3D Graphics Programming with QuickDraw 3D 1.5.4

Drawing in a Draw Context

QuickDraw 3D RAVE allows you to draw five kinds of objects in a draw context: points, lines, triangles, triangle meshes, and bitmaps. You draw by calling a function to draw the desired type of object. For instance, to draw a single point, you can call the QADrawPoint function, as follows:



 
QADrawPoint(myDrawContext, myPoint);

Here, the myPoint parameter specifies the point to draw. All objects that a drawing engine can draw (except for bitmaps) are defined by points or vertices. QuickDraw 3D RAVE supports two different types of vertices: Gouraud vertices and texture vertices. You use Gouraud vertices for drawing Gouraud-shaded triangles, and also for drawing points and lines. A Gouraud vertex is defined by the TQAVGouraud data structure, which specifies the position, depth, color, and transparency information.

You use texture vertices to define triangles to which a texture is to be mapped. A texture vertex is defined by the TQAVTexture data structure, which specifies the position, depth, transparency, and texture mapping information.

QuickDraw 3D RAVE does not currently support clipping to a draw context. All triangles and other objects drawn to a draw context must lie entirely within the draw context.