3D Graphics Programming with QuickDraw 3D 1.5.4

Z Perspective Selectors

A drawing engine may support a z perspective control that determines whether the z or the invW field of a vertex (of type TQAVGouraud or TQAVTexture ) is to be used for hidden surface removal. You specify an engine's z perspective control by assigning a value to its kQATag_PerspectiveZ state variable. The default value of this variable for a drawing engine that supports z perspective is kQAPerspectiveZ_Off .



 
#define kQAPerspectiveZ_Off                         0

#define kQAPerspectiveZ_On                          1

Constant descriptions

kQAPerspectiveZ_Off: The drawing engine performs hidden surface removal using z values, as is standard.
kQAPerspectiveZ_On: The drawing engine performs hidden surface removal using invW values, which results in perspective-correct hidden surface removal.