Draw Region Services

The draw region can perform, at the direction of the renderer, two optional services: it can clear the rendering target (e.g., a window) and it can lock the target's DDSurface draw context type in a Windows environment.

These two services are described by the following enumeration:

typedef enum TQ3XDrawRegionServicesMasks {
    kQ3XDrawRegionServicesNoneFlag                  = 0L,
    kQ3XDrawRegionServicesClearFlag                 = 1 << 0,
    kQ3XDrawRegionServicesDontLockDDSurfaceFlag     = 1 << 1
} TQ3XDrawRegionServicesMasks;
typedef unsigned long TQ3XDrawRegionServices;


The renderer controls which of these services are used by passing a value in Q3XDrawRegion_Start (link) or Q3XDrawRegion_StartAccessToImageBuffer (link) .

If a draw context must be cleared before each frame, either the draw region or the renderer must be directed to do the clearing. The same applies to locking the DDSurface when using that particular Windows draw context type.

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© 1997 Apple Computer, Inc.

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