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• Pathfinding and BSP with Box2D

  - by Amplify91

  I'm looking into implementing AI in my 2D side-scrolling platformer, and I'm looking into using algorithms such as A*. For many kinds of pathfinding, we need some sort of grid or systems of nodes or polygon areas. My problem is that I am using Box2d for physics and I am not sure how best to create a structure that my AI can use besides placing individual nodes manually (something I really want to avoid) and using some sort of steering behavior. My level design is tile-based with each tile being about half of the height/width of my main character. The tiles are not all square (some are sloped). I'd like to have a system that can see what the terrain looks like for pathfinding and also keep track of the positions of other actors such as enemies. I'd like to avoid directly placing any nodes into my level design except for possible endpoints or goals. This question is related: How do you do AI path following within a 2d physics engine like farseer/box2d?, but it doesn't specify what kind of structure I could use instead of a list of nodes. I'm looking for some kind of grid or type of BSP that I can query for algorithms like A*.

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• How to create a 3D world with 2D sprites similar to Ragnorak online?

  - by Romoku

  As far as I know Ragnorak Online is a 3D game world with 2D sprites overlayed. I would like to use this style in a game I am making in Unity, so I would like the player to be able to select little square tiles on the terrain. There are a couple routes I could take such as using a bunch of cubic polygons and linking them together or using one big map. The former approach doesn't seem to make any sense if the world is not flat as polygons wouldn't be reused often. The goal is to break down a 3D polygon into tiles which is heard to wrap my head around. I believe using something like an interval tree or array would be appropriate to store the rectangle grid, but how would I display a rectangle around the selection the player has his mouse over on the polygon terrain itself? Here is a screenshot. Here is a gameplay video. Here is the camera usage.

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• Hero/Character sprite size in comparison to tile size?

  - by Kid

  So I'm making this simple platformer where the Hero is 16x16 in size, but also, the tile size is 16x16. Which sounds fine right? But my game window/world is 800x416, which makes the Hero is really really tiny in comparison. This really surprised me, but given Ive never made a platformer before it is also a new discovery. Is there a rule set for scale in platformer games? I'd like to have my game window remain the size it is (800x416), cause the game involves large levels. But how big should my hero be? I hope I was clear with the question, and I appreciate any insight. Thanks

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• Arrive steering behavior

  - by dbostream

  I bought a book called Programming game AI by example and I am trying to implement the arrive steering behavior. The problem I am having is that my objects oscillate around the target position; after oscillating less and less for awhile they finally come to a stop at the target position. Does anyone have any idea why this oscillating behavior occur? Since the examples accompanying the book are written in C++ I had to rewrite the code into C#. Below is the relevant parts of the steering behavior: private enum Deceleration { Fast = 1, Normal = 2, Slow = 3 } public MovingEntity Entity { get; private set; } public Vector2 SteeringForce { get; private set; } public Vector2 Target { get; set; } public Vector2 Calculate() { SteeringForce.Zero(); SteeringForce = SumForces(); SteeringForce.Truncate(Entity.MaxForce); return SteeringForce; } private Vector2 SumForces() { Vector2 force = new Vector2(); if (Activated(BehaviorTypes.Arrive)) { force += Arrive(Target, Deceleration.Slow); if (!AccumulateForce(force)) return SteeringForce; } return SteeringForce; } private Vector2 Arrive(Vector2 target, Deceleration deceleration) { Vector2 toTarget = target - Entity.Position; double distance = toTarget.Length(); if (distance > 0) { //because Deceleration is enumerated as an int, this value is required //to provide fine tweaking of the deceleration.. double decelerationTweaker = 0.3; double speed = distance / ((double)deceleration * decelerationTweaker); speed = Math.Min(speed, Entity.MaxSpeed); Vector2 desiredVelocity = toTarget * speed / distance; return desiredVelocity - Entity.Velocity; } return new Vector2(); } private bool AccumulateForce(Vector2 forceToAdd) { double magnitudeRemaining = Entity.MaxForce - SteeringForce.Length(); if (magnitudeRemaining <= 0) return false; double magnitudeToAdd = forceToAdd.Length(); if (magnitudeToAdd > magnitudeRemaining) magnitudeToAdd = magnitudeRemaining; SteeringForce += Vector2.NormalizeRet(forceToAdd) * magnitudeToAdd; return true; } This is the update method of my objects: public void Update(double deltaTime) { Vector2 steeringForce = Steering.Calculate(); Vector2 acceleration = steeringForce / Mass; Velocity = Velocity + acceleration * deltaTime; Velocity.Truncate(MaxSpeed); Position = Position + Velocity * deltaTime; } If you want to see the problem with your own eyes you can download a minimal example here. Thanks in advance.

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• What is the best way to code the XNA Game Server for FPS game?

  - by AgentFire

  I'm writing a FPS XNA game. It gonna be multiplayer so I came up with following: I'm making two different assemblies — one for the game logic and the second for drawing it and the game irrelevant stuff (like rocket trails). The type of the connection is client-server (not peer-to-peer), so every client at first connects to the server and then the game begins. I'm completly decided to use XNA.Framework.Game class for the clients to run their game in window (or fullscreen) and the GameComponent/DrawableGameComponent classes to store the game objects and update&draw them on each frame. Next, I want to get the answer to the question: What should I do on the server side? I got few options: Create my own Game class on the server, which will process all the game logic (only, no graphics). The reason why I am not using the standart Game class is when I call Game.Run() the white window appears and I cant figure out how to get rid of it. Use somehow the original XNA's Game class, which is already has the GameComponent collection and Update event (60 times per second, just what I need). UPDATE: I got more questions: First, what socket mode should I use? TCP or UDP? And how to actually let the client know that this packet is meant to be processed after that one? Second, if I is going to use exacly GameComponent class for the game objects which is stored and process on the server, how to make them to be drawn on the client? Inherit them (while they are combined to an assembly)? Something else?

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• Physics in carrom like game using cocos2d + Box2D

  - by Raj

  I am working on carrom like game using cocos2d + Box2D. I set world gravity(0,0), want gravity in z-axis. I set following values for coin and striker body: Coin body (circle with radius - 15/PTM_RATIO): density = 20.0f; friction = 0.4f; restitution = 0.6f; Striker body (circle with radius - 15/PTM_RATIO): density = 25.0f; friction = 0.6f; restitution = 0.3f; Output is not smooth. When I apply ApplyLinearImpulse(force,position) the coin movement looks like floating in the air - takes too much time to stop. What values for coin and striker make it look like real carrom?

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• How can I generate a view or projection matrix for OpenGL 3.+

  - by Ken

  I'm transitioning from OpenGL 2 to OpenGL 3.+ and to GLSL 1.5. I'm trying to avoid using the deprecated features. My question how do we now generate the view or projection matrix. I was using the matrix stack to calculate the projection matrix for me; GLfloat ptr[16]; gluPerspective(...); glGetFloatv(GL_MODELVIEW_MATRIX, ptr); //then pass ptr via a uniform to the shader But obviously the matrix stack is deprecated. So this approach is not the best an option going forward. I have the 'Red Book', 7th ed, which covers 3.0 & 3.1 and it still uses the deprecated matrix functions in it's examples. I could write some utility-code myself to generate the matrices. But I don't want to re-invent this particular wheel, especially when this functionality is required for every 3D graphics program. What is the accepted way to generate world,view & projection matrices for OpenGL? Is there an emerging 'standard' library for this? Or is there some other hidden (to me) functionality in OpenGL/GLSL which I have overlooked?

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• Center directional light shadow to the cameras eye

  - by Caesar

  I'm currently drawing my directional light shadow using this view and projection: XMFLOAT3 dir((float)pitch, (float)yaw, (float)roll); XMFLOAT3 center(0.0f, 0.0f, 0.0f); XMVECTOR lightDir = XMLoadFloat3(&dir); XMVECTOR lightPos = radius * lightDir; XMVECTOR targetPos = XMLoadFloat3(&center); XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f); XMMATRIX V = XMMatrixLookAtLH(lightPos, targetPos, up); // This is the view // Transform bounding sphere to light space. XMFLOAT3 sphereCenterLS; XMStoreFloat3(&sphereCenterLS, XMVector3TransformCoord(targetPos, V)); // Ortho frustum in light space encloses scene. float l = sphereCenterLS.x - radius; float b = sphereCenterLS.y - radius; float n = sphereCenterLS.z - radius; float r = sphereCenterLS.x + radius; float t = sphereCenterLS.y + radius; float f = sphereCenterLS.z + radius; XMMATRIX P = XMMatrixOrthographicOffCenterLH(l, r, b, t, n, f); // This is the projection Which works prefect if the center of my scene is at 0.0, 0.0, 0.0. What I would like to do is move the center of the scene relative to the cameras position. How can I do that?

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• Importing Models from Maya to OpenGL

  - by Mert Toka

  I am looking for ways to import models to my game project. I am using Maya as modelling software, and GLUT for windowing of my game. I found this great parser, it imports all the textures and normal vectors, but it is compatible with .obj files of 3dsMAX. I tried to use it with Maya obj's, and it turned out that Maya's obj files are a bit different from former one, thus it cannot parse them. If you know any way to convert Maya obj files to 3dsMax obj files, that would be acceptable as well as a new parser for Maya obj files.

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• Shadows shimmer when camera moves

  - by Chad Layton

  I've implemented shadow maps in my simple block engine as an exercise. I'm using one directional light and using the view volume to create the shadow matrices. I'm experiencing some problems with the shadows shimmering when the camera moves and I'd like to know if it's an issue with my implementation or just an issue with basic/naive shadow mapping itself. Here's a video: http://www.youtube.com/watch?v=vyprATt5BBg&feature=youtu.be Here's the code I use to create the shadow matrices. The commented out code is my original attempt to perfectly fit the view frustum. You can also see my attempt to try clamping movement to texels in the shadow map which didn't seem to make any difference. Then I tried using a bounding sphere instead, also to no apparent effect. public void CreateViewProjectionTransformsToFit(Camera camera, out Matrix viewTransform, out Matrix projectionTransform, out Vector3 position) { BoundingSphere cameraViewFrustumBoundingSphere = BoundingSphere.CreateFromFrustum(camera.ViewFrustum); float lightNearPlaneDistance = 1.0f; Vector3 lookAt = cameraViewFrustumBoundingSphere.Center; float distanceFromLookAt = cameraViewFrustumBoundingSphere.Radius + lightNearPlaneDistance; Vector3 directionFromLookAt = -Direction * distanceFromLookAt; position = lookAt + directionFromLookAt; viewTransform = Matrix.CreateLookAt(position, lookAt, Vector3.Up); float lightFarPlaneDistance = distanceFromLookAt + cameraViewFrustumBoundingSphere.Radius; float diameter = cameraViewFrustumBoundingSphere.Radius * 2.0f; Matrix.CreateOrthographic(diameter, diameter, lightNearPlaneDistance, lightFarPlaneDistance, out projectionTransform); //Vector3 cameraViewFrustumCentroid = camera.ViewFrustum.GetCentroid(); //position = cameraViewFrustumCentroid - (Direction * (camera.FarPlaneDistance - camera.NearPlaneDistance)); //viewTransform = Matrix.CreateLookAt(position, cameraViewFrustumCentroid, Up); //Vector3[] cameraViewFrustumCornersWS = camera.ViewFrustum.GetCorners(); //Vector3[] cameraViewFrustumCornersLS = new Vector3[8]; //Vector3.Transform(cameraViewFrustumCornersWS, ref viewTransform, cameraViewFrustumCornersLS); //Vector3 min = cameraViewFrustumCornersLS[0]; //Vector3 max = cameraViewFrustumCornersLS[0]; //for (int i = 1; i < 8; i++) //{ // min = Vector3.Min(min, cameraViewFrustumCornersLS[i]); // max = Vector3.Max(max, cameraViewFrustumCornersLS[i]); //} //// Clamp to nearest texel //float texelSize = 1.0f / Renderer.ShadowMapSize; //min.X -= min.X % texelSize; //min.Y -= min.Y % texelSize; //min.Z -= min.Z % texelSize; //max.X -= max.X % texelSize; //max.Y -= max.Y % texelSize; //max.Z -= max.Z % texelSize; //// We just use an orthographic projection matrix. The sun is so far away that it's rays are essentially parallel. //Matrix.CreateOrthographicOffCenter(min.X, max.X, min.Y, max.Y, -max.Z, -min.Z, out projectionTransform); } And here's the relevant part of the shader: if (CastShadows) { float4 positionLightCS = mul(float4(position, 1.0f), LightViewProj); float2 texCoord = clipSpaceToScreen(positionLightCS) + 0.5f / ShadowMapSize; float shadowMapDepth = tex2D(ShadowMapSampler, texCoord).r; float distanceToLight = length(LightPosition - position); float bias = 0.2f; if (shadowMapDepth < (distanceToLight - bias)) { return float4(0.0f, 0.0f, 0.0f, 0.0f); } } The shimmer is slightly better if I drastically reduce the view volume but I think that's mostly just because the texels become smaller and it's harder to notice them flickering back and forth. I'd appreciate any insight, I'd very much like to understand what's going on before I try other techniques.

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• How are buttons made to be clicked?

  - by Johnny

  I just want to ask a general question. According to that answer, Ill continue thinking. You know in games there are lots of clickable items. Play button, exit, comboboxes maybe etc. My question is are those buttons drawn in same canvas with background and all other things, or for every different thing there is another canvas object? My question is about for general. Im not asking about a specific game, im asking how they are made generally. Im planning to start a game on Android, and Im confused actually how to design buttons, and other object. Probably Im going to use View/SurfaceView for now. I don't have much experience with OpenGL yet. Thanks in advance.

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• What tools should I consider if my aim is to make a game available to as many platforms as possible?

  - by Kenji Kina

  We're planning on developing a 2D, grid-based puzzle game, and although it's still very early in the planning stages, we'd like to make our decisions well from the beginning. Our strategy will be to make the game available to as many platforms as possible, for example PCs (Windows, Mac and/or Linux), mobile phones (iPhone and/or Android based phones), game consoles (XBLA and/or PSN) PC will have an emphasis, but I believe that's the most flexible platform so that shouldn't be a problem. So, what programming language, game engine, frameworks and all around tools would be best suited for our goal? P.S.: I'm betting a set of tools won't cover ALL of them, and that there will still be some kind of "translating" effort for some platforms, but we'd like to know what the most far reaching are.

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• Making a surface transparent from blackness of texture

  - by Dan the Man

  I am making a "halo" shader in unity using GLSL. And I've come to a roadblock. What I need to do is take a texture, like the following, and make it transparent according to the darkness of it. And I don't want a cutout, because that cuts it off at a hard edge. This line of code doesn't seem to work. gl_FragColor = texture2D( vec4( _MainTex.r, _MainTex.g, _MainTex.b, _MainTex.a), vec2(textureCoordinates));

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• Cropping a line (laser beam) in XNA

  - by electroflame

  I have a laser sprite that I wish to crop. I want to crop it so when it collides with an item, I can calculate the distance between the starting point, and the ending point, and only draw that. This eliminates the "overdraw" of a laser drawing past an item. Essentially, I'm trying to crop a line, but also keep that line "attached" to the nose of my ship. The line should not be drawn past the nose of my ship, that should be the starting point. There is no rotation to worry about. Currently, I thought that doing this through SpriteBatch would be best. This is my current Spritebatch code: spriteBatch.Draw(Laser.sprite, new Rectangle((int)Laser.position.X, (int)Laser.position.Y, Laser.sprite.Width, LaserHeight), new Rectangle(0, 0, (int)(Laser.sprite.Width), LaserHeight), new Color(255, 255, 255, (byte)MathHelper.Clamp(Laser.Alpha, 0, 255)), Laser.rotation, new Vector2(Laser.sprite.Width/2, LaserHeight/2), SpriteEffects.None, 0); But this doesn't quite work. It does only draw part of the sprite, but when LaserHeight is incremented, it lengthens the line in both ways! I believe this is due to some stupid error on my part with the Origin of the draw. Quick recap: I need to have my laser sprite drawn with the bottom of it at the nose of my ship, and then use LaserHeight to crop the image so only part of it is drawn. I have a feeling my explanation is a bit...lacking. So if you require more information, please say so and I will try to provide more information. Thanks in advance!

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• how to do partial updates in OpenGL?

  - by Will

  It is general wisdom that you redraw the entire viewport on each frame. I would like to use partial updates; what are the various ways can do that, and what are their pros, cons and relative performance? (Using textures, FBOs, the accumulator buffer, any kind of scissors that can affect swapbuffers etc?) A scenario: a scene with a fair few thousand visible trees; although the textures are mipmapped and they are drawn via VBOs roughly front-to-back with so on, its still a lot of polys. Would streaming a single screen-sized texture be better than throwing them at the screen every frame? You'd have to redraw and recapture them only on camera movement or as often as your wind model updates or whatever, which need not be every frame.

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• How do I choose the scaling factor of a 3D game world?

  - by concept3d

  I am making a 3D tank game prototype with some physics simulation, am using C++. One of the decisions I need to make is the scale of the game world in relation to reality. For example, I could consider 1 in-game unit of measurement to correspond to 1 meter in reality. This feels intuitive, but I feel like I might be missing something. I can think of the following as potential problems: 3D modelling program compatibility. (?) Numerical accuracy. (Does this matter?) Especially at large scales, how games like Battlefield have huge maps: How don't they lose numerical accuracy if they use 1:1 mapping with real world scale, since floating point representation tend to lose more precision with larger numbers (e.g. with ray casting, physics simulation)? Gameplay. I don't want the movement of units to feel slow or fast while using almost real world values like -9.8 m/s^2 for gravity. (This might be subjective.) Is it ok to scale up/down imported assets or it's best fit with a world with its original scale? Rendering performance. Are large meshes with the same vertex count slower to render? I'm wondering if I should split this into multiple questions...

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• How to get all keys values of the player prefs in unity [java script ]

  - by Akari

  in the first test game I've developed if the player passed all the levels and win , he must enter his name ... so his name and his score will be stored in a player prefs : and there is another scene that displays the names and scores of all the user passed the game : I've searched from the morning and try all the ways I know and finally I failed to perform this .... is it possible to display all the keys values previously stored in the player prefs ??? or can someone to provide me by a JavaScript to do this ???? thanks...

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• Advantages and disadvantages of libgdx [on hold]

  - by Paul

  I've been an android developer for a while and am thinking about getting into gaming. While looking for a game dev framework, I thought libgdx provides very friendly documentation and functionality. So I would like to use it if there is no big obstacle. But when I tried to see how many developers employ this library, I could find not that many. Is there anything wrong with this library? In other words, I would like to know its advantages or disadvantages from any experienced developer. UPDATE: After reviewing its documentations and trying to build simple games with libgdx, I decided to go with it as its documentations are good enough and its community is very active. What I liked the most is that it provides a bunch of demo games that I can learn a lot from.

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• How to use Pixel Bender (pbj) in ActionScript3 on large Vectors to make fast calculations?

  - by Arthur Wulf White

  Remember my old question: 2d game view camera zoom, rotation & offset using 'Filter' / 'Shader' processing? I figured I could use a Pixel Bender Shader to do the computation for any large group of elements in a game to save on processing time. At least it's a theory worth checking. I also read this question: Pass large array to pixel shader Which I'm guessing is about accomplishing the same thing in a different language. I read this tutorial: http://unitzeroone.com/blog/2009/03/18/flash-10-massive-amounts-of-3d-particles-with-alchemy-source-included/ I am attempting to do some tests. Here is some of the code: private const SIZE : int = Math.pow(10, 5); private var testVectorNum : Vector.<Number>; private function testShader():void { shader.data.ab.value = [1.0, 8.0]; shader.data.src.input = testVectorNum; shader.data.src.width = SIZE/400; shader.data.src.height = 100; shaderJob = new ShaderJob(shader, testVectorNum, SIZE / 4, 1); var time : int = getTimer(), i : int = 0; shaderJob.start(true); trace("TEST1 : ", getTimer() - time); } The problem is that I keep getting a error saying: [Fault] exception, information=Error: Error #1000: The system is out of memory. Update: I managed to partially workaround the problem by converting the vector into bitmapData: (Using this technique I still get a speed boost of 3x using Pixel Bender) private function testShader():void { shader.data.ab.value = [1.0, 8.0]; var time : int = getTimer(), i : int = 0; testBitmapData.setVector(testBitmapData.rect, testVectorInt); shader.data.src.input = testBitmapData; shaderJob = new ShaderJob(shader, testBitmapData); shaderJob.start(true); testVectorInt = testBitmapData.getVector(testBitmapData.rect); trace("TEST1 : ", getTimer() - time); }

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• How do I efficiently code both the client and server at the same time?

  - by liamzebedee

  I'm coding my game using a client-server model. When playing on singleplayer, the game starts a local server, and interacts with it just like a remote server (multiplayer). I have done this to avoid coding separate singleplayer and multiplayer code. I have just started coding and have encountered a major problem. Currently I'm developing the game in Eclipse, having all the game classes organized into packages. Then, in my server code, I just use all the classes in the client packages. The problem is, these client classes have variables that are specific to rendering, which obviously wouldn't be performed on a server. Should I create modified versions of the client classes to use in the server? Or should I just modify the client classes with a boolean, to indicate if its the client/server using it. Are there any other options I have? I just had a thought about maybe using the server class as the core class, then extending it with rendering stuff?

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• Simultaneous AI in turn based games

  - by Eduard Strehlau

  I want to hack together a roguelike. Now I thought about entity and world representation and got to a quite big problem. If you want all the AI to act simultaneously you would normally(in cellular automa for examble) just copy the cell buffer and let all action of indiviual cells depend on the copy. Actions which are not valid anymore after some cell before the cell you are currently operating on changed the original enviourment(blocking the path) are just ignored or reapplied with the "current"(between turns) environment. After all cells have acted you copy the current map to the buffer again. Now for an environment with complex AI and big(datawise) entities the copying would take too long. So I thought you could put every action and entity makes into a que(make no changes to the environment) and execute the whole que after everyone took their move. Every interaction on this que are realy interacting entities, so if a entity tries to attack another entity it sends a message to it, the consequences of the attack would be visible next turn, either by just examining the entity or asking the entity for data. This would remove problems like what happens if an entity dies middle in the cue but got actions or is messaged later on(all messages would go to null, and the messages from the entity would either just be sent or deleted(haven't decided yet) But what would happen if a monster spawns a fireball which by itself tracks the player(in the same turn). Should I add the fireball to the enviourment beforehand, so make a change to the environment before executing the action list or just add the ball to the "need updated" list as a special case so it doesn't exist in the environment and still operates on it, spawing after evaluating the action list? Are there any solutions or papers on this subject which I can take a look at? EDIT: I don't need information on writing a roguelike I need information on turn based ai in respective to a complex enviourment.

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• How to move an UIView along a curved CGPath according to user dragging the view

  - by Felipe Cypriano

  I'm trying to build a interface that the user can move his finger around the screen an a list of images moves along a path. The idea is that the images center nevers leaves de path. Most of the things I found was about how to animate using CGPath and not about actually using the path as the track to a user movement. I need to objects to be tracked on the path even if the user isn't moving his fingers over the path. For example (image bellow), if the object is at the beginning of the path and the user touches anywhere on the screen and moves his fingers from left to right I need that the object moves from left to right but following the path, that is, going up as it goes to the right towards the path's end. This is the path I've draw, imagine that I'll have a view (any image) that the user can touch and drag it along the path, there's no need to move the finger exactly over the path. If the user move from left to right the image should move from left to right but going up if need following the path. This is how I'm creating the path: CGPoint endPointUp = CGPointMake(315, 124); CGPoint endPointDown = CGPointMake(0, 403); CGPoint controlPoint1 = CGPointMake(133, 187); CGPoint controlPoint2 = CGPointMake(174, 318); CGMutablePathRef path = CGPathCreateMutable(); CGPathMoveToPoint(path, NULL, endPointUp.x, endPointUp.y); CGPathAddCurveToPoint(path, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, endPointDown.x, endPointDown.y); Any idead how can I achieve this?

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• How to change speed without changing path travelled?

  - by Ben Williams

  I have a ball which is being thrown from one side of a 2D space to the other. The formula I am using for calculating the ball's position at any one point in time is: x = x0 + vx0*t y = y0 + vy0*t - 0.5*g*t*t where g is gravity, t is time, x0 is the initial x position, vx0 is the initial x velocity. What I would like to do is change the speed of this ball, without changing how far it travels. Let's say the ball starts in the lower left corner, moves upwards and rightwards in an arc, and finishes in the lower right corner, and this takes 5s. What I would like to be able to do is change this so it takes 10s or 20s, but the ball still follows the same curve and finishes in the same position. How can I achieve this? All I can think of is manipulating t but I don't think that's a good idea. I'm sure it's something simple, but my maths is pretty shaky.

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• Identify which CCSprite is touched in Cocos2d

  - by PeterK

  I am trying to learn Cocos2d and is experimenting with Ray Wenderlich tutorial whack-a-mole: www.raywenderlich.com/2560/how-to-create-a-mole-whacking-game-with-cocos2d-part-1 In this tutorial three CCSprite's are popping up and you should click on them... However, i am trying to identify which mole, rat in my case, is popping up and place a CCSprite above that. Initially this looked like an easy task but i am failing. I am trying to NSLog LEFT HIT. i would guess the problem is in the If-statement and the last "227" height parameter. The left rat boundingBox = {{99.5, 146.5}, {165, 227}} (from NSLog). The key code is in the ccTouchBegan function: -(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event { CGPoint touchLocation = [self convertTouchToNodeSpace:touch]; for (CCSprite *rat in rats) { if (rat.userData == FALSE) continue; if (CGRectContainsPoint(rat.boundingBox, touchLocation)) { //left: rat boundingBox = {{99.5, 146.5}, {165, 227}} //mid: rat boundingBox = {{349.5, 146.5}, {165, 227}} //right: rat boundingBox = {{599.5, 146.5}, {165, 227}} //>>>>Here is where i try to get a hit<<<< if (CGRectContainsPoint(CGRectMake(99.5, 146.55, 165, 227), touchLocation)) { NSLog(@">>>>HIT LEFT<<<<<"); } I would really appreciate a few ideas how to get this to work.

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• PCF shadow shader math causing artifacts

  - by user2971069

  For a while now I used PCSS for my shadow technique of choice until I discovered a type of percentage closer filtering. This method creates really smooth shadows and with hopes of improving performance, with only a fraction of texture samples, I tried to implement PCF into my shader. This is the relevant code: float c0, c1, c2, c3; float f = blurFactor; float2 coord = ProjectedTexCoords; if (receiverDistance - tex2D(lightSampler, coord + float2(0, 0)).x > 0.0007) c0 = 1; if (receiverDistance - tex2D(lightSampler, coord + float2(f, 0)).x > 0.0007) c1 = 1; if (receiverDistance - tex2D(lightSampler, coord + float2(0, f)).x > 0.0007) c2 = 1; if (receiverDistance - tex2D(lightSampler, coord + float2(f, f)).x > 0.0007) c3 = 1; coord = (coord % f) / f; return 1 - (c0 * (1 - coord.x) * (1 - coord.y) + c1 * coord.x * (1 - coord.y) + c2 * (1 - coord.x) * coord.y + c3 * coord.x * coord.y); This is a very basic implementation. blurFactor is initialized with 1 / LightTextureSize. So the if statements fetch the occlusion values for the four adjacent texels. I now want to weight each value based on the actual position of the texture coordinate. If it's near the bottom-right pixel, that occlusion value should be preferred. The weighting itself is done with a simple bilinear interpolation function, however this function takes a 2d vector in the range [0..1] so I have to convert my texture coordinate to get the distance from my first pixel to the second one in range [0..1]. For that I used the mod operator to get it into [0..f] range and then divided by f. This code makes sense to me, and for specific blurFactors it works, producing really smooth one pixel wide shadows, but not for all blurFactors. Initially blurFactor is (1 / LightTextureSize) to sample the 4 adjacent texels. I now want to increase the blurFactor by factor x to get a smooth interpolation across maybe 4 or so pixels. But that is when weird artifacts show up. Here is an image: Using a 1x on blurFactor produces a good result, 0.5 is as expected not so smooth. 2x however doesn't work at all. I found that only a factor of 1/2^n produces an good result, every other factor produces artifacts. I'm pretty sure the error lies here: coord = (coord % f) / f; Maybe the modulo is not calculated correctly? I have no idea how to fix that. Is it even possible for pixel that are further than 1 pixel away?

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