If color of objects was wrong from which it should be, what kind of error would happen? I had checked all the input of lighting and material of my program, they didn’t go wrong. And the program ran and draw objects well except the color…please tell me what kind of error would be possible, eg. function sequence
Materials have default properties so if you don’t set them you can have issues with defaults you’re not expecting.
In addition surface normals of unit length must be specified in the correct orientation for correct results too (you can normalize in hardware at a performance penalty too).