Can I raytrace with OpenGL?
OpenGL contains no direct support for raytracing. You might want to use raytracing to produce realistic shadows and reflections. However, you can simulate in many ways these effects in OpenGL without raytracing. See the section on shadows or the section on texture mapping for some algorithms. You can use OpenGL as part of the ray intersection test. For example, a scene can be rendered with a unique color assigned to each primitive in the scene. This color can be read back to determine the primitive intersected by a ray at a given pixel. If the exact geometry is used in this algorithm, some aliasing may result. To reduce these aliasing artifacts, you can render bounding volumes instead. Also, by changing the viewpoint and view direction, you can use this algorithm for intersection testing of secondary rays. A ray tracing application might also use OpenGL for displaying the final image. In this case, the application is responsible for computing the color value of each pixel. The pixels t
