game-physics

I'm trying to use a quadtree for 2D collision detection, but I'm a little stumped on how to implement it. First of all, I'd have a quadtree which contains four subtrees (one representing each quadrant), as well as a collection of objects which don't fit into a single subtree. When checking an object for collisions in the tree, I would do something like this (thanks to QuadTree for 2D collision detection ): Check the object for collisions with any objects in the current node. For any subtree whose space overlaps the object, recurse. To find all collisions within a quadtree tree: Check each

I'm attempting to work out simple controls for an application using pygame in Python. I have got the basics working, but I'm hitting a weird wall: I am using the arrow keys to control my character. If I hold down one arrow key, then hold down another arrow key (to move diagonally), the character moves as expected. However, if I release the second key that I pressed (while still holding down the first key), the character stops moving, even though I am still holding down that first key. Here is my simple movement code: for event in pygame.event.get(): if event.type == QUIT: pygame.quit() sys

I wonder if there is a tool that could be used for easy generation of complex physics bodies in SpriteKit. I would like to have a volume based physical bodies with polygon-type shapes. SpriteKit allows to create such bodies with that method: + (SKPhysicsBody *)bodyWithPolygonFromPath:(CGPathRef)path Unfortunately it's time consuming task to generate such paths manually, and it could be problematic when testing. There is a SpriteHelper application that allows you to define body shape within easy-to-use visual editor, but this app can't export paths that could be used here. It was made for

I have pitch, roll, and yaw angles. How would I convert these to a directional vector? It'd be especially cool if you can show me a quaternion and/or matrix representation of this! Unfortunately there are different conventions on how to define these things (and roll, pitch, yaw are not quite the same as Euler angles), so you'll have to be careful. If we define pitch=0 as horizontal (z=0) and yaw as counter-clockwise from the x axis, then the direction vector will be x = cos(yaw)*cos(pitch) y = sin(yaw)*cos(pitch) z = sin(pitch) Note that I haven't used roll; this is direction unit vector, it

I am building an iOS game aimed for the new iOS 7 and Sprite Kit, using emitter nodes and physics to enhance gameplay. While developing the app, I ran into a serious problem: you create your scenes, nodes, effects, but when you are done and need to return to the main screen, how do you free up all the memory allocated by these resources? Ideally ARC should free up everything and the application should get back to the memory consumption level it had before creating the scene, but this is not what happens. I've added the following code, as the dealloc method of the view, which draws the scene

I am working on some shaders, and I need to transform normals. I read in few tutorials the way you transform normals is you multiply them with the transpose of the inverse of the modelview matrix . But I can't find explanation of why is that so, and what is the logic behind that? Invalid Take a look at this tutorial: https://paroj.github.io/gltut/Illumination/Tut09%20Normal%20Transformation.html You can imagine that when the surface of a sphere stretches (so the sphere is scaled along one axis or something similar) the normals of that surface will all 'bend' towards each other. It turns out