playerBounds.Bottom && (int)Ship_Position.Y > playerBounds.Top) cam._pos.Y = Ship_Position.Y; if ((int)Ship_Position.X > playerBounds.Left && (int)Ship_Position.X < playerBounds.Right) cam._pos.X = Ship_Position.X; Ship_Position += new Vector2(tangentialVelocity, 0); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(-tangentialVelocity, 0.0f); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(-tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(0.0f, -tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, -tangentialVelocity * 2); Ship_Position += new Vector2(0.0f, tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, 2 * tangentialVelocity); } else if(Ship_Velocity != Vector2.Zero) { float i = Ship_Velocity.X; float j = Ship_Velocity.Y; Ship_Velocity.X = i -= friction * i; Ship_Velocity.Y = j -= friction * j; if ((int)Ship_Position.Y < playerBounds.Bottom && (int)Ship_Position.Y > playerBounds.Top) cam._pos.Y = Ship_Position.Y; if ((int)Ship_Position.X > playerBounds.Left && (int)Ship_Position.X < playerBounds.Right) cam._pos.X = Ship_Position.X; Ship_Position += new Vector2(tangentialVelocity, 0); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(-tangentialVelocity, 0.0f); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(-tangentialVelocity * 2, 0.0f); Ship_Position += new Vector2(0.0f, -tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, -tangentialVelocity * 2); Ship_Position += new Vector2(0.0f, tangentialVelocity); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, 2 * tangentialVelocity); } if (keyState.IsKeyDown(Keys.Q)) { if (cam.Zoom < 2f) cam.Zoom += 0.05f; } if (keyState.IsKeyDown(Keys.A)) { if (cam.Zoom > 0.3f) cam.Zoom -= 0.05f; } } } }

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• Libgdx - 2D Mesh rendering overlap glitch

  - by user46858

  I am trying to render a 2D circle segment mesh (quarter circle)using Libgdx/Opengl ES 2.0 but I seem to be getting an overlapping issue as seen in the picture attached. I cant seem to find the cause of the problem but the overlapping disappears/reappears if I drag and resize the window to random sizes. The problem occurs on both pc and android. The strange thing is the first two segments atleast dont seem to be causing any overlapping only the third and/or forth segment.......even though they are all rendered using the same mesh object..... I have spent ages trying to find the cause of the problem before posting here for help so ANY help/advice in finding the cause of this problem would be really appreciated. public class MyGdxGame extends Game { private SpriteBatch batch; private Texture texture; private OrthographicCamera myCamera; private float w; private float h; private ShaderProgram circleSegShader; private Mesh circleScaleSegMesh; private Stage stage; private float TotalSegments; Vector3 virtualres; @Override public void create() { w = Gdx.graphics.getWidth(); h = Gdx.graphics.getHeight(); batch = new SpriteBatch(); ViewPortsize = new Vector2(); TotalSegments = 4.0f; virtualres = new Vector3(1280.0f, 720.0f, 0.0f); myCamera = new OrthographicCamera(); myCamera.setToOrtho(false, w, h); texture = new Texture(Gdx.files.internal("data/libgdx.png")); texture.setFilter(TextureFilter.Linear, TextureFilter.Linear); circleScaleSegMesh = createCircleMesh_V3(0.0f,0.0f,200.0f, 30.0f,3, (360.0f /TotalSegments) ); circleSegShader = loadShaderFromFile(new String("circleseg.vert"), new String("circleseg.frag")); shaderProgram.pedantic = false; stage = new Stage(); stage.setViewport(new ExtendViewport(w, h)); Gdx.input.setInputProcessor(stage); } @Override public void render() { .... //render renderInit(); renderCircleScaledSegment(); } @Override public void resize(int width, int height) { stage.getViewport().update(width, height, true); myCamera.position.set( virtualres.x/2.0f, virtualres.y/2.0f, 0.0f); myCamera.update(); } public void renderInit(){ Gdx.gl20.glClearColor(1.0f, 1.0f, 1.0f, 0.0f); Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT); batch.setShader(null); batch.setProjectionMatrix(myCamera.combined); } public void renderCircleScaledSegment(){ Gdx.gl20.glEnable(GL20.GL_DEPTH_TEST); Gdx.gl20.glBlendFunc(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA); Gdx.gl20.glEnable(GL20.GL_BLEND); batch.begin(); circleSegShader.begin(); Matrix4 modelMatrix = new Matrix4(); Matrix4 cameraMatrix = new Matrix4(); Matrix4 cameraMatrix2 = new Matrix4(); Matrix4 cameraMatrix3 = new Matrix4(); Matrix4 cameraMatrix4 = new Matrix4(); cameraMatrix = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f), 0.0f - ((360.0f /TotalSegments)/ 2.0f)).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix.mul(modelMatrix); cameraMatrix2 = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f), 0.0f - ((360.0f /TotalSegments)/ 2.0f) +(360.0f /TotalSegments) ).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix2.mul(modelMatrix); cameraMatrix3 = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f), 0.0f - ((360.0f /TotalSegments)/ 2.0f) +(2*(360.0f /TotalSegments))).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix3.mul(modelMatrix); cameraMatrix4 = myCamera.combined.cpy(); modelMatrix.idt().rotate(new Vector3(0.0f,0.0f,1.0f),0.0f - ((360.0f /TotalSegments)/ 2.0f) +(3*(360.0f /TotalSegments)) ).trn(virtualres.x/2.0f,virtualres.y/2.0f, 0.0f); cameraMatrix4.mul(modelMatrix); Vector3 box2dpos = new Vector3(0.0f, 0.0f, 0.0f); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix2); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix3); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.setUniformMatrix("u_projTrans", cameraMatrix4); circleSegShader.setUniformf("u_box2dpos", box2dpos); circleSegShader.setUniformi("u_texture", 0); texture.bind(); circleScaleSegMesh.render(circleSegShader, GL20.GL_TRIANGLES); circleSegShader.end(); batch.flush(); batch.end(); Gdx.gl20.glDisable(GL20.GL_DEPTH_TEST); Gdx.gl20.glDisable(GL20.GL_BLEND); } public Mesh createCircleMesh_V3(float cx, float cy, float r_out, float r_in, int num_segments, float segmentSizeDegrees){ float theta = (float) (2.0f * MathUtils.PI / (num_segments * (360.0f / segmentSizeDegrees))); float c = MathUtils.cos(theta);//precalculate the sine and cosine float s = MathUtils.sin(theta); float t,t2; float x = r_out;//we start at angle = 0 float y = 0; float x2 = r_in;//we start at angle = 0 float y2 = 0; float[] meshCoords = new float[num_segments *2 *3 *7]; int arrayIndex = 0; //array for triangles without indices for(int ii = 0; ii < num_segments; ii++) { meshCoords[arrayIndex] = x2+cx; meshCoords[arrayIndex +1] = y2+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; meshCoords[arrayIndex] = x+cx; meshCoords[arrayIndex +1] = y+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; t = x; x = c * x - s * y; y = s * t + c * y; meshCoords[arrayIndex] = x+cx; meshCoords[arrayIndex +1] = y+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; meshCoords[arrayIndex] = x2+cx; meshCoords[arrayIndex +1] = y2+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; meshCoords[arrayIndex] = x+cx; meshCoords[arrayIndex +1] = y+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; t2 = x2; x2 = c * x2 - s * y2; y2 = s * t2 + c * y2; meshCoords[arrayIndex] = x2+cx; meshCoords[arrayIndex +1] = y2+cy; meshCoords[arrayIndex +2] = 0.0f; meshCoords[arrayIndex +3] = 63.0f/255.0f; meshCoords[arrayIndex +4] = 139.0f/255.0f; meshCoords[arrayIndex +5] = 217.0f/255.0f; meshCoords[arrayIndex +6] = 0.7f; arrayIndex = arrayIndex + 7; } Mesh myMesh = new Mesh(VertexDataType.VertexArray, false, meshCoords.length, 0, new VertexAttribute(VertexAttributes.Usage.Position, 3, "a_position"), new VertexAttribute(VertexAttributes.Usage.Color, 4, "a_color")); myMesh.setVertices(meshCoords); return myMesh; } }

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• Adding objects to the environment at timed intervals

  - by david

  I am using an ArrayList to handle objects and at each interval of 120 frames, I am adding a new object of the same type at a random location along the z-axis of 60. The problem is, it doesn't add just 1. It depends on how many are in the list. If I kill the Fox before the time interval when one is supposed to spawn comes, then no Fox will be spawned. If I don't kill any foxes, it grows exponentially. I only want one Fox to be added every 120 frames. This problem never happened before when I created new ones and added them to the environment. Any insights? Here is my code: /**** FOX CLASS ****/ import env3d.EnvObject; import java.util.ArrayList; public class Fox extends Creature { private int frame = 0; public Fox(double x, double y, double z) { super(x, y, z); // Must use the mutator as the fields have private access // in the parent class setTexture("models/fox/fox.png"); setModel("models/fox/fox.obj"); setScale(1.4); } public void move(ArrayList<Creature> creatures, ArrayList<Creature> dead_creatures, ArrayList<Creature> new_creatures) { frame++; setX(getX()-0.2); setRotateY(270); if (frame > 120) { Fox f = new Fox(60, 1, (int)(Math.random()*28)+1); new_creatures.add(f); frame = 0; } for (Creature c : creatures) { if (this.distance(c) < this.getScale()+c.getScale() && c instanceof Tux) { dead_creatures.add(c); } } for (Creature c : creatures) { if (c.getX() < 1 && c instanceof Fox) { dead_creatures.add(c); } } } } import env3d.Env; import java.util.ArrayList; import org.lwjgl.input.Keyboard; /** * A predator and prey simulation. Fox is the predator and Tux is the prey. */ public class Game { private Env env; private boolean finished; private ArrayList<Creature> creatures; private KingTux king; private Snowball ball; private int tuxcounter; private int kills; /** * Constructor for the Game class. It sets up the foxes and tuxes. */ public Game() { // we use a separate ArrayList to keep track of each animal. // our room is 50 x 50. creatures = new ArrayList<Creature>(); for (int i = 0; i < 10; i++) { creatures.add(new Tux((int)(Math.random()*10)+1, 1, (int)(Math.random()*28)+1)); } for (int i = 0; i < 1; i++) { creatures.add(new Fox(60, 1, (int)(Math.random()*28)+1)); } king = new KingTux(25, 1, 35); ball = new Snowball(-400, -400, -400); } /** * Play the game */ public void play() { finished = false; // Create the new environment. Must be done in the same // method as the game loop env = new Env(); // Make the room 50 x 50. env.setRoom(new Room()); // Add all the animals into to the environment for display for (Creature c : creatures) { env.addObject(c); } for (Creature c : creatures) { if (c instanceof Tux) { tuxcounter++; } } env.addObject(king); env.addObject(ball); // Sets up the camera env.setCameraXYZ(30, 50, 55); env.setCameraPitch(-63); // Turn off the default controls env.setDefaultControl(false); // A list to keep track of dead tuxes. ArrayList<Creature> dead_creatures = new ArrayList<Creature>(); ArrayList<Creature> new_creatures = new ArrayList<Creature>(); // The main game loop while (!finished) { if (env.getKey() == 1 || tuxcounter == 0) { finished = true; } env.setDisplayStr("Tuxes: " + tuxcounter, 15, 0); env.setDisplayStr("Kills: " + kills, 140, 0); processInput(); ball.move(); king.check(); // Move each fox and tux. for (Creature c : creatures) { c.move(creatures, dead_creatures, new_creatures); } for (Creature c : creatures) { if (c.distance(ball) < c.getScale()+ball.getScale() && c instanceof Fox) { dead_creatures.add(c); ball.setX(-400); ball.setY(-400); ball.setZ(-400); kills++; } } // Clean up of the dead tuxes. for (Creature c : dead_creatures) { if (c instanceof Tux) { tuxcounter--; } env.removeObject(c); creatures.remove(c); } for (Creature c : new_creatures) { creatures.add(c); env.addObject(c); } // we clear the ArrayList for the next loop. We could create a new one // every loop but that would be very inefficient. dead_creatures.clear(); new_creatures.clear(); // Update display env.advanceOneFrame(); } // Just a little clean up env.exit(); } private void processInput() { int keyDown = env.getKeyDown(); int key = env.getKey(); if (keyDown == 203) { king.setX(king.getX()-1); } else if (keyDown == 205) { king.setX(king.getX()+1); } if (ball.getX() <= -400 && key == Keyboard.KEY_S) { ball.setX(king.getX()); ball.setY(king.getY()); ball.setZ(king.getZ()); } } /** * Main method to launch the program. */ public static void main(String args[]) { (new Game()).play(); } } /**** CREATURE CLASS ****/ /* (Parent class to Tux, Fox, and KingTux) */ import env3d.EnvObject; import java.util.ArrayList; abstract public class Creature extends EnvObject { private int frame; private double rand; /** * Constructor for objects of class Creature */ public Creature(double x, double y, double z) { setX(x); setY(y); setZ(z); setScale(1); rand = Math.random(); } private void randomGenerator() { rand = Math.random(); } public void move(ArrayList<Creature> creatures, ArrayList<Creature> dead_creatures, ArrayList<Creature> new_creatures) { frame++; if (frame > 12) { randomGenerator(); frame = 0; } // if (rand < 0.25) { // setX(getX()+0.3); // setRotateY(90); // } else if (rand < 0.5) { // setX(getX()-0.3); // setRotateY(270); // } else if (rand < 0.75) { // setZ(getZ()+0.3); // setRotateY(0); // } else if (rand < 1) { // setZ(getZ()-0.3); // setRotateY(180); // } if (rand < 0.5) { setRotateY(getRotateY()-7); } else if (rand < 1) { setRotateY(getRotateY()+7); } setX(getX()+Math.sin(Math.toRadians(getRotateY()))*0.5); setZ(getZ()+Math.cos(Math.toRadians(getRotateY()))*0.5); if (getX() < getScale()) setX(getScale()); if (getX() > 50-getScale()) setX(50 - getScale()); if (getZ() < getScale()) setZ(getScale()); if (getZ() > 50-getScale()) setZ(50 - getScale()); // The move method now handles collision detection if (this instanceof Fox) { for (Creature c : creatures) { if (c.distance(this) < c.getScale()+this.getScale() && c instanceof Tux) { dead_creatures.add(c); } } } } } The rest of the classes are a bit trivial to this specific problem.

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• A Look Inside JSR 360 - CLDC 8

  - by Roger Brinkley

  If you didn't notice during JavaOne the Java Micro Edition took a major step forward in its consolidation with Java Standard Edition when JSR 360 was proposed to the JCP community. Over the last couple of years there has been a focus to move Java ME back in line with it's big brother Java SE. We see evidence of this in JCP itself which just recently merged the ME and SE/EE Executive Committees into a single Java Executive Committee. But just before that occurred JSR 360 was proposed and approved for development on October 29. So let's take a look at what changes are now being proposed. In a way JSR 360 is returning back to the original roots of Java ME when it was first introduced. It was indeed a subset of the JDK 4 language, but as Java progressed many of the language changes were not implemented in the Java ME. Back then the tradeoff was still a functionality, footprint trade off but the major market was feature phones. Today the market has changed and CLDC, while it will still target feature phones, will have it primary emphasis on embedded devices like wireless modules, smart meters, health care monitoring and other M2M devices. The major changes will come in three areas: language feature changes, library changes, and consolidating the Generic Connection Framework.  There have been three Java SE versions that have been implemented since JavaME was first developed so the language feature changes can be divided into changes that came in JDK 5 and those in JDK 7, which mostly consist of the project Coin changes. There were no language changes in JDK 6 but the changes from JDK 5 are: Assertions - Assertions enable you to test your assumptions about your program. For example, if you write a method that calculates the speed of a particle, you might assert that the calculated speed is less than the speed of light. In the example code below if the interval isn't between 0 and and 1,00 the an error of "Invalid value?" would be thrown. private void setInterval(int interval) { assert interval > 0 && interval <= 1000 : "Invalid value?" } Generics - Generics add stability to your code by making more of your bugs detectable at compile time. Code that uses generics has many benefits over non-generic code with: Stronger type checks at compile time. Elimination of casts. Enabling programming to implement generic algorithms. Enhanced for Loop - the enhanced for loop allows you to iterate through a collection without having to create an Iterator or without having to calculate beginning and end conditions for a counter variable. The enhanced for loop is the easiest of the new features to immediately incorporate in your code. In this tip you will see how the enhanced for loop replaces more traditional ways of sequentially accessing elements in a collection. void processList(Vector<string> list) { for (String item : list) { ... Autoboxing/Unboxing - This facility eliminates the drudgery of manual conversion between primitive types, such as int and wrapper types, such as Integer.  Hashtable<Integer, string=""> data = new Hashtable<>(); void add(int id, String value) { data.put(id, value); } Enumeration - Prior to JDK 5 enumerations were not typesafe, had no namespace, were brittle because they were compile time constants, and provided no informative print values. JDK 5 added support for enumerated types as a full-fledged class (dubbed an enum type). In addition to solving all the problems mentioned above, it allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. enum Season {WINTER, SPRING, SUMMER, FALL}; } private Season season; void setSeason(Season newSeason) { season = newSeason; } Varargs - Varargs eliminates the need for manually boxing up argument lists into an array when invoking methods that accept variable-length argument lists. The three periods after the final parameter's type indicate that the final argument may be passed as an array or as a sequence of arguments. Varargs can be used only in the final argument position. void warning(String format, String... parameters) { .. for(String p : parameters) { ...process(p);... } ... } Static Imports -The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members either individually or en masse. Once the static members have been imported, they may be used without qualification. The static import declaration is analogous to the normal import declaration. Where the normal import declaration imports classes from packages, allowing them to be used without package qualification, the static import declaration imports static members from classes, allowing them to be used without class qualification. import static data.Constants.RATIO; ... double r = Math.cos(RATIO * theta); Annotations - Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. There are a number of uses for annotations including information for the compiler, compiler-time and deployment-time processing, and run-time processing. They can be applied to a program's declarations of classes, fields, methods, and other program elements. @Deprecated public void clear(); The language changes from JDK 7 are little more familiar as they are mostly the changes from Project Coin: String in switch - Hey it only took us 18 years but the String class can be used in the expression of a switch statement. Fortunately for us it won't take that long for JavaME to adopt it. switch (arg) { case "-data": ... case "-out": ... Binary integral literals and underscores in numeric literals - Largely for readability, the integral types (byte, short, int, and long) can also be expressed using the binary number system. and any number of underscore characters (_) can appear anywhere between digits in a numerical literal. byte flags = 0b01001111; long mask = 0xfff0_ff08_4fff_0fffl; Multi-catch and more precise rethrow - A single catch block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in the throws clause of a method declaration. catch (IOException | InterruptedException ex) { logger.log(ex); throw ex; } Type Inference for Generic Instance Creation - Otherwise known as the diamond operator, the type arguments required to invoke the constructor of a generic class can be replaced with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context.  map = new Hashtable<>(); Try-with-resource statement - The try-with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try-with-resources statement ensures that each resource is closed at the end of the statement.  try (DataInputStream is = new DataInputStream(...)) { return is.readDouble(); } Simplified varargs method invocation - The Java compiler generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduced a compiler option -Xlint:varargs and the annotations @SafeVarargs and @SuppressWarnings({"unchecked", "varargs"}) to supress these warnings. On the library side there are new features that will be added to satisfy the language requirements above and some to improve the currently available set of APIs.  The library changes include: Collections update - New Collection, List, Set and Map, Iterable and Iteratator as well as implementations including Hashtable and Vector. Most of the work is too support generics String - New StringBuilder and CharSequence as well as a Stirng formatter. The javac compiler  now uses the the StringBuilder instead of String Buffer. Since StringBuilder is synchronized there is a performance increase which has necessitated the wahat String constructor works. Comparable interface - The comparable interface works with Collections, making it easier to reuse. Try with resources - Closeable and AutoCloseable Annotations - While support for Annotations is provided it will only be a compile time support. SuppressWarnings, Deprecated, Override NIO - There is a subset of NIO Buffer that have been in use on the of the graphics packages and needs to be pulled in and also support for NIO File IO subset. Platform extensibility via Service Providers (ServiceLoader) - ServiceLoader interface dos late bindings of interface to existing implementations. It helpe to package an interface and behavior of the implementation at a later point in time.Provider classes must have a zero-argument constructor so that they can be instantiated during loading. They are located and instantiated on demand and are identified via a provider-configuration file in the METAINF/services resource directory. This is a mechansim from Java SE. import com.XYZ.ServiceA; ServiceLoader<ServiceA> sl1= new ServiceLoader(ServiceA.class); Resources: META-INF/services/com.XYZ.ServiceA: ServiceAProvider1 ServiceAProvider2 ServiceAProvider3 META-INF/services/ServiceB: ServiceBProvider1 ServiceBProvider2 From JSR - I would rather use this list I think The Generic Connection Framework (GCF) was previously specified in a number of different JSRs including CLDC, MIDP, CDC 1.2, and JSR 197. JSR 360 represents a rare opportunity to consolidated and reintegrate parts that were duplicated in other specifications into a single specification, upgrade the APIs as well provide new functionality. The proposal is to specify a combined GCF specification that can be used with Java ME or Java SE and be backwards compatible with previous implementations. Because of size limitations as well as the complexity of the some features like InvokeDynamic and Unicode 6 will not be included. Additionally, any language or library changes in JDK 8 will be not be included. On the upside, with all the changes being made, backwards compatibility will still be maintained. JSR 360 is a major step forward for Java ME in terms of platform modernization, language alignment, and embedded support. If you're interested in following the progress of this JSR see the JSR's java.net project for details of the email lists, discussions groups.

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• Deployment Workbench no longer available after PXE boot

  - by Patrick

  Our build process revolves around windows Deployment Workbench. Unfortunately this was setup by someone who is no longer with the company, and no-one has ever dared/needed to make any changes. The other day it stopped working. It turns out that one of our build guys started thinking about changing some stuff in it, clicked something and now it no longer works (He is saying now that he right clicked on the 'LAB' entry in 'Deployment points' and hit 'Update', which took some time to run through apparently). The job has fallen on me to resolve and frankly I'm not sure what I'm doing. I was wondering if someone with more experience than me can provide some pointers as to troubleshooting cos I'm feeling quite a lot in the dark here. On the server I have Deployment Workbench up and running (MMC snapin) version 3.0. There is a WDS service that appears to be running ok, as does the tFTPd service. Nothing specific to this in event logs. From the client side; PXE boot works and gets you to the Win PE launch, and it has the correct company logo as the background (proving to me that its loading win PE from the network). WPEINIT runs, and asks for domain credentials, here the team simply put User/Pass/Domain in the boxes and click ok. Normally the build would kick off. Instead they get an error message saying that the \NATBLU01\Distribution$ share isn't available. Checking \NATBLU01\Distribution$ shows that its there and accessible over the network. Security/permissions seem ok, even 'ANONYMOUS LOGON' has read access to that share so I don't see that being a problem. Digging the trace files from C:\MININT\SMSOSD\OSDLOGS\ after an attempt to run the build I can see an error saying much the same - <![LOG[Validating connection to \\NATBLU01\Distribution$]LOG]!><time="16:42:14.000+000" date="03-15-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[FindFile: The file OSDConnectToUNC.exe could not be found in any standard locations.]LOG]!><time="16:42:14.000+000" date="03-15-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[The network location cannot be reached. For information about network troubleshooting, see Windows Help.]LOG]!><time="16:42:24.000+000" date="03-15-2012" component="LiteTouch" context="" type="3" thread="" file="LiteTouch"> <![LOG[ERROR - Unable to map a network drive to \\NATBLU01\Distribution$.]LOG]!><time="16:42:24.000+000" date="03-15-2012" component="LiteTouch" context="" type="3" thread="" file="LiteTouch"> BDD.LOG shows much the same. Full copies of the .LOG files can both files be found here : BDD.LOG LITETOUCH.LOG I can get to a command prompt from the Win PE that boots from PXE, however there isn't any network stuff there. IPCONFIG returns nothing so none of the tests I would usually run resolve anything. I'm at a loss frankly. I did wonder if I could perhaps start a new build process but if the change to the DeploymentWorkbench has knocked it offline I don't think I'm going to be able to create a new deployment. Failing that; we do have a deployment point labeled type 'Media' which appears to be a DVD ISO image of one of the builds, but its dated 2008, is it possible to export the network build to .ISO and build from DVD? We are looking at new hardware to run this from anyway (for the impending Windows 7 roll out) so a temporary work round isn't going to be too much of a problem. All assistance is appreciated! EDIT : OK. Got it working again. Solution was close to Newmanth's idea. The problem was that our PE image didn't appear to be connecting the network. I had an older copy of the PE boot.WIM on a stick that I had been using for other purposes. I booted that and correctly got a network connection. Showed a correct internal IP and could ping out etc etc. However I was still getting the same errors in all the logs and in when wpeinit was running. What I did seperately was to update the PE image that DeploymentWorkbench was pushing out to display a different back ground. I wanted to prove that I was working in the correct place. Turns out that I wasn't. I went and looked at the other deployment stuff we had on this machine, Windows Deployment Services was installed and although all the install images are off line the boot image was online, so I uploaded the copy from my stick to that. Booted straight off. And fixed. Working. Yay! For anyone stumbling across this in the future you may find that although your deployment images are located in the DeploymentWorkbench, the Win PE boot image you are launching from is located in the associated Windows Deployment Services images.

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• Particle and Physics problem.

  - by Quincy

  This was originally a forum post so I hope you guys don't mind it being 2 questions in one. I am making a game and I got some basic physics implemented. I have 2 problems, 1 with particles being drawn in the wrong place and one with going through walls while jumping in corners. Skip over to about 15 sec video showing the 2 problems : http://youtube.com/watch?v=Tm9nfWsWfiM So the problem with the particles seems to be coming from the removal, as soon as I remove that piece of code it instantly works, but there shouldn't be a problem since they shouldn't even draw when their energy gets to 0 (and then they get removed) So my first question is, how are these particles getting warped all over the screen ? Relevant code : Particle class : class Particle { //Physics public Vector2 position = new Vector2(0,0); public float direction = 180; public float speed = 100; public float energy = 1; protected float startEnergy = 1; //Visual public Sprite sprite; public float rotation = 0; public float scale = 1; public byte alpha = 255; public BlendMode blendMode { get { return sprite.BlendMode; } set { sprite.BlendMode = value; } } public Particle() { } public virtual void Think(float frameTime) { if (energy - frameTime < 0) energy = 0; else energy -= frameTime; position += new Vector2((float)Math.Cos(MathHelper.DegToRad(direction)), (float)Math.Sin(MathHelper.DegToRad(direction))) * speed * frameTime; alpha = (byte)(255 * energy / startEnergy); sprite.Rotation = rotation; sprite.Position = position; sprite.Color = new Color(sprite.Color.R, sprite.Color.G, sprite.Color.B, alpha); } public virtual void Draw(float frameTime) { if (energy > 0) { World.camera.DrawSprite(sprite); } } // Basic particle implementation class BasicSprite : Particle { public BasicSprite(Sprite _sprite) { sprite = _sprite; } } Emitter : class Emitter { protected static Random rand = new Random(); protected List<Particle> particles = new List<Particle>(); public BaseEntity target = null; public Vector2 position = new Vector2(0, 0); public bool Active = true; public float timeAlive = 0; public int particleCount = 0; public int ParticlesPerSeccond { get { return (int)(1 / particleSpawnTime); } set { particleSpawnTime = 1 / (float)value; } } public float dieTime = float.MaxValue; float particleSpawnTime = 0.05f; float spawnTime = 0; public Emitter() { } public virtual void Think(float frametime) { spawnTime += frametime; if (dieTime != float.MaxValue) { timeAlive += frametime; if (timeAlive >= dieTime) Active = false; } if (Active) { if (target != null) position = target.Position; while (spawnTime > particleSpawnTime) { spawnTime -= particleSpawnTime; AddParticle(); particleCount++; } } for (int i = 0; i < particles.Count; i++) { particles[i].Think(frametime); if (particles[i].energy <= 0) { particles.Remove(particles[i]); // As soon as this is removed, it works particleCount--; } } } public virtual void AddParticle() { } public virtual void Draw(float frametime) { foreach (Particle particle in particles) { particle.Draw(frametime); } } } class BloodEmitter : Emitter { Image image; public BloodEmitter() { image = new Image(@"Content/Particles/TinyCircle.png"); image.CreateMaskFromColor(new Color(255, 0, 255, 255)); this.dieTime = 0.5f; this.ParticlesPerSeccond = 100; } public override void AddParticle() { Sprite sprite = new Sprite(image); sprite.Color = new Color((byte)(rand.NextDouble() * 255), (byte)(rand.NextDouble() * 255), (byte)(rand.NextDouble() * 255)); BasicSprite particle = new BasicSprite(sprite); particle.direction = (float)rand.NextDouble() * 360; particle.position = position; particle.blendMode = BlendMode.Alpha; particles.Add(particle); } } The seccond problem is the physics problem, for some reason I can get through the right bottom corner while jumping. I think this is coming from me switching animations but I thought I made it compensate for that. Relevant code : PhysicsEntity : class PhysicsEntity : BaseEntity { // Horizontal movement constants protected const float maxHorizontalSpeed = 1000; protected const float horizontalAcceleration = 15; protected const float horizontalDragAir = 0.95f; protected const float horizontalDragGround = 0.95f; // Vertical movement constants protected const float maxVerticalSpeed = 1000; protected const float verticalAcceleration = 20; // Everything needed for movement and correct animations protected float movement = 0; protected bool onGround = false; protected Vector2 Velocity = new Vector2(0, 0); protected float maxSpeed = 0; float lastThink = 0; float thinkTime = 1f/60f; public PhysicsEntity(Vector2 position, Sprite sprite) : base(position, sprite) { } public override void Draw(float frameTime) { base.Draw(frameTime); } public override void Think(float frameTime) { CalculateMovement(frameTime); base.Think(frameTime); } protected void CalculateMovement(float frameTime) { lastThink += frameTime; while (lastThink > thinkTime) { onGround = false; Velocity.X = MathHelper.Clamp(Velocity.X + horizontalAcceleration * movement, -maxHorizontalSpeed, maxHorizontalSpeed); if (onGround) Velocity.X *= horizontalDragGround; else Velocity.X *= horizontalDragAir; if (maxSpeed < Velocity.X) maxSpeed = Velocity.X; Velocity.Y = MathHelper.Clamp(Velocity.Y + verticalAcceleration, -maxVerticalSpeed, maxVerticalSpeed); lastThink -= thinkTime; DoCollisions(thinkTime); DoAnimations(thinkTime); } } public virtual void DoAnimations(float frameTime) { } public void DoCollisions(float frameTime) { Position.Y += Velocity.Y * frameTime; Vector2 tileCollision = GetTileCollision(); if (tileCollision.X != -1 || tileCollision.Y != -1) { Vector2 collisionDepth = CollisionRectangle.DepthIntersection( new Rectangle( tileCollision.X * World.tileEngine.TileWidth, tileCollision.Y * World.tileEngine.TileHeight, World.tileEngine.TileWidth, World.tileEngine.TileHeight ) ); Position.Y += collisionDepth.Y; if (collisionDepth.Y < 0) onGround = true; Velocity.Y = 0; } Position.X += Velocity.X * frameTime; tileCollision = GetTileCollision(); if (tileCollision.X != -1 || tileCollision.Y != -1) { Vector2 collisionDepth = CollisionRectangle.DepthIntersection( new Rectangle( tileCollision.X * World.tileEngine.TileWidth, tileCollision.Y * World.tileEngine.TileHeight, World.tileEngine.TileWidth, World.tileEngine.TileHeight ) ); Position.X += collisionDepth.X; Velocity.X = 0; } } public void DoCollisions(Vector2 difference) { CollisionRectangle.Y = Position.Y - difference.Y; CollisionRectangle.Height += difference.Y; Vector2 tileCollision = GetTileCollision(); if (tileCollision.X != -1 || tileCollision.Y != -1) { Vector2 collisionDepth = CollisionRectangle.DepthIntersection( new Rectangle( tileCollision.X * World.tileEngine.TileWidth, tileCollision.Y * World.tileEngine.TileHeight, World.tileEngine.TileWidth, World.tileEngine.TileHeight ) ); Position.Y += collisionDepth.Y; if (collisionDepth.Y < 0) onGround = true; Velocity.Y = 0; } CollisionRectangle.X = Position.X - difference.X; CollisionRectangle.Width += difference.X; tileCollision = GetTileCollision(); if (tileCollision.X != -1 || tileCollision.Y != -1) { Vector2 collisionDepth = CollisionRectangle.DepthIntersection( new Rectangle( tileCollision.X * World.tileEngine.TileWidth, tileCollision.Y * World.tileEngine.TileHeight, World.tileEngine.TileWidth, World.tileEngine.TileHeight ) ); Position.X += collisionDepth.X; Velocity.X = 0; } } Vector2 GetTileCollision() { int topLeftTileX = (int)(CollisionRectangle.TopLeft.X / World.tileEngine.TileWidth); int topLeftTileY = (int)(CollisionRectangle.TopLeft.Y / World.tileEngine.TileHeight); int BottomRightTileX = (int)(CollisionRectangle.DownRight.X / World.tileEngine.TileWidth); int BottomRightTileY = (int)(CollisionRectangle.DownRight.Y / World.tileEngine.TileHeight); if (CollisionRectangle.DownRight.Y % World.tileEngine.TileHeight == 0) // If your exactly against the tile don't count that as being inside the tile BottomRightTileY -= 1; if (CollisionRectangle.DownRight.X % World.tileEngine.TileWidth == 0) // If your exactly against the tile don't count that as being inside the tile BottomRightTileX -= 1; for (int i = topLeftTileX; i <= BottomRightTileX; i++) { for (int j = topLeftTileY; j <= BottomRightTileY; j++) { if (World.tileEngine.TileIsSolid(i, j)) { return new Vector2(i, j); } } } return new Vector2(-1, -1); } } Player : enum State { Standing, Running, Jumping, Falling, Sliding, WallSlide } class Player : PhysicsEntity { private State state { get { return currentState; } set { if (currentState != value) { currentState = value; animationChanged = true; } } } private State currentState = State.Standing; private BasicEmitter basicEmitter = new BasicEmitter(); public bool flipped; public bool animationChanged = false; protected const float jumpPower = 600; AnimationManager animationManager; Rectangle DrawRectangle; public override Rectangle CollisionRectangle { get { return new Rectangle( Position.X - DrawRectangle.Width / 2f, Position.Y - DrawRectangle.Height / 2f, DrawRectangle.Width, DrawRectangle.Height ); } } public Player(Vector2 position, Sprite sprite) : base(position, sprite) { // Only posted the relevant bit DrawRectangle = animationManager.currentAnimation.drawingRectangle; } public override void Draw(float frameTime) { World.camera.DrawSprite( Sprite, Position + new Vector2(DrawRectangle.X, DrawRectangle.Y), animationManager.currentAnimation.drawingRectangle ); } public override void Think(float frameTime) { //I only posted the relevant stuff if (animationChanged) { // if the animation has changed make sure we compensate for the change in with and height animationChanged = false; DoCollisions(animationManager.getSizeDifference()); } DoCustomMovement(); base.Think(frameTime); if (!onGround && Velocity.Y > 0) { state = State.Falling; } } void DoCustomMovement() { if (onGround) { if (World.renderWindow.Input.IsKeyDown(KeyCode.W)) { Velocity.Y = -jumpPower; state = State.Jumping; } } } public override void DoAnimations(float frameTime) { string stateName = Enum.GetName(typeof(State), state); if (!animationManager.currentAnimationIs(stateName)) { animationManager.PlayAnimation(stateName); } animationManager.Think(frameTime); DrawRectangle = animationManager.currentAnimation.drawingRectangle; Sprite.Center = new Vector2( DrawRectangle.X + DrawRectangle.Width / 2, DrawRectangle.Y + DrawRectangle.Height / 2 ); Sprite.FlipX(flipped); } So why am I warping through walls ? I have given this some thought but I just can't seem to find out why this is happening. Full source if needed : source : http://www.mediafire.com/?rc7ddo09gnr68zd (download link)

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• How to make a player stay within bounds of world with 2D Camera

  - by Craig

  Im creating a simple top down survival game. At the moment, i have the sprite which is a ship and moves by rotating left or right then going forward in that direction. I have implemented a 2D camera, its always centered on the player. However, when i move towards the bounds of the world that the sprite is in it just keeps on going :( How to i sort it that it stops at the edge of the world and cant go beyond it? Cheers :) Below is the main game class using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace GamesCoursework_1 { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; // player variables Texture2D Ship; Vector2 Ship_Position; float Ship_Rotation = 0.0f; Vector2 Ship_Origin; Vector2 Ship_Velocity; const float tangentialVelocity = 4f; float friction = 0.05f; static Point CameraViewport = new Point(800, 800); Camera2d cam = new Camera2d((int)CameraViewport.X, (int)CameraViewport.Y); //Size of world static Point worldSize = new Point(1600, 1600); // Screen variables static Point worldCenter = new Point(worldSize.X / 2, worldSize.Y / 2); Rectangle playerBounds = new Rectangle(CameraViewport.X / 2, CameraViewport.Y / 2, worldSize.X - CameraViewport.X, worldSize.Y - CameraViewport.Y); Rectangle worldBounds = new Rectangle(0, 0, worldSize.X, worldSize.Y); Texture2D background; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = CameraViewport.X; graphics.PreferredBackBufferHeight = CameraViewport.Y; Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); // TODO: use this.Content to load your game content here Ship = Content.Load<Texture2D>("Ship"); Ship_Origin.X = Ship.Width / 2; Ship_Origin.Y = Ship.Height / 2; background = Content.Load<Texture2D>("aus"); Ship_Position = new Vector2(worldCenter.X, worldCenter.Y); cam.Pos = Ship_Position; cam.Zoom = 1f; } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { // TODO: Unload any non ContentManager content here } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // TODO: Add your update logic here Ship_Position = Ship_Velocity + Ship_Position; keyPressed(); base.Update(gameTime); } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // TODO: Add your drawing code here spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend, null, null, null,null, cam.get_transformation(GraphicsDevice)); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.Draw(Ship, Ship_Position, Ship.Bounds, Color.White, Ship_Rotation, Ship_Origin, 1.0f, SpriteEffects.None, 0f); spriteBatch.End(); base.Draw(gameTime); } private void Ship_Move(Vector2 move) { Ship_Position += move; } private void keyPressed() { KeyboardState keyState; // Move right keyState = Keyboard.GetState(); if (keyState.IsKeyDown(Keys.Right)) { Ship_Rotation = Ship_Rotation + 0.1f; } if (keyState.IsKeyDown(Keys.Left)) { Ship_Rotation = Ship_Rotation - 0.1f; } if (keyState.IsKeyDown(Keys.Up)) { Ship_Velocity.X = (float)Math.Cos(Ship_Rotation) * tangentialVelocity; Ship_Velocity.Y = (float)Math.Sin(Ship_Rotation) * tangentialVelocity; if ((int)Ship_Position.Y < playerBounds.Bottom && (int)Ship_Position.Y > playerBounds.Top) cam._pos.Y = Ship_Position.Y; if ((int)Ship_Position.X > playerBounds.Left && (int)Ship_Position.X < playerBounds.Right) cam._pos.X = Ship_Position.X; //tried world bounds here if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, -tangentialVelocity * 2); if (!worldBounds.Contains(new Point((int)Ship_Position.X, (int)Ship_Position.Y))) Ship_Position -= new Vector2(0.0f, 2 * tangentialVelocity); } else if(Ship_Velocity != Vector2.Zero) { float i = Ship_Velocity.X; float j = Ship_Velocity.Y; Ship_Velocity.X = i -= friction * i; Ship_Velocity.Y = j -= friction * j; if ((int)Ship_Position.Y < playerBounds.Bottom && (int)Ship_Position.Y > playerBounds.Top) cam._pos.Y = Ship_Position.Y; if ((int)Ship_Position.X > playerBounds.Left && (int)Ship_Position.X < playerBounds.Right) cam._pos.X = Ship_Position.X; } if (keyState.IsKeyDown(Keys.Q)) { if (cam.Zoom < 2f) cam.Zoom += 0.05f; } if (keyState.IsKeyDown(Keys.A)) { if (cam.Zoom > 0.3f) cam.Zoom -= 0.05f; } } } } my 2d camera class using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; namespace GamesCoursework_1 { public class Camera2d { protected float _zoom; // Camera Zoom public Matrix _transform; // Matrix Transform public Vector2 _pos; // Camera Position protected float _rotation; // Camera Rotation public int _viewportWidth, _viewportHeight; // viewport size public Camera2d(int ViewportWidth, int ViewportHeight) { _zoom = 1.0f; _rotation = 0.0f; _pos = Vector2.Zero; _viewportWidth = ViewportWidth; _viewportHeight = ViewportHeight; } // Sets and gets zoom public float Zoom { get { return _zoom; } set { _zoom = value; if (_zoom < 0.1f) _zoom = 0.1f; } // Negative zoom will flip image } public float Rotation { get { return _rotation; } set { _rotation = value; } } // Auxiliary function to move the camera public void Move(Vector2 amount) { _pos += amount; } // Get set position public Vector2 Pos { get { return _pos; } set { _pos = value; } } public Matrix get_transformation(GraphicsDevice graphicsDevice) { _transform = // Thanks to o KB o for this solution Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) * Matrix.CreateRotationZ(Rotation) * Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) * Matrix.CreateTranslation(new Vector3(_viewportWidth * 0.5f, _viewportHeight * 0.5f, 0)); return _transform; } } }

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• 1136: Incorrect number of arguments. Expected 0.? AS3 Flash Cs4

  - by charmaine

  Basically i am working through a book called..Foundation Actionscript 3.0 Animation, making things move. i am now on Chapter 9 - collision detection. On two lines of my code i get the 1135 error, letting me know that i have an incorrect number of arguments. Can anybody help me out on why this may be? package { import flash.display.Sprite; import flash.events.Event; public class Bubbles extends Sprite { private var balls:Array; private var numBalls:Number = 10; private var centerBall:Ball; private var bounce:Number = -1; private var spring:Number = 0.2; public function Bubbles() { init(); } private function init():void { balls = new Array(); centerBall = new Ball(100, 0xcccccc); addChild(centerBall); centerBall.x = stage.stageWidth / 2; centerBall.y = stage.stageHeight / 2; for(var i:uint = 0; i < numBalls; i++) { var ball:Ball = new Ball(Math.random() * 40 + 5, Math.random() * 0xffffff); ball.x = Math.random() * stage.stageWidth; ball.y = Math.random() * stage.stageHeight; ball.vx = Math.random() * 6 - 3; ball.vy = Math.random() * 6 - 3; addChild(ball); balls.push(ball); } addEventListener(Event.ENTER_FRAME, onEnterFrame); } private function onEnterFrame(event:Event):void { for(var i:uint = 0; i < numBalls; i++) { var ball:Ball = balls[i]; move(ball); var dx:Number = ball.x - centerBall.x; var dy:Number = ball.y - centerBall.y; var dist:Number = Math.sqrt(dx * dx + dy * dy); var minDist:Number = ball.radius + centerBall.radius; if(dist < minDist) { var angle:Number = Math.atan2(dy, dx); var tx:Number = centerBall.x + Math.cos(angle) * minDist; var ty:Number = centerBall.y + Math.sin(angle) * minDist; ball.vx += (tx - ball.x) * spring; ball.vy += (ty - ball.y) * spring; } } } ***private function move(ball:Ball):void*** { ball.x += ball.vx; ball.y += ball.vy; if(ball.x + ball.radius > stage.stageWidth) { ball.x = stage.stageWidth - ball.radius; ball.vx *= bounce; } else if(ball.x - ball.radius < 0) { ball.x = ball.radius; ball.vx *= bounce; } ***if(ball.y + ball.radius > stage.stageHeight)*** { ball.y = stage.stageHeight - ball.radius; ball.vy *= bounce; } else if(ball.y - ball.radius < 0) { ball.y = ball.radius; ball.vy *= bounce; } } } } The bold parts are the lines im having trouble with! please help..thanks in advance!!

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• Multiple viewport problem

  - by PSilo

  I'm setting up so I can switch between either one or four viewports but I got some trouble. In my bottom right viewport I got camera view, the same camera that I can switch to full view on. The other three viewports are working with fixed locations but the bottom right viewport is compressed on the y scale and half of the picture on the x scale is missing. void display(int what) { if(what==5){glViewport(0, 0, w, h); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); ca.lookAt();} if(what==1){glViewport(0, 0, w/2, h/2); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt(75,15,-5,0,5,-5,0,1,0);} if(what==2){glViewport(w/2, h/2, w, h); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt(0,110,0,20,0,20,1,0,0);} if(what==3){glViewport(w/2, 0, w, h/2); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0f, float(320) / float(240), 0.1f, 100.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); ca.lookAt();} if(what==4){glViewport(0, h/2, w/2, h); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt(185,75,25,0,28,0,0,1,0);} //glMatrixMode(GL_MODELVIEW); //glLoadIdentity(); ////gluLookAt(cos(shared.time) * shared.distance, 10, sin(shared.time) * shared.distance, 0, 0, 0, 0, 1, 0); // Roterar kameran kring origo genom att skapa en ny vymatris varje bildruta ////ca.orbitYaw(0.05); //ca.lookAt(); glClearColor(0, 0, 0, 1); glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); drawScene(); drawCamera(); glutSwapBuffers(); } void viewport(){ glEnable(GL_SCISSOR_TEST); if(!divided_view_port) { glViewport(0, 0, w, h); glScissor(0,0,640,480); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0f, w / h, 0.1f, 100.0f); display(5); } else { ////////////////////// bottom left - working glViewport(0, 0, w/2, h/2); glScissor(0,0,w/2,h/2); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0f, w / h, 0.1f, 300.0f); display(1); ////////////////////// ////////////////////// top right - working glViewport(w/2, h/2, w, h); glScissor(w/2,h/2,w,h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0f, w / h, 0.1f, 300.0f); display(2); ////////////////////// ////////////////////// bottom right -working glViewport(w/2, 0, w, h/2); glScissor(w/2,0,w,h/2); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0f, w / h, 0.1f, 300.0f); display(3); //////////////////////// ////////////////////////// top left glViewport(0, h/2, w/2, h); glScissor(0,h/2,w/2,h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0f, w / h, 0.1f, 300.0f); display(4); /////////////////////////// } glDisable(GL_SCISSOR_TEST); glMatrixMode(GL_MODELVIEW); }

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• Cakephp - Banner Problem

  - by Joe Elliott

  Hi guys I have a banner rotator on my main page and it was working but it has stopped. All I have done before it stopped was modified some of the db fields. I added to fields position and company and deleted the field 'description.' It was a friend of a friend that made this part of the site for me while i was on holiday so i dont know which files i should show you cos dont know exactly what hes done but im guessing the following ones are the ones you need. banner_view <div id="banner"> <?php if(!empty($banners) && ($banners['Banner']['position']=='Top')){ foreach($banners as $banner){ ?> <a href="<?php echo $banner['Banner']['url']; ?>"><img src="<?php echo $banner['Banner']['path']; ?>" alt="<?php echo $banner['Banner']['company']; ?>" /></a> <?php } } ?> </div> banner_controller <?php class BannersController extends AppController { var $name = 'Banners'; var $helpers = array('Html', 'Form', 'Ajax','Javascript'); var $layout = 'ajax'; var $components = array('Session', 'Cookie'); function beforeFilter() { parent::beforeFilter(); $this->Auth->allow('index','featrot'); if(strpos($this->here, 'admin')) { $this->layout = 'admin'; } } function index() { Configure::write('debug',0); $this->Banner->recursive = 0; $this->paginate['Banner']; $banners = $this->paginate(); if($banners) { $this->set('banners', $banners); } } function featrot() { Configure::write('debug',0); $this->Banner->recursive = 0; $this->paginate['Banner']; $banners = $this->paginate(); if($banners) { $this->set('banners', $banners); } } function admin_edit(){ $this->pageTitle='Admin section - .: Banners Edit:.'; $banners = $this->Banner->find('first'); $id = $banners['Banner']['id']; if (!empty($this->data)) { $this->Banner->id = $id; if ($this->Banner->save($this->data)) { $this->Session->setFlash(__('The Banner has been updated', true)); } else { $this->Session->setFlash(__('The Banner could not update. Please, try again.', true)); } } if (empty($this->data)) { $this->data = $this->Banner->read(null, $id); } } function admin_display_banners($id=null){ $this->pageTitle='Admin section - .: Banners Setting :.'; if (!empty($this->data)) { $this->Banner->id = $id; if ($this->Banner->save($this->data)) { $this->Session->setFlash(__("Banner#$id has been updated", true)); $this->Banner->id = null; } else { $this->Session->setFlash(__("Banner#$id could not update. Please, try again.", true)); } } $this->data = null; $this->Banner->recursive = -1; $this->paginate['Banner']; $banners = $this->paginate('Banner'); $this->set('banners', $banners); } } ?> banner_model <?php class Banner extends AppModel { var $name = 'Banner'; } ?> Hope this is all the details you need. Thanks in advance folks :) Joe :)

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• Calculate new position of player

  - by user1439111

  Edit: I will summerize my question since it is very long (Thanks Len for pointing it out) What I'm trying to find out is to get a new position of a player after an X amount of time. The following variables are known: - Speed - Length between the 2 points - Source position (X, Y) - Destination position (X, Y) How can I calculate a position between the source and destion with these variables given? For example: source: 0, 0 destination: 10, 0 speed: 1 so after 1 second the players position would be 1, 0 The code below works but it's quite long so I'm looking for something shorter/more logical ====================================================================== I'm having a hard time figuring out how to calculate a new position of a player ingame. This code is server sided used to track a player(It's a emulator so I don't have access to the clients code). The collision detection of the server works fine I'm using bresenham's line algorithm and a raycast to determine at which point a collision happens. Once I deteremined the collision I calculate the length of the path the player is about to walk and also the total time. I would like to know the new position of a player each second. This is the code I'm currently using. It's in C++ but I am porting the server to C# and I haven't written the code in C# yet. // Difference between the source X - destination X //and source y - destionation Y float xDiff, yDiff; xDiff = xDes - xSrc; yDiff = yDes - ySrc; float walkingLength = 0.00F; float NewX = xDiff * xDiff; float NewY = yDiff * yDiff; walkingLength = NewX + NewY; walkingLength = sqrt(walkingLength); const float PI = 3.14159265F; float Angle = 0.00F; if(xDes >= xSrc && yDes >= ySrc) { Angle = atanf((yDiff / xDiff)); Angle = Angle * 180 / PI; } else if(xDes < xSrc && yDes >= ySrc) { Angle = atanf((-xDiff / yDiff)); Angle = Angle * 180 / PI; Angle += 90.00F; } else if(xDes < xSrc && yDes < ySrc) { Angle = atanf((yDiff / xDiff)); Angle = Angle * 180 / PI; Angle += 180.00F; } else if(xDes >= xSrc && yDes < ySrc) { Angle = atanf((xDiff / -yDiff)); Angle = Angle * 180 / PI; Angle += 270.00F; } float WalkingTime = (float)walkingLength / (float)speed; bool Done = false; float i = 0; while(i < walkingLength) { if(Done == true) { break; } if(WalkingTime >= 1000) { Sleep(1000); i += speed; WalkTime -= 1000; } else { Sleep(WalkTime); i += speed * WalkTime; WalkTime -= 1000; Done = true; } if(Angle >= 0 && Angle < 90) { float xNew = cosf(Angle * PI / 180) * i; float yNew = sinf(Angle * PI / 180) * i; float NewCharacterX = xSrc + xNew; float NewCharacterY = ySrc + yNew; } I have cut the last part of the loop since it's just 3 other else if statements with 3 other angle conditions and the only change is the sin and cos. The given speed parameter is the speed/second. The code above works but as you can see it's quite long so I'm looking for a new way to calculate this. btw, don't mind the while loop to calculate each new position I'm going to use a timer in C# Thank you very much

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• Why does my Opengl es android testbed app not render anything besides a red screen?

  - by nathan

  For some reason my code here (this is the entire thing) doesnt actually render anything besides a red screen.. can anyone tell me why? package com.ntu.way2fungames.earth.testbed; import java.nio.FloatBuffer; import javax.microedition.khronos.egl.EGLConfig; import javax.microedition.khronos.opengles.GL10; import android.app.Activity; import android.content.Context; import android.opengl.GLSurfaceView; import android.opengl.GLSurfaceView.Renderer; import android.os.Bundle; public class projectiles extends Activity { GLSurfaceView lGLView; Renderer lGLRenderer; float projectilesX[]= new float[5001]; float projectilesY[]= new float[5001]; float projectilesXa[]= new float[5001]; float projectilesYa[]= new float[5001]; float projectilesTheta[]= new float[5001]; float projectilesSpeed[]= new float[5001]; private static FloatBuffer drawBuffer; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); SetupProjectiles(); Context mContext = this.getWindow().getContext(); lGLView= new MyView(mContext); lGLRenderer= new MyRenderer(); lGLView.setRenderer(lGLRenderer); setContentView(lGLView); } private void SetupProjectiles() { int i=0; for (i=5000;i>0;i=i-1){ projectilesX[i] = 240; projectilesY[i] = 427; float theta = (float) ((i/5000)*Math.PI*2); projectilesXa[i] = (float) Math.cos(theta); projectilesYa[i] = (float) Math.sin(theta); projectilesTheta[i]= theta; projectilesSpeed[i]= (float) (Math.random()+1); } } public class MyView extends GLSurfaceView{ public MyView(Context context) { super(context); // TODO Auto-generated constructor stub } } public class MyRenderer implements Renderer{ private float[] projectilecords = new float[] { .0f, .5f, 0, -.5f, 0f, 0, .5f, 0f, 0, 0, -5f, 0, }; @Override public void onDrawFrame(GL10 gl) { gl.glClear(GL10.GL_COLOR_BUFFER_BIT); gl.glMatrixMode(GL10.GL_MODELVIEW); //gl.glLoadIdentity(); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); for (int i=5000;i>4500;i=i-1){ //drawing section gl.glLoadIdentity(); gl.glColor4f(.9f, .9f,.9f,.9f); gl.glTranslatef(projectilesY[i], projectilesX[i],1); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, drawBuffer); gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 12); //physics section projectilesX[i]=projectilesX[i]+projectilesXa[i]; projectilesY[i]=projectilesY[i]+projectilesYa[i]; } gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); } @Override public void onSurfaceChanged(GL10 gl, int width, int height) { if (height == 0) height = 1; // draw on the entire screen gl.glViewport(0, 0, width, height); // setup projection matrix gl.glMatrixMode(GL10.GL_PROJECTION); gl.glLoadIdentity(); gl.glOrthof(0,width,height,0, -100, 100); } @Override public void onSurfaceCreated(GL10 gl, EGLConfig arg1) { gl.glShadeModel(GL10.GL_SMOOTH); gl.glClearColor(1f, .01f, .01f, 1f); gl.glClearDepthf(1.0f); gl.glEnable(GL10.GL_DEPTH_TEST); gl.glDepthFunc(GL10.GL_LEQUAL); gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); drawBuffer = FloatBuffer.wrap(projectilecords); } } }

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• Recursing data into a 2 dimensional array in PHP 5

  - by user315699

  I'm getting bamboozled by "for each" loops and two dimensional arrays, and I'm a php newb so please bear with me (and ignore any variables with the word "image" - it's all about the mp3s, I just didn't change it from the xml tutorial) I found a php function on the net that list files in a directory, the output of which is: Array ( [0] = audio/1.mp3 [1] = audio/2.mp3 [2] = audio/3.mp3 [3] = audio/4.mp3 [4] = audio/5.mp3 ) As expected. And another that lists some info about mp3 files. $mp3datafile = 'audio/1.mp3'; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); print_r($mp3dataArray); unset($mp3dataArray); The output of which is Array ( [Filesize] = 31972 [Encoding] = CBR [etc] ) In order to automatically build RSS for a podcast, I need to generate XML for each item. So far so good. This is how I'm making the xml foreach ($imagearray as $key = $val) { $tnsoundfile = $xml_generator-addChild('item'); $tnsoundfile-addChild('title', $podcasttitle); $enclosure = $tnsoundfile-addChild('enclosure'); $enclosure-addAttribute('url', $val); // that's the filename $enclosure-addAttribute('length', $mp3dataArray[Filesize]); // << Length is file length, not time. But later I also need $mp3dataArray[Length mm:ss] for duration tag. $enclosure-addAttribute('type', 'audio/mpeg'); $tnsoundfile-addChild('guid', $path_to_image_dir.'/'.$val); } (The above has been truncated, I realise it's not proper xml right now, but it was just to show what was going on). Perfect. But I need to do it for as many files as there are in the directory. So, I have an array of the names of the files in the directory in $mp3data And, I have an array of mp3 data in $mp3dataArray from one iteration of the get_metadata() function. If I do the following, then I get a nice list of the mp3 data of the 5 files in the directory: foreach ($mp3data as $key = $val) { $mp3datafile = $val; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); print_r($mp3dataArray); unset($mp3dataArray); } As expected. Where I'm struggling, and have been for most of the day in spite of reading many forums and tutorials, is how to populate the "second dimension" of the array, so that it goes through 1,2,3,4 and 5.mp3 (or however many there are), extracts the metadata, then allows me to use it in the xml section above. Here's what I have foreach ($mp3data as $key = $val) { $mp3datafile = $val; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); $mp3testarray = array($mp3dataArray); } print_r($mp3dataArray); Shouldn't that line print_r($mp3dataArray); give me a nice list of 5 lots of mp3 data, in the way it did when I recursed through the loop as before? Cos this is driving me nuts! It must be something so simple, and any help would be greatly appreciated. Thank you in advance.

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• OpenGL alpha blending issue with back face visible.

  - by Max

  I'm trying to display "transparent" surfaces (not closed volumes) with both the front face and back face are visible (not culled). For example displaying a cone or cylinder where the transparency is applied on both sides. There are some visible artifacts where some part of the surface does not seems to be handling the alpha values correctly. The issue it seems is when I (opengl) is trying to apply the alpha from the front side of the surface to the backside of the surface. (when both the inside/outside of the surface is visible). void init() { glMatrixMode(GL_PROJECTION); gluPerspective( /* field of view in degree */ 40.0, /* aspect ratio */ 1.0, /* Z near */ 1.0, /* Z far */ 10.0); glMatrixMode(GL_MODELVIEW); gluLookAt(0.0, 0.0, 5.0, /* eye is at (0,0,5) */ 0.0, 0.0, 0.0, /* center is at (0,0,0) */ 0.0, 1.0, 0.); /* up is in positive Y direction */ glTranslatef(0.0, 0.6, -1.0); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glLightfv(GL_LIGHT0, GL_AMBIENT, light0_ambient); glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_diffuse); glLightfv(GL_LIGHT1, GL_DIFFUSE, light1_diffuse); glLightfv(GL_LIGHT1, GL_POSITION, light1_position); glLightfv(GL_LIGHT2, GL_DIFFUSE, light2_diffuse); glLightfv(GL_LIGHT2, GL_POSITION, light2_position); glClearDepth(1.0f); glEnable(GL_DEPTH_TEST); //glEnable(GL_CULL_FACE); glFrontFace( GL_CW ); glShadeModel(GL_SMOOTH); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); } void draw () { static GLfloat amb[] = {0.4f, 0.4f, 0.4f, 0.0f}; static GLfloat dif[] = {1.0f, 1.0f, 1.0f, 0.0f}; static GLfloat back_amb[] = {0.4f, 0.4f, 0.4f, 1.0f}; static GLfloat back_dif[] = {1.0f, 1.0f, 1.0f, 1.0f}; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_LIGHT1); glDisable(GL_LIGHT2); amb[3] = dif[3] = 0.5f;// cos(s) / 2.0f + 0.5f; glMaterialfv(GL_FRONT, GL_AMBIENT, amb); glMaterialfv(GL_FRONT, GL_DIFFUSE, dif); glMaterialfv(GL_BACK, GL_AMBIENT, back_amb); glMaterialfv(GL_BACK, GL_DIFFUSE, back_dif); glPushMatrix(); glTranslatef(-0.3f, -0.3f, 0.0f); glRotatef(angle1, 1.0f, 5.0f, 0.0f); glutSolidCone(1.0, 1.0, 50, 2 ); glPopMatrix(); ///... SwapBuffers(wglGetCurrentDC()); // glutSwapBuffers(); } The code is based on : http://www.sgi.com/products/software/opengl/examples/glut/examples/source/blender.c tinyurled links to 2 images on flickr showing the issue (but from out production code, not the above code, but both have the same kind of problems): http://flic.kr/p/99soxy and http://flic.kr/p/99pg18 Thanks. Max.

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• ActionScript Gradient Banding Problem

  - by TheDarkIn1978

  i'm having a strange issue with banding between certain colors of a gradient. to create the gradient, i'm drawing evenly spaced circle wedges from the center to the border, and filling each circle wedge from a bitmap line gradient pixel in a loop. public class ColorWheel extends Sprite { private static const DEFAULT_RADIUS:Number = 100; private static const DEFAULT_BANDING_QUALITY:int = 3600; public function ColorWheel(nRadius:Number = DEFAULT_RADIUS) { init(nRadius); } public function init(nRadius:Number = DEFAULT_RADIUS):void { var nRadians : Number; var nColor : Number; var objMatrix : Matrix = new Matrix(); var nX : Number; var nY : Number; var previousX : Number = nRadius; var previousY : Number = 0; var leftToRightColors:Array = new Array(0xFF0000, 0xFFFF00, 0x00FF00, 0x00FFFF, 0x0000FF, 0xFF00FF); leftToRightColors.push(leftToRightColors[0]); var leftToRightAlphas:Array = new Array(); var leftToRightRatios:Array = new Array(); var leftToRightPartition:Number = 255 / (leftToRightColors.length - 1); //Push arrays for (var j:int = 0; j < leftToRightColors.length; j++) { leftToRightAlphas.push(1); leftToRightRatios.push(j * leftToRightPartition); } var leftToRightColorsMatrix:Matrix = new Matrix(); leftToRightColorsMatrix.createGradientBox(DEFAULT_BANDING_QUALITY, 1); //Produce a horizontal leftToRightLine sprite var leftToRightLine:Sprite = new Sprite(); leftToRightLine.graphics.lineStyle(1, 0, 1, false, LineScaleMode.NONE, CapsStyle.NONE); leftToRightLine.graphics.lineGradientStyle(GradientType.LINEAR, leftToRightColors, leftToRightAlphas, leftToRightRatios, leftToRightColorsMatrix); leftToRightLine.graphics.moveTo(0, 0); leftToRightLine.graphics.lineTo(DEFAULT_BANDING_QUALITY, 0); //Assign bitmapData to the leftToRightLine var leftToRightLineBitmapData:BitmapData = new BitmapData(leftToRightLine.width, leftToRightLine.height); leftToRightLineBitmapData.draw(leftToRightLine); for(var i:int = 1; i < (DEFAULT_BANDING_QUALITY + 1); i++) { // Convert the degree to radians. nRadians = i * (Math.PI / (DEFAULT_BANDING_QUALITY / 2)); // OR the individual color channels together. nColor = leftToRightLineBitmapData.getPixel(i-1, 0); // Calculate the coordinate in which the line should be drawn to. nX = nRadius * Math.cos(nRadians); nY = nRadius * Math.sin(nRadians); // Create a matrix for the wedges gradient color. objMatrix.createGradientBox(nRadius * 2, nRadius * 2, nRadians, -nRadius, -nRadius); graphics.beginGradientFill(GradientType.LINEAR, [nColor, nColor], [1, 1], [127, 255], objMatrix); graphics.moveTo( 0, 0 ); graphics.lineTo( previousX, previousY ); graphics.lineTo( nX, nY ); graphics.lineTo( 0, 0 ); graphics.endFill(); previousX = nX; previousY = nY; } } } i'm creating a circle with 3600 wedges, although it doesn't look like it based on the screen shot within the orange color that is produced from gradating from red to yellow numbers. adding a orange number between red and yellow doesn't help. but if i create the circle with only 360 wedges, the gradient banding is much more obvious. 3600 is probably overkill, and doesn't really add more detail over, say, making the circle of 1440 wedges, but i don't know any other way to slightly elevate this banding issue. any ideas how i can fix this, or what i'm doing wrong? could it be caused by the circleMatrix rotation?

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• Oval collision detection not working properly

  - by William

  So I'm trying to implement a test where a oval can connect with a circle, but it's not working. edist = (float) Math.sqrt(Math.pow((px + ((pwidth/2) )) - (bx + (bsize/2)), 2) + Math.pow(-((py + ((pwidth/2)) ) - (bx + (bsize/2))), 2)); and here is the full code (requires Slick2D): import org.newdawn.slick.AppGameContainer; import org.newdawn.slick.BasicGame; import org.newdawn.slick.Color; import org.newdawn.slick.GameContainer; import org.newdawn.slick.Graphics; import org.newdawn.slick.Input; import org.newdawn.slick.SlickException; public class ColTest extends BasicGame{ float px = 50; float py = 50; float pheight = 50; float pwidth = 50; float bx = 200; float by = 200; float bsize = 200; float edist; float pspeed = 3; Input input; public ColTest() { super("ColTest"); } @Override public void init(GameContainer gc) throws SlickException { } @Override public void update(GameContainer gc, int delta) throws SlickException { input = gc.getInput(); try{ if(input.isKeyDown(Input.KEY_UP)) py-=pspeed; if(input.isKeyDown(Input.KEY_DOWN)) py+=pspeed; if(input.isKeyDown(Input.KEY_LEFT)) px-=pspeed; if(input.isKeyDown(Input.KEY_RIGHT)) px+=pspeed; } catch(Exception e){} } public void render(GameContainer gc, Graphics g) throws SlickException { g.setColor(new Color(255,255,255)); g.drawString("col: " + col(), 10, 10); g.drawString("edist: " + edist + " dist: " + dist, 10, 100); g.fillRect(px, py, pwidth, pheight); g.setColor(new Color(255,0,255)); g.fillOval(px, py, pwidth, pheight); g.setColor(new Color(255,255,255)); g.fillOval(200, 200, 200, 200); } public boolean col(){ edist = (float) Math.sqrt(Math.pow((px + ((pwidth/2) )) - (bx + (bsize/2)), 2) + Math.pow(-((py + ((pwidth/2)) ) - (bx + (bsize/2))), 2)); if(edist <= (bsize/2) + (px + (pwidth/2))) return true; else return false; } public float rotate(float x, float y, float ox, float oy, float a, boolean b) { float dst = (float) Math.sqrt(Math.pow(x-ox,2.0)+ Math.pow(y-oy,2.0)); float oa = (float) Math.atan2(y-oy,x-ox); if(b) return (float) Math.cos(oa + Math.toRadians(a))*dst+ox; else return (float) Math.sin(oa + Math.toRadians(a))*dst+oy; } public static void main(String[] args) throws SlickException { AppGameContainer app = new AppGameContainer( new ColTest() ); app.setShowFPS(false); app.setAlwaysRender(true); app.setTargetFrameRate(60); app.setDisplayMode(800, 600, false); app.start(); } }

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• Changes to data inside class not being shown when accessed from outside class.

  - by Hypatia

  I have two classes, Car and Person. Car has as one of its members an instance of Person, driver. I want to move a car, while keeping track of its location, and also move the driver inside the car and get its location. However, while this works from inside the class (I have printed out the values as they are calculated), when I try to access the data from main, there's nothing there. I.e. the array position[] ends up empty. I am wondering if there is something wrong with the way I have set up the classes -- could it be a problem of the scope of the object? I have tried simplifying the code so that I only give what is necessary. Hopefully that covers everything that you would need to see. The constructer Car() fills the offset array of driver with nonzero values. class Car{ public: Container(float=0,float=0,float=0); ~Container(); void move(float); void getPosition(float[]); void getDriverPosition(float[]); private: float position[3]; Person driver; float heading; float velocity; }; class Person{ public: Person(float=0,float=0,float=0); ~Person(); void setOffset(float=0,float=0,float=0); void setPosition(float=0,float=0,float=0); void getOffset(float[]); void getPosition(float[]); private: float position[3]; float offset[3]; }; Some of the functions: void Car::move(float time){ float distance = velocity*time; location[0] += distance*cos(PI/2 - heading); location[1] += distance*sin(PI/2 - heading); float driverLocation [3]; float offset[3]; driver->getOffset(offset); for (int i = 0; i < 3; i++){ driverLocation[i] = offset[i] + location[i]; } } void Car::getDriverPosition(float p[]){ driver.getPosition(p); } void Person::getPosition(float p[]){ for (int i = 0; i < 3; i++){ p[i] = position[i]; } } void Person::getOffset(float o[]){ for (int i = 0; i < 3; i++){ o[i] = offset[i]; } } In Main: Car * car = new Car(); car->move(); float p[3]; car->getDriverPosition(p); When I print driverLocation[] inside the move() function, I have actual nonzero values. When I print p[] inside main, all I get are zeros.

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• problems in trying ieee 802.15.4 working from msk

  - by asel

  Hi, i took a msk code from dsplog.com and tried to modify it to test the ieee 802.15.4. There are several links on that site for ieee 802.15.4. Currently I am getting simulated ber results all approximately same for all the cases of Eb_No values. Can you help me to find why? thanks in advance! clear PN = [ 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0; 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0; 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0; 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1; 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1; 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0; 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1; 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1; 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1; 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1; 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1; 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0; 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0; 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1; 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0; 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0; ]; N = 5*10^5; % number of bits or symbols fsHz = 1; % sampling period T = 4; % symbol duration Eb_N0_dB = [0:10]; % multiple Eb/N0 values ct = cos(pi*[-T:N*T-1]/(2*T)); st = sin(pi*[-T:N*T-1]/(2*T)); for ii = 1:length(Eb_N0_dB) tx = []; % MSK Transmitter ipBit = round(rand(1,N/32)*15); for k=1:length(ipBit) sym = ipBit(k); tx = [tx PN((sym+1),1:end)]; end ipMod = 2*tx - 1; % BPSK modulation 0 -> -1, 1 -> 1 ai = kron(ipMod(1:2:end),ones(1,2*T)); % even bits aq = kron(ipMod(2:2:end),ones(1,2*T)); % odd bits ai = [ai zeros(1,T) ]; % padding with zero to make the matrix dimension match aq = [zeros(1,T) aq ]; % adding delay of T for Q-arm % MSK transmit waveform xt = 1/sqrt(T)*[ai.*ct + j*aq.*st]; % Additive White Gaussian Noise nt = 1/sqrt(2)*[randn(1,N*T+T) + j*randn(1,N*T+T)]; % white gaussian noise, 0dB variance % Noise addition yt = xt + 10^(-Eb_N0_dB(ii)/20)*nt; % additive white gaussian noise % MSK receiver % multiplying with cosine and sine waveforms xE = conv(real(yt).*ct,ones(1,2*T)); xO = conv(imag(yt).*st,ones(1,2*T)); bHat = zeros(1,N); bHat(1:2:end) = xE(2*T+1:2*T:end-2*T); % even bits bHat(2:2:end) = xO(3*T+1:2*T:end-T); % odd bits result=zeros(16,1); chiplen=32; seqstart=1; recovered = []; while(seqstart<length(bHat)) A = bHat(seqstart:seqstart+(chiplen-1)); for j=1:16 B = PN(j,1:end); result(j)=sum(A.*B); end [value,index] = max(result); recovered = [recovered (index-1)]; seqstart = seqstart+chiplen; end; %# create binary string - the 4 forces at least 4 bits bstr1 = dec2bin(ipBit,4); bstr2 = dec2bin(recovered,4); %# convert back to numbers (reshape so that zeros are preserved) out1 = str2num(reshape(bstr1',[],1))'; out2 = str2num(reshape(bstr2',[],1))'; % counting the errors nErr(ii) = size(find([out1 - out2]),2); end nErr/(length(ipBit)*4) % simulated ber theoryBer = 0.5*erfc(sqrt(10.^(Eb_N0_dB/10))) % theoretical ber

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• Help understanding some OpenGL stuff

  - by shinjuo

  I am working with some code to create a triangle that moves with arrow keys. I want to create a second object that moves independently. This is where I am having trouble, I have created the second actor, but cannot get it to move. There is too much code to post it all so I will just post a little and see if anyone can help at all. ogl_test.cpp #include "platform.h" #include "srt/scheduler.h" #include "model.h" #include "controller.h" #include "model_module.h" #include "graphics_module.h" class blob : public actor { public: blob(float x, float y) : actor(math::vector2f(x, y)) { } void render() { transform(); glBegin(GL_TRIANGLES); glVertex3f(0.25f, 0.0f, -5.0f); glVertex3f(-.5f, 0.25f, -5.0f); glVertex3f(-.5f, -0.25f, -5.0f); glEnd(); end_transform(); } void update(controller& c, float dt) { if (c.left_key) { rho += pi / 9.0f * dt; c.left_key = false; } if (c.right_key) { rho -= pi / 9.0f * dt; c.right_key = false; } if (c.up_key) { v += .1f * dt; c.up_key = false; } if (c.down_key) { v -= .1f * dt; if (v < 0.0) { v = 0.0; } c.down_key = false; } actor::update(c, dt); } }; class enemyOne : public actor { public: enemyOne(float x, float y) : actor(math::vector2f(x, y)) { } void render() { transform(); glBegin(GL_TRIANGLES); glVertex3f(0.25f, 0.0f, -5.0f); glVertex3f(-.5f, 0.25f, -5.0f); glVertex3f(-.5f, -0.25f, -5.0f); glEnd(); end_transform(); } void update(controller& c, float dt) { if (c.left_key) { rho += pi / 9.0f * dt; c.left_key = false; } if (c.right_key) { rho -= pi / 9.0f * dt; c.right_key = false; } if (c.up_key) { v += .1f * dt; c.up_key = false; } if (c.down_key) { v -= .1f * dt; if (v < 0.0) { v = 0.0; } c.down_key = false; } actor::update(c, dt); } }; int APIENTRY WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, char* lpCmdLine, int nCmdShow ) { model m; controller control(m); srt::scheduler scheduler(33); srt::frame* model_frame = new srt::frame(scheduler.timer(), 0, 1, 2); srt::frame* render_frame = new srt::frame(scheduler.timer(), 1, 1, 2); model_frame->add(new model_module(m, control)); render_frame->add(new graphics_module(m)); scheduler.add(model_frame); scheduler.add(render_frame); blob* prime = new blob(0.0f, 0.0f); m.add(prime); m.set_prime(prime); enemyOne* primeTwo = new enemyOne(2.0f, 0.0f); m.add(primeTwo); m.set_prime(primeTwo); scheduler.start(); control.start(); return 0; } model.h #include <vector> #include "vec.h" const double pi = 3.14159265358979323; class controller; using math::vector2f; class actor { public: vector2f P; float theta; float v; float rho; actor(const vector2f& init_location) : P(init_location), rho(0.0), v(0.0), theta(0.0) { } virtual void render() = 0; virtual void update(controller&, float dt) { float v1 = v; float theta1 = theta + rho * dt; vector2f P1 = P + v1 * vector2f(cos(theta1), sin(theta1)); if (P1.x < -4.5f || P1.x > 4.5f) { P1.x = -P1.x; } if (P1.y < -4.5f || P1.y > 4.5f) { P1.y = -P1.y; } v = v1; theta = theta1; P = P1; } protected: void transform() { glPushMatrix(); glTranslatef(P.x, P.y, 0.0f); glRotatef(theta * 180.0f / pi, 0.0f, 0.0f, 1.0f); //Rotate about the z-axis } void end_transform() { glPopMatrix(); } }; class model { private: typedef std::vector<actor*> actor_vector; actor_vector actors; public: actor* _prime; model() { } void add(actor* a) { actors.push_back(a); } void set_prime(actor* a) { _prime = a; } void update(controller& control, float dt) { for (actor_vector::iterator i = actors.begin(); i != actors.end(); ++i) { (*i)->update(control, dt); } } void render() { for (actor_vector::iterator i = actors.begin(); i != actors.end(); ++i) { (*i)->render(); } } };

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