What Is a Viewport?

Conceptually, a viewport is a 2-D rectangle into which a three dimensional scene is projected. (In Direct3D, the rectangle exists as coordinates within a DirectDraw 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:

• The screen-space viewport to which the rendering will be confined.
• The range of depth values on a render-target surface into which a scene will be rendered (usually 0.0 to 1.0).