Surface-Based Shaders

Several of the base classes of shaders apply shading effects to the surfaces of geometric objects.

• Surface shaders are applied when calculating the appearance of a surface. A geometric object (or group of geometric objects) can be associated with a surface shader, which is called to evaluate the shading effect for each face, vertex, or pixel of the object. QuickDraw 3D currently defines one subclass of surface shaders:
• Texture shaders apply shading to an object using a texture. See "Textures" for more information on textures and texture shaders.
• Illumination shaders determine the effects of the view's group of lights on the objects in a model. QuickDraw 3D currently defines three subclasses of illumination shaders. See "Illumination Models" for more information on these illumination models.
• The Lambert illumination shader implements a Lambert illumination model.
• The Phong illumination shader implements a Phong illumination model.
• The null illumination shader draws objects using only the diffuse colors of those objects, ignoring the view's group of lights.