I put a QUAD in the space and textured a image onto it, so that it looks like a background. I also put a cube on the space and disable the depth test, the code is like:
put a Quad
mapping texture
disable depth test
put a cube
enable texture
…
now I want to give some light effect on it so that I can simulate daytime and nighttime.
question is:
what kind of light I should put on?
how to light it?
how can I set a nomal to object?
once I set a nomal to object, how opengl keep it?