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  • How do I optimize searching for the nearest point?

    - by Rootosaurus
    For a little project of mine I'm trying to implement a space colonization algorithm in order to grow trees. The current implementation of this algorithm works fine. But I have to optimize the whole thing in order to make it generate faster. I work with 1 to 300K of random attraction points to generate one tree, and it takes a lot of time to compute and compare distances between attraction points and tree node in order to keep only the closest treenode for an attraction point. So I was wondering if some solutions exist (I know they must exist) in order to avoid the time loss looping on each tree node for each attraction point to find the closest... and so on until the tree is finished.

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  • Prevent collisions between mobs/npcs/units piloted by computer AI : How to avoid mobile obstacles?

    - by Arthur Wulf White
    Lets says we have character a starting at point A and character b starting at point B. character a is headed to point B and character b is headed to point A. There are several simple ways to find the path(I will be using Dijkstra). The question is, how do I take preventative action in the code to stop the two from colliding with one another? case2: Characters a and b start from the same point in different times. Character b starts later and is the faster of the two. How do I make character b walk around character a without going through it? case3:Lets say we have m such characters in each side and there is sufficient room to pass through without the characters overlapping with one another. How do I stop the two groups of characters from "walking on top of one another" and allow them pass around one another in a natural organic way. A correct answer would be any algorithm, that given the path to the destination and a list of mobile objects that block the path, finds an alternative path or stops without stopping all units when there is sufficient room to traverse.

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  • GLSL per pixel lighting with custom light type

    - by Justin
    Ok, I am having a big problem here. I just got into GLSL yesterday, so the code will be terrible, I'm sure. Basically, I am attempting to make a light that can be passed into the fragment shader (for learning purposes). I have four input values: one for the position of the light, one for the color, one for the distance it can travel, and one for the intensity. I want to find the distance between the light and the fragment, then calculate the color from there. The code I have gives me a simply gorgeous ring of light that get's twisted and widened as the matrix is modified. I love the results, but it is not even close to what I am after. I want the light to be moved with all of the vertices, so it is always in the same place in relation to the objects. I can easily take it from there, but getting that to work seems to be impossible with my current structure. Can somebody give me a few pointers (pun not intended)? Vertex shader: attribute vec4 position; attribute vec4 color; attribute vec2 textureCoordinates; varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; void main() { vec4 ECposition = gl_ModelViewMatrix * gl_Vertex; vec3 tnorm = normalize(vec3 (gl_NormalMatrix * gl_Normal)); fposition = ftransform(); gl_Position = fposition; gl_TexCoord[0] = gl_MultiTexCoord0; fposition = ECposition; lightPosition = vec4(0.0, 0.0, 5.0, 0.0) * gl_ModelViewMatrix * gl_Vertex; lightDistance = 5.0; lightIntensity = 1.0; lightColor = vec4(0.2, 0.2, 0.2, 1.0); } Fragment shader: varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; uniform sampler2D texture; void main() { float l_distance = sqrt((gl_FragCoord.x * lightPosition.x) + (gl_FragCoord.y * lightPosition.y) + (gl_FragCoord.z * lightPosition.z)); float l_value = lightIntensity / (l_distance / lightDistance); vec4 l_color = vec4(l_value * lightColor.r, l_value * lightColor.g, l_value * lightColor.b, l_value * lightColor.a); vec4 color; color = texture2D(texture, gl_TexCoord[0].st); gl_FragColor = l_color * color; //gl_FragColor = fposition; }

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  • XNA- Texturing problem, exporting model

    - by user1806687
    How,can I disable coloring when texture is applied, because right now the texture is being colored over. foreach (BasicEffect effect in mesh.Effects) { effect.TextureEnabled = textureApplied; if(textureApplied) effect.Texture = Texture2D.FromStream(GraphicsDevice,System.IO.File.OpenRead(texturePath)); else { effect.DiffuseColor = ti.DiffuseColor; effect.EmissiveColor = ti.EmissiveColor; } ... } mesh.Draw(); Also, is there any easy way for xna to export models? Or do I have to write my own?

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  • port opengl2.x to opengl 3.x

    - by user46759
    I'm trying to port opencloth example to OpenGL 3.x. I've mostly done it to the shaders but I'm not sure of this part : glEnableClientState(GL_VERTEX_ARRAY); glBindBuffer(GL_ARRAY_BUFFER, vboID); glVertexPointer(4, GL_FLOAT, 0,0); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glBindBuffer(GL_ARRAY_BUFFER, vboTexID); glTexCoordPointer(2, GL_FLOAT,0, 0); glEnableClientState(GL_NORMAL_ARRAY); glBindBuffer(GL_ARRAY_BUFFER, vboNormID); glNormalPointer(GL_FLOAT,sizeof(float)*4, 0); maybe glEnableVertexAttriArray somewhere ? any clue ? thanx edit : maybe something like that ? glEnableVertexAttribArray (2) ; // Ou glEnableVertexAttribArray (positionIndex) ; glBindBuffer(GL_ARRAY_BUFFER, vboTexID); glVertexAttribPointer (2, 2, GL_FLOAT, GL_FALSE, 0, 0) ; glEnableVertexAttribArray (3) ; // Ou glEnableVertexAttribArray (positionIndex) ; glBindBuffer(GL_ARRAY_BUFFER, vboNormID); glVertexAttribPointer (3, 4, GL_FLOAT, GL_FALSE, sizeof (float) * 4, 0) ;

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  • Constrained A* problem

    - by Ragekit
    I've got a little problem with an A* algorithm that I need to Constrained a little bit. Basically : I use an A* to find the shortest path between 2 randomly placed room in 3D space, and then build a corridor between them. The problem I found is that sometimes it makes chimney like corridors that are not ideal, so I constrict the A* so that if the last movement was up or down, you go sideways. Everything is fine, but in some corner cases, it fails to find a path (when there is obviously one). Like here between the blue and red dot : (i'm in unity btw, but i don't think it matters) Here is the code of the actual A* (a bit long, and some redundency) while(current != goal) { //add stair up / stair down foreach(Node<GridUnit> test in current.Neighbors) { if(!test.Data.empty && test != goal) continue; //bug at arrival; if(test == goal && penul !=null) { Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(currentDiff.y,0)) { //wanna drop on the last if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,to.Data.bounds.center)) { continue; } else { if(Mathf.Approximately(to.Data.bounds.center.x, current.Data.parentUnit.bounds.center.x) && Mathf.Approximately(to.Data.bounds.center.z, current.Data.parentUnit.bounds.center.z)) { continue; } } } } if(current.Data.parentUnit != null) { Vector3 previousDiff = current.Data.parentUnit.bounds.center - current.Data.bounds.center; Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(previousDiff.y,0)) { if(!Mathf.Approximately(currentDiff.y,0)) { //you wanna drop now : continue; } if(current.Data.parentUnit.parentUnit != null) { if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,current.Data.parentUnit.parentUnit.bounds.center)) { continue; }else { if(Mathf.Approximately(test.Data.bounds.center.x, current.Data.parentUnit.parentUnit.bounds.center.x) && Mathf.Approximately(test.Data.bounds.center.z, current.Data.parentUnit.parentUnit.bounds.center.z)) { continue; } } } } } g = current.Data.g + HEURISTIC(current.Data,test.Data); h = HEURISTIC(test.Data,goal.Data); f = g + h; if(open.Contains(test) || closed.Contains(test)) { if(test.Data.f > f) { //found a shorter path going passing through that point test.Data.f = f; test.Data.g = g; test.Data.h = h; test.Data.parentUnit = current.Data; } } else { //jamais rencontré test.Data.f = f; test.Data.h = h; test.Data.g = g; test.Data.parentUnit = current.Data; open.Add(test); } } closed.Add (current); if(open.Count == 0) { Debug.Log("nothingfound"); //nothing more to test no path found, stay to from; List<GridUnit> r = new List<GridUnit>(); r.Add(from.Data); return r; } //sort open from small to biggest travel cost open.Sort(delegate(Node<GridUnit> x, Node<GridUnit> y) { return (int)(x.Data.f-y.Data.f); }); //get the smallest travel cost node; Node<GridUnit> smallest = open[0]; current = smallest; open.RemoveAt(0); } //build the path going backward; List<GridUnit> ret = new List<GridUnit>(); if(penul != null) { ret.Insert(0,to.Data); } GridUnit cur = goal.Data; ret.Insert(0,cur); do{ cur = cur.parentUnit; ret.Insert(0,cur); } while(cur != from.Data); return ret; You see at the start of the foreach i constrict the A* like i said. If you have any insight it would be cool. Thanks

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  • Best way to solve tile drawing in 2D side scroller?

    - by TheCompBoy
    What i still can't figure out is which would be the more sane way / easier and faster way to draw the map on the screen.. I mean i will use many tiles for my maps in my side scroller.. But problem is should i make the maps in whole images like one .png file for each map (Example) or should i draw the tiles by code like a for loop in c++.. Which way is most recomended or where can i read about which way is the best.

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  • Figuring out what object is closer to a certain point?

    - by user1157885
    I'm trying to create fog of war, I have the visual effect created but I'm not sure how to deal with the hiding of other players if they're within the fog of war. So right now the thing I'm trying to do is if another player is hiding behind a wall then not to render that player. I was thinking of doing it by sending a ray in the direction of all the players, and then creating a list of all the obstacles that ray collides with and then trying to figure out if an obstacle was closer than the player in order to predict the distance. But then I realized I'm not really sure how to figure out if the obstacle is infact closer or not because I have to account for all the dimensions, so I'm kind of stuck. First of all is this approach the correct way to go about it and secondly how would I calculate if the obstacle was infact closer taking into account the X Y and Z. Thanks

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  • Is this the most effect simple way to display a moving image? SDL2

    - by user36324
    I've looked around for tutorials on SDL2, but there isnt many so I am curious i was messing around and is this an effective way to move an image. One problem is that it drags along the image to where it moves. #include "SDL.h" #include "SDL_image.h" int main(int argc, char* argv[]) { bool exit = false; SDL_Init(SDL_INIT_EVERYTHING); SDL_Window *win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN); SDL_Renderer *ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC); SDL_Surface *png = IMG_Load("character.png"); SDL_Rect src; src.x = 0; src.y = 0; src.w = 161; src.h = 159; SDL_Rect dest; dest.x = 50; dest.y = 50; dest.w = 161; dest.h = 159; SDL_Texture *tex = SDL_CreateTextureFromSurface(ren, png); SDL_FreeSurface(png); while(exit==false){ dest.x++; SDL_RenderClear(ren); SDL_RenderCopy(ren, tex, &src, &dest); SDL_RenderPresent(ren); } SDL_Delay(5000); SDL_DestroyTexture(tex); SDL_DestroyRenderer(ren); SDL_DestroyWindow(win); SDL_Quit(); }

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  • Recreating Doodle Jump in Canvas - Platforms spawning out of reach

    - by kushsolitary
    I have started to recreate Doodle Jump in HTML using Canvas. Here's my current progress. As you can see, if you play it for a few seconds, some platforms will be out of the player's reach. I don't know why is this happening. Here's the code which is responsible for the re-spawning of platforms. //Movement of player affected by gravity if(player.y > (height / 2) - (player.height / 2)) { player.y += player.vy; player.vy += gravity; } else { for(var i = 0; i < platforms.length; i++) { var p = platforms[i]; if(player.vy < 0) { p.y -= player.vy; player.vy += 0.08; } if(p.y > height) { position = 0; var h = p.y; platforms[i] = new Platform(); } if(player.vy >= 0) { player.y += player.vy; player.vy += gravity; } } } Also, here's the platform class. //Platform class function Platform(y) { this.image = new Image(); this.image.src = platformImg; this.width = 105; this.height = 25; this.x = Math.random() * (width - this.width); this.y = y || position; position += height / platformCount; //Function to draw it this.draw = function() { try { ctx.drawImage(this.image, this.x, this.y, this.width, this.height); } catch(e) {} }; } You can also see the whole code on the link I provided. Also, when a platform goes out of the view port, the jump animation becomes quirky. I am still trying to find out what's causing this but can't find any solution.

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  • Problem with sprite direction and rotation

    - by user2236165
    I have a sprite called Tool that moves with a speed represented as a float and in a direction represented as a Vector2. When I click the mouse on the screen the sprite change its direction and starts to move towards the mouseclick. In addition to that I rotate the sprite so that it is facing in the direction it is heading. However, when I add a camera that is suppose to follow the sprite so that the sprite is always centered on the screen, the sprite won't move in the given direction and the rotation isn't accurate anymore. This only happens when I add the Camera.View in the spriteBatch.Begin(). I was hoping anyone could maybe shed a light on what I am missing in my code, that would be highly appreciated. Here is the camera class i use: public class Camera { private const float zoomUpperLimit = 1.5f; private const float zoomLowerLimit = 0.1f; private float _zoom; private Vector2 _pos; private int ViewportWidth, ViewportHeight; #region Properties public float Zoom { get { return _zoom; } set { _zoom = value; if (_zoom < zoomLowerLimit) _zoom = zoomLowerLimit; if (_zoom > zoomUpperLimit) _zoom = zoomUpperLimit; } } public Rectangle Viewport { get { int width = (int)((ViewportWidth / _zoom)); int height = (int)((ViewportHeight / _zoom)); return new Rectangle((int)(_pos.X - width / 2), (int)(_pos.Y - height / 2), width, height); } } public void Move(Vector2 amount) { _pos += amount; } public Vector2 Position { get { return _pos; } set { _pos = value; } } public Matrix View { get { return Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) * Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) * Matrix.CreateTranslation(new Vector3(ViewportWidth * 0.5f, ViewportHeight * 0.5f, 0)); } } #endregion public Camera(Viewport viewport, float initialZoom) { _zoom = initialZoom; _pos = Vector2.Zero; ViewportWidth = viewport.Width; ViewportHeight = viewport.Height; } } And here is my Update and Draw-method: protected override void Update (GameTime gameTime) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; TouchCollection touchCollection = TouchPanel.GetState (); foreach (TouchLocation tl in touchCollection) { if (tl.State == TouchLocationState.Pressed || tl.State == TouchLocationState.Moved) { //direction the tool shall move towards direction = touchCollection [0].Position - toolPos; if (direction != Vector2.Zero) { direction.Normalize (); } //change the direction the tool is moving and find the rotationangle the texture must rotate to point in given direction toolPos += (direction * speed * elapsed); RotationAngle = (float)Math.Atan2 (direction.Y, direction.X); } } if (direction != Vector2.Zero) { direction.Normalize (); } //move tool in given direction toolPos += (direction * speed * elapsed); //change cameracentre to the tools position Camera.Position = toolPos; base.Update (gameTime); } protected override void Draw (GameTime gameTime) { graphics.GraphicsDevice.Clear (Color.Blue); spriteBatch.Begin (SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, Camera.View); spriteBatch.Draw (tool, new Vector2 (toolPos.X, toolPos.Y), null, Color.White, RotationAngle, originOfToolTexture, 1, SpriteEffects.None, 1); spriteBatch.End (); base.Draw (gameTime); }

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  • Rotating a Quad around it center

    - by Trixmix
    How can you rotate a quad around its center? This is what im trying to do but it aint working: GL11.glTranslatef(x-getWidth()/2, y-getHeight()/2, 0); GL11.glRotatef(30, 0.0f, 0.0f, 1.0f); GL11.glTranslatef(x+getWidth()/2, y+getHeight()/2, 0); DRAW my main problem is that it renders it off the screen.. draw code: GL11.glBegin(GL11.GL_QUADS); { GL11.glTexCoord2f(0, 0); GL11.glVertex2f(0, 0); GL11.glTexCoord2f(0, getTexture().getHeight()); GL11.glVertex2f(0, height); GL11.glTexCoord2f(getTexture().getWidth(), getTexture().getHeight()); GL11.glVertex2f(width,height); GL11.glTexCoord2f(getTexture().getWidth(), 0); GL11.glVertex2f(width,0); } GL11.glEnd();

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  • How do I create a big multiplayer world in UDK?

    - by Dorpe
    I want to create a big multiplayer world in UDK and I'm having a few difficulties. I created the biggest terrain possible but then any terrain related action I do takes forever. However, I've seen videos of people make same size terrain and working without a problem. My pc is strong enough, so maybe someone can tell me what I'm doing wrong. I want to make it even bigger then the biggest terrain size, so I was thinking of doing level streaming but then I read that streaming is working server side which means if I have a player on every terrain all terrains will still be loaded and I want to save as much memory possible so it will work well online. Thanks for any help you can give.

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  • Ad Service That Lets You Choose Your Ad, and Then Some [on hold]

    - by user3634450
    I'm trying to build an app for both Android and/or iOS where part of the gameplay actually involves ads as a texture. I need to be able to choose which ads I would like to use. I need to be able to be able to identify the ads (which if I can choose which ads show up in the app shouldn't be that hard). I need to be able to swap in and out new ads on what could possibly be a daily basis (and don't want to have to update the app to do it). And as if that wasn't too needy a list, I need to be able to load 50 ads from the pool of ads I deem fit, all to each and every user of the app at least every couple of days. I don't care if the ads pay, I'm not looking for clicks, but I don't want to have to make 50 fake ads every couple of days, from an "artistic" level I don't want the content to feel phony or fake, and I don't really have a way to load content to each user via some internet source (if anyone could name one that would be great). I'm not sure what kind of ad provider would like or even approve of this, in fact just what I've described might be against Google Play's or iTunes' content developer policies, but if anyone could give me any advice to steer me in the right direction it would be greatly appreciated, thank you.

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  • Point in Polygon, Ray Method: ending infinite line

    - by user2878528
    Having a bit of trouble with point in polygon collision detection using the ray method i.e. http://en.wikipedia.org/wiki/Point_in_polygon My problem is I need to give an end to the infinite line created. As with this infinite line I always get an even number of intersections and hence an invalid result. i.e. ignore or intersection to the right of the point being checked what I have what I want My current code based of Mecki awesome response for (int side = 0; side < vertices.Length; side++) { // Test if current side intersects with ray. // create infinite line // See: http://en.wikipedia.org/wiki/Linear_equation a = end_point.Y - start_point.Y; b = start_point.X - end_point.X; c = end_point.X * start_point.Y - start_point.X * end_point.Y; //insert points of vector d2 = a * vertices[side].Position.X + b * vertices[side].Position.Y + c; if (side - 1 < 0) d1 = a * vertices[vertices.Length - 1].Position.X + b * vertices[vertices.Length - 1].Position.Y + c; else d1 = a * vertices[side-1].Position.X + b * vertices[side-1].Position.Y + c; // If points have opposite sides, intersections++; if (d1 > 0 && d2 < 0 ) intersections++; if (d1 < 0 && d2 > 0 ) intersections++; } //if intersections odd inside = true if ((intersections % 2) == 1) inside = true; else inside = false;

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  • Possible to pass pygame data to memory map block?

    - by toozie21
    I am building a matrix out of addressable pixels and it will be run by a Pi (over the ethernet bus). The matrix will be 75 pixels wide and 20 pixels tall. As a side project, I thought it would be neat to run pong on it. I've seen some python based pong tutorials for Pi, but the problem is that they want to pass the data out to a screen via pygame.display function. I have access to pass pixel information using a memory map block, so is there anyway to do that with pygame instead of passing it out the video port? In case anyone is curious, this was the pong tutorial I was looking at: Pong Tutorial

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  • Realistic Jumping

    - by Seth Taddiken
    I want to make the jumping that my character does more realistic. This is what I've tried so far but it doesn't seem very realistic when the player jumps. I want it to jump up at a certain speed then slow down as it gets to the top then eventually stopping (for about one frame) and then slowly going back down but going faster and faster as it goes back down. I've been trying to make the speed at which the player jumps up slow down by one each frame then become negative and go down faster... but it doesn't work very well public bool isPlayerDown = true; public bool maxJumpLimit = false; public bool gravityReality = false; public bool leftWall = false; public bool rightWall = false; public float x = 76f; public float y = 405f; if (Keyboard.GetState().IsKeyDown(up) && this.isPlayerDown == true && this.y <= 405f) { this.isPlayerDown = false; } if (this.isPlayerDown == false && this.maxJumpLimit == false) { this.y = this.y - 6; } if (this.y <= 200) { this.maxJumpLimit = true; } if (this.isPlayerDown == true) { this.y = 405f; this.isPlayerDown = true; this.maxJumpLimit = false; } if (this.gravityReality == true) { this.y = this.y + 2f; this.gravityReality = false; } if (this.maxJumpLimit == true) { this.y = this.y + 2f; this.gravityReality = true; } if (this.y > 405f) { this.isPlayerDown = true; }

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  • In 3D camera math, calculate what Z depth is pixel unity for a given FOV

    - by badweasel
    I am working in iOS and OpenGL ES 2.0. Through trial and error I've figured out a frustum to where at a specific z depth pixels drawn are 1 to 1 with my source textures. So 1 pixel in my texture is 1 pixel on the screen. For 2d games this is good. Of course it means that I also factor in things like the size of the quad and the size of the texture. For example if my sprite is a quad 32x32 pixels. The quad size is 3.2 units wide and tall. And the texcoords are 32 / the size of the texture wide and tall. Then the frustum is: matrixFrustum(-(float)backingWidth/frustumScale,(float)backingWidth/frustumScale, -(float)backingHeight/frustumScale, (float)backingHeight/frustumScale, 40, 1000, mProjection); Where frustumScale is 800 for a retina screen. Then at a distance of 800 from camera the sprite is pixel for pixel the same as photoshop. For 3d games sometimes I still want to be able to do this. But depending on the scene I sometimes need the FOV to be different things. I'm looking for a way to figure out what Z depth will achieve this same pixel unity for a given FOV. For this my mProjection is set using: matrixPerspective(cameraFOV, near, far, (float)backingWidth / (float)backingHeight, mProjection); With testing I found that at an FOV of 45.0 a Z of 38.5 is very close to pixel unity. And at an FOV of 30.0 a Z of 59.5 is about right. But how can I calculate a value that is spot on? Here's my matrixPerspecitve code: void matrixPerspective(float angle, float near, float far, float aspect, mat4 m) { //float size = near * tanf(angle / 360.0 * M_PI); float size = near * tanf(degreesToRadians(angle) / 2.0); float left = -size, right = size, bottom = -size / aspect, top = size / aspect; // Unused values in perspective formula. m[1] = m[2] = m[3] = m[4] = 0; m[6] = m[7] = m[12] = m[13] = m[15] = 0; // Perspective formula. m[0] = 2 * near / (right - left); m[5] = 2 * near / (top - bottom); m[8] = (right + left) / (right - left); m[9] = (top + bottom) / (top - bottom); m[10] = -(far + near) / (far - near); m[11] = -1; m[14] = -(2 * far * near) / (far - near); } And my mView is set using: lookAtMatrix(cameraPos, camLookAt, camUpVector, mView); * UPDATE * I'm going to leave this here in case anyone has a different solution, can explain how they do it, or why this works. This is what I figured out. In my system I use a 10th scale unit to pixels on non-retina displays and a 20th scale on retina displays. The iPhone is 640 pixels wide on retina and 320 pixels wide on non-retina (obsolete). So if I want something to be the full screen width I divide by 20 to get the OpenGL unit width. Then divide that by 2 to get the left and right unit position. Something 32 units wide centered on the screen goes from -16 to +16. Believe it or not I have an excel spreadsheet do all this math for me and output all the vertex data for my sprite sheet. It's an arbitrary thing I made up to do .1 units = 1 non-retina pixel or 2 retina pixels. I could have made it .01 units = 2 pixels and someday I might switch to that. But for now it's the other. So the width of the screen in units is 32.0, and that means the left most pixel is at -16.0 and the right most is at 16.0. After messing a bit I figured out that if I take the [0] value of an identity modelViewProjection matrix and multiply it by 16 I get the depth required to get 1:1 pixels. I don't know why. I don't know if the 16 is related to the screen size or just a lucky guess. But I did a test where I placed a sprite at that calculated depth and varied the FOV through all the valid values and the object stays steady on screen with 1:1 pixels. So now I'm just calculating the unityDepth that way. If someone gives me a better answer I'll checkmark it.

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  • infer half vector length in BRDF

    - by cician
    it's my first question on stack. Is it possible to infer length of the half angle vector for specular lighting from N·L and N·V without the whole view and light vectors? I may be completely off-track, but I have this gut feeling it's possible... Why? I'm working on a skin shader and I'm already doing one texture lookup with N·L+N·E and one texture lookup for specular with N·H+N·V. The latter one can be transformed into N·L+N·E lookup if only I had the half vector length. Doing so could simplify the shader a bit and move some operations into the pre-computed lookup texture. It would make a huge difference since I'm trying to squeeze as much functionality as possible to a single pass mobile version so instruction count matters. Thanks.

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  • Accounting for waves when doing planar reflections

    - by CloseReflector
    I've been studying Nvidia's examples from the SDK, in particular the Island11 project and I've found something curious about a piece of HLSL code which corrects the reflections up and down depending on the state of the wave's height. Naturally, after examining the brief paragraph of code: // calculating correction that shifts reflection up/down according to water wave Y position float4 projected_waveheight = mul(float4(input.positionWS.x,input.positionWS.y,input.positionWS.z,1),g_ModelViewProjectionMatrix); float waveheight_correction=-0.5*projected_waveheight.y/projected_waveheight.w; projected_waveheight = mul(float4(input.positionWS.x,-0.8,input.positionWS.z,1),g_ModelViewProjectionMatrix); waveheight_correction+=0.5*projected_waveheight.y/projected_waveheight.w; reflection_disturbance.y=max(-0.15,waveheight_correction+reflection_disturbance.y); My first guess was that it compensates for the planar reflection when it is subjected to vertical perturbation (the waves), shifting the reflected geometry to a point where is nothing and the water is just rendered as if there is nothing there or just the sky: Now, that's the sky reflecting where we should see the terrain's green/grey/yellowish reflection lerped with the water's baseline. My problem is now that I cannot really pinpoint what is the logic behind it. Projecting the actual world space position of a point of the wave/water geometry and then multiplying by -.5f, only to take another projection of the same point, this time with its y coordinate changed to -0.8 (why -0.8?). Clues in the code seem to indicate it was derived with trial and error because there is redundancy. For example, the author takes the negative half of the projected y coordinate (after the w divide): float waveheight_correction=-0.5*projected_waveheight.y/projected_waveheight.w; And then does the same for the second point (only positive, to get a difference of some sort, I presume) and combines them: waveheight_correction+=0.5*projected_waveheight.y/projected_waveheight.w; By removing the divide by 2, I see no difference in quality improvement (if someone cares to correct me, please do). The crux of it seems to be the difference in the projected y, why is that? This redundancy and the seemingly arbitrary selection of -.8f and -0.15f lead me to conclude that this might be a combination of heuristics/guess work. Is there a logical underpinning to this or is it just a desperate hack? Here is an exaggeration of the initial problem which the code fragment fixes, observe on the lowest tessellation level. Hopefully, it might spark an idea I'm missing. The -.8f might be a reference height from which to deduce how much to disturb the texture coordinate sampling the planarly reflected geometry render and -.15f might be the lower bound, a security measure.

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  • Why isnt my data persisting with nskeyedarchiver?

    - by aking63
    Im just working on what should be the "finishing touches" of my first iPhone game. For some reason, when I save with NSKeyedArchiver/Unarchiver, the data seems to load once and then gets lost or something. Here's what I've been able to deduce: When I save in this viewController, pop to the previous one, and then push back into this one, the data is saved and prints as I want it to. But when I save in this viewController, then push a new one and pop back into this one, the data is lost. Any idea why this might be happening? Do I have this set up all wrong? I copied it from a book months ago. Here's the methods I use to save and load. - (void) saveGameData { NSLog(@"LS:saveGameData"); // SAVE DATA IMMEDIATELY NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *gameStatePath = [documentsDirectory stringByAppendingPathComponent:@"gameState.dat"]; NSMutableData *gameSave= [NSMutableData data]; NSKeyedArchiver *encoder = [[NSKeyedArchiver alloc] initForWritingWithMutableData:gameSave]; [encoder encodeObject:categoryLockStateArray forKey:kCategoryLockStateArray]; [encoder encodeObject:self.levelsPlist forKey:@"levelsPlist"]; [encoder finishEncoding]; [gameSave writeToFile:gameStatePath atomically:YES]; NSLog(@"encoded catLockState:%@",categoryLockStateArray); } - (void) loadGameData { NSLog(@"loadGameData"); // If there is a saved file, perform the load NSMutableData *gameData = [NSData dataWithContentsOfFile:[[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"gameState.dat"]]; // LOAD GAME DATA if (gameData) { NSLog(@"-Loaded Game Data-"); NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:gameData]; self.levelsPlist = [unarchiver decodeObjectForKey:@"levelsPlist"]; categoryLockStateArray = [unarchiver decodeObjectForKey:kCategoryLockStateArray]; NSLog(@"decoded catLockState:%@",categoryLockStateArray); } // CREATE GAME DATA else { NSLog(@"-Created Game Data-"); self.levelsPlist = [[NSMutableDictionary alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:kLevelsPlist ofType:@"plist"]]; } if (!categoryLockStateArray) { NSLog(@"-Created categoryLockStateArray-"); categoryLockStateArray = [[NSMutableArray alloc] initWithCapacity:[[self.levelsPlist allKeys] count]]; for (int i=0; i<[[self.levelsPlist allKeys] count]; i++) { [categoryLockStateArray insertObject:[NSNumber numberWithBool:FALSE] atIndex:i]; } } // set the properties of the categories self.categoryNames = [self.levelsPlist allKeys]; NUM_CATEGORIES = [self.categoryNames count]; thisCatCopy = [[NSMutableDictionary alloc] initWithDictionary:[[levelsPlist objectForKey:[self.categoryNames objectAtIndex:pageControl.currentPage]] mutableCopy]]; NUM_FINISHED = [[thisCatCopy objectForKey:kNumLevelsBeatenInCategory] intValue]; }

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  • Scene transitions

    - by Mars
    It's my first time working with actual scenes/states, aka DrawableGameComponents, which work separate from one another. I'm now wondering what's the best way to make transitions between them, and how to affect them from other scenes. Lets say I wanted to "push" one screen to the right, with another one coming in at the same time. Naturally I'd have to keep drawing both, until the transition is complete. And I'd have to adjust the coordinates I'm drawing at while doing it. Is there a way around specifically handling this special case in every single scene? Or of I wanted to fade one into the other. Basically the question stays the same, how would you do that without having to handle it in every single scene? While writing this I'm realizing it will be the same thing for all kinds of transitions. Maybe a central Draw method in the manager could be a solution, where parameters and effects are applied when necessary. But this wouldn't work if objects that are drawn have their own method, and aren't drawn within the scene, or if an effect has to be applied to the whole scene. That means, maybe scenes have to be drawn to their own rendertarget? That way one call to the base class after the normal drawing could be enough, to apply the effects, while drawing it to the main render target. But I once heard there are problems when switching from target to target, back and forth. So is that even a viable option? As you can see, I have some basic ideas how it might work... but nothing specific. I'd like to learn what's the common way to achieve such things, a general way to apply all kinds of transitions.

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  • Wall avoidance steering

    - by Vodemki
    I making a small steering simulator using the reynolds boid algorythm. Now I want to add a wall avoidance feature. My walls are in 3D and defined using two points like that: ---------. P2 | | P1 .--------- My agents have a velocity, a position, etc... Could you tell me how to make avoidance with my agents ? Vector2D ReynoldsSteeringModel::repulsionFromWalls() { Vector2D force; vector<Wall *> wallsList = walls(); Point2D pos = self()->position(); Vector2D velocity = self()->velocity(); for (unsigned i=0; i<wallsList.size(); i++) { //TODO } return force; } Then I use all the forces returned by my boid functions and I apply it to my agent. I just need to know how to do that with my walls ? Thanks for your help.

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  • LWJGL GL_QUADS texture artifact

    - by Dajgoro Labinac
    I managed to get working lwjgl in Java, and i loaded a test image(tv test card), but i keep getting weird artifacts outside the image. Image link: http://tinypic.com/r/vhv9g/6 Code: glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex2i(10, 10); glTexCoord2f(1, 0); glVertex2i(500, 10); glTexCoord2f(1, 1); glVertex2i(500, 500); glTexCoord2f(0, 1); glVertex2i(10, 500); glEnd(); What could be the cause?

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  • Cocos2d Box2d contact listener call different method in collided object

    - by roma86
    I have the building object, wen it hit with other, i want to call some method inside it. Building.mm -(void)printTest { NSLog(@"printTest method work correctly"); } in my ContactListener i trying to call it so: ContactListener.mm #import "ContactListener.h" #import "Building.h" void ContactListener::BeginContact(b2Contact* contact) { b2Body* bodyA = contact->GetFixtureA()->GetBody(); b2Body* bodyB = contact->GetFixtureB()->GetBody(); Building *buildA = (Building *)bodyA->GetUserData(); Building *buildB = (Building *)bodyB->GetUserData(); if (buildB.tag == 1) { NSLog(@"tag == 1"); } if (buildA.tag == 2) { NSLog(@"tag == 2"); [buildA printTest]; } } NSLog(@"tag == 2"); work correctly, but [buildA printTest]; get error Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CCSprite printTest]: unrecognized selector sent to instance 0x18595f0' Obviously I'm referring to the wrong object. How i can get different method and property in contacted objects from contactlistener class? Thanks.

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