| Platform SDK: DirectX |
Before rendering objects in a scene, clear the viewport on the render-target surface (or a subset of the viewport). Clearing the viewport causes the system to set the desired portion of the render-target surface and any attached depth or stencil buffers to a desired state. This resets the areas of the surface that will be rendered again and resets the corresponding areas of the depth and stencil buffers, if any are in use. Clearing a render-target surface can set the desired region to a default color or texture. For depth and stencil buffers, this can set a depth or stencil value.
The IDirect3DDevice7 interface offers the IDirect3DDevice7::Clear method to clear the viewport. For more information about using these methods, see Clearing a Viewport in the Viewports and Clipping section.
The Direct3DDevice7 Visual Basic class offers the Direct3DDevice7.Clear method to clear the viewport. For more information about using these methods, see Clearing a Viewport in the Viewports and Clipping section.
Optimization Note Applications that render scenes covering the entire area of the render-target surface can improve performance by clearing the attached depth and stencil buffer surfaces (if any) instead of the render target. In this case, clearing the depth buffer causes Direct3D to rewrite the render target on the next rendered frame, making an explicit clear operation on the render target redundant. However, if your application renders only to a portion of the render-target surface, explicit clear operations are required.