3D Graphics Programming with QuickDraw 3D 1.5.4

Rendering With Antialiasing

A drawing engine may support an antialiasing mode that determines the kind of antialiasing applied to a drawing context. ( Antialiasing is the smoothing of jagged edges on a displayed shape by modifying the transparencies of individual pixels along the shape's edge.)

The antialiasing mode state variable is optional; it must be supported only when a drawing engine supports the kQAOptional_Antialias feature.

You specify an engine's antialiasing mode by assigning a value to its kQATag_Antialias state variable. QuickDraw 3D RAVE provides these constants for antialiasing modes:



 
#define kQAAntiAlias_Off                            0

#define kQAAntiAlias_Fast                           1

#define kQAAntiAlias_Mid                            2

#define kQAAntiAlias_Best                           3

The interpretation of these values is specific to each drawing engine. For example, a drawing engine might be able to support antialiased line drawing with no performance penalty but that same engine might incur a 50 percent slowdown when drawing antialiased triangles. Accordingly, this engine might interpret the kQAAntiAlias_Fast antialiasing mode as rendering antialiased lines only, and it might interpret the kQAAntiAlias_Mid mode as rendering both antialiased lines and triangles.

QuickDraw 3D RAVE interprets antialiasing modes independently of the transparency blending modes, unlike some other rendering technologies. For instance, with OpenGL you must select specific blending modes when antialiasing is enabled.