View Full Version : How to simulate light?

04-03-2002, 09:57 PM
Hi all!
I want to implement a drive simulation using OpenGL. In the application , headlight, streetlight and time changing are all needed. How to implement these effects at the same time just like in game "Need For Speed".
Can anyone give me some ideas?
Thank u very much!
Sorry for my poor English.


04-03-2002, 11:04 PM
Why do you want to 'simulate' the light ? With OpenGL you can get a true, dynamic light ! You should look for some tutorials, for example have a look at http://nehe.gamedev.net
If you're new to opengl, it might be a good idea to get the 'opengl superbible' book.
I don't know need for speed well enough to see what you're talking about, but all you need to achieve reasonnable lighting in a game is available in openGL: colored lights, material properties, lights at infinity (like the sun), spotlights, and up to 8 lights lighting the same triangle in only one pass. All that you hardware can do is available through opengl.


04-04-2002, 02:44 AM
Thanks Morglum.

But there are some problems when using OpenGL true lights.
1.When using true spotlights, if two vertex of a triangle are out of frustum, the triangle will not be lighted.
2.when more than 8 lights are needed in a scene(such as in a channel), OpenGL can't satisfy.

I implement time changing using OpenGL infinity light as the sun. It works well.
And I implement a headlight by add a dynamic spotlight in scene. Because of problem 1 ,the headlight doesn't work well. Some triangles in scene can't be lighted.

I know multi-texture and light map can be used to simulate light and vertex coloring can be used to simulate light also. But I don't know how to use these methods to simulate a headlight and how to let them work with OpenGL true lights(like the sun) at the same time.