Lighting models are specified with the Light Model function.
Light Model( argument, value,...,value )
Light models specify three attributes of lights.
• The global ambient light intensity
• Whether the viewpoint is local or is an infinite distance away
• Whether lighting calculations should be performed differently for the front and back faces of objects.
表 13.4 shows the three valid arguments for the Light Model function.
|
Argument |
Default Value |
Meaning |
|---|---|---|
|
LIGHT_MODEL_AMBIENT |
(0.2, 0.2, 0.2, 1) |
Ambient RGBA intensity of the entire scene |
|
LIGHT_MODEL_LOCAL_VIEWER |
0 (false) |
how specular reflection angles are computed |
|
LIGHT_MODEL_TWO_SIDE |
0 (false) |
nonzero values imply two-sided lighting |