|Microsoft DirectX 9.0|
Conceptually, a viewport is a two-dimensional (2-D) rectangle into which a three-dimensional (3-D) scene is projected. In Microsoft?Direct3D? the rectangle exists as coordinates within a Direct3D surface that the system uses as a rendering target. The projection transformation converts vertices into the coordinate system used for the viewport.
You use a viewport in Direct3D to specify the following features in your application.
This section discusses clipping, the last stage of the geometry pipeline. The discussion is organized into the following topics.
Direct3D implements clipping by way of a set of viewport parameters set in the device.