Archived

This topic is now archived and is closed to further replies.

Krak

OpenGL Collision Detection in OpenGL

Recommended Posts

Krak    116
1.) How is it done? 2.) Is it hard to learn how to do? 3.) Could you link me to some good tutorials on it?

Share this post


Link to post
Share on other sites
Guest Anonymous Poster   
Guest Anonymous Poster
Open <i>Graphics Library</i>. Graphics. Not Game.

Your game should need no knowledge of its graphics rendering to perform collision detection. You perform collision detection checks directly on your game data.

If you can''t grap that concept, go think about it in more detail. Then start googling for various geometry intersection testing methods (circle/circle or sphere/sphere is about as easy as it gets).

Share this post


Link to post
Share on other sites
Krak    116
quote:
Original post by Anonymous Poster
Open Graphics Library. Graphics. Not Game.

Your game should need no knowledge of its graphics rendering to perform collision detection. You perform collision detection checks directly on your game data.

If you can''t grap that concept, go think about it in more detail. Then start googling for various geometry intersection testing methods (circle/circle or sphere/sphere is about as easy as it gets).


I''m only talking about detecting if two 2D rectangles collide. Any particular functions or methods you''d use?

Share this post


Link to post
Share on other sites
Guest Anonymous Poster   
Guest Anonymous Poster
there are no functions to do that in opengl
as he said, opengl > gl = graphic library
it simply put your graphics on screen

you have to perform your collision yourself(google!!!!)
but for two triangle, you should have their position and size store somewhere and test if they collide

here a simple example in c

typedef struct{
int pos[2];
int size[2];
}rect_t;

bool collide(rect_t r1,rect_t r2)
{
// here you test the position of the rectangles to check collision
}

Share this post


Link to post
Share on other sites
OrangyTang    1298
For 2d rects, you can either have them axis-aligned, or orientated (rotated). Axis aligned is easy - you just need to see if the rectangles overlap on both the x and y axies.

First a class for the rects - held with position (x,y) and size (width,height). x+(width/2) is one edge, x-(width/2) is the other etc.

1. Find separation on x-axis. This is rect1.position - rect2.position. This may be negative, so make it posative if it is.

2. Find the total size of both controls in the x-axis. This is rect1.width/2 + rect2.width/2.

3. If separation < total size, then they overlap on the x-axis.

4. Repeat using the y coords and the height. If both test pass, the rectangles intersect

If you want rotated boxes, you''re on your own. Try googling for OBB (orientated bounding box).

Share this post


Link to post
Share on other sites

  • Similar Content

    • By povilaslt2
      Hello. I'm Programmer who is in search of 2D game project who preferably uses OpenGL and C++. You can see my projects in GitHub. Project genre doesn't matter (except MMO's :D).
    • By ZeldaFan555
      Hello, My name is Matt. I am a programmer. I mostly use Java, but can use C++ and various other languages. I'm looking for someone to partner up with for random projects, preferably using OpenGL, though I'd be open to just about anything. If you're interested you can contact me on Skype or on here, thank you!
      Skype: Mangodoor408
    • By tyhender
      Hello, my name is Mark. I'm hobby programmer. 
      So recently,I thought that it's good idea to find people to create a full 3D engine. I'm looking for people experienced in scripting 3D shaders and implementing physics into engine(game)(we are going to use the React physics engine). 
      And,ye,no money =D I'm just looking for hobbyists that will be proud of their work. If engine(or game) will have financial succes,well,then maybe =D
      Sorry for late replies.
      I mostly give more information when people PM me,but this post is REALLY short,even for me =D
      So here's few more points:
      Engine will use openGL and SDL for graphics. It will use React3D physics library for physics simulation. Engine(most probably,atleast for the first part) won't have graphical fron-end,it will be a framework . I think final engine should be enough to set up an FPS in a couple of minutes. A bit about my self:
      I've been programming for 7 years total. I learned very slowly it as "secondary interesting thing" for like 3 years, but then began to script more seriously.  My primary language is C++,which we are going to use for the engine. Yes,I did 3D graphics with physics simulation before. No, my portfolio isn't very impressive. I'm working on that No,I wasn't employed officially. If anybody need to know more PM me. 
       
    • By Zaphyk
      I am developing my engine using the OpenGL 3.3 compatibility profile. It runs as expected on my NVIDIA card and on my Intel Card however when I tried it on an AMD setup it ran 3 times worse than on the other setups. Could this be a AMD driver thing or is this probably a problem with my OGL code? Could a different code standard create such bad performance?
    • By Kjell Andersson
      I'm trying to get some legacy OpenGL code to run with a shader pipeline,
      The legacy code uses glVertexPointer(), glColorPointer(), glNormalPointer() and glTexCoordPointer() to supply the vertex information.
      I know that it should be using setVertexAttribPointer() etc to clearly define the layout but that is not an option right now since the legacy code can't be modified to that extent.
      I've got a version 330 vertex shader to somewhat work:
      #version 330 uniform mat4 osg_ModelViewProjectionMatrix; uniform mat4 osg_ModelViewMatrix; layout(location = 0) in vec4 Vertex; layout(location = 2) in vec4 Normal; // Velocity layout(location = 3) in vec3 TexCoord; // TODO: is this the right layout location? out VertexData { vec4 color; vec3 velocity; float size; } VertexOut; void main(void) { vec4 p0 = Vertex; vec4 p1 = Vertex + vec4(Normal.x, Normal.y, Normal.z, 0.0f); vec3 velocity = (osg_ModelViewProjectionMatrix * p1 - osg_ModelViewProjectionMatrix * p0).xyz; VertexOut.velocity = velocity; VertexOut.size = TexCoord.y; gl_Position = osg_ModelViewMatrix * Vertex; } What works is the Vertex and Normal information that the legacy C++ OpenGL code seem to provide in layout location 0 and 2. This is fine.
      What I'm not getting to work is the TexCoord information that is supplied by a glTexCoordPointer() call in C++.
      Question:
      What layout location is the old standard pipeline using for glTexCoordPointer()? Or is this undefined?
       
      Side note: I'm trying to get an OpenSceneGraph 3.4.0 particle system to use custom vertex, geometry and fragment shaders for rendering the particles.
  • Popular Now