GXSetCopyClamp

C Specification

#include <revolution/gx.h>

void GXSetCopyClamp( GXFBClamp clamp );

Arguments

clamp

clamp mode The OR bit of GXFBClamp. Accepted values are:

Name	where the clamp occurs
`GX_CLAMP_NONE`	no clamping
`GX_CLAMP_TOP`	the uppermost line
`GX_CLAMP_BOTTOM`	the lowest line
`GX_CLAMP_TOP \| GX_CLAMP_BOTTOM`	both the uppermost and the lowest

Return Values

None

Description

This function sets the vertical clamping mode to use during the Embedded Frame Buffer (EFB) to External Frame Buffer (XFB) or texture copy.

If you use vertical filter (see GXSetCopyFilter), the GP looks up contiguous three lines at the same time for filtering during copy. This means some data can come out of the region specified by GXSetDispCopySrc or from GXSetTexCopySrc when it copies the top-most line or bottom-most line. Vertical clamping avoids pulling samples from such out-of-regions. For example, usually the GP attempts to look up three lines {top-1, top, top+1} for copying the first line. But if clamping is working, the look-up becomes {top, top, top+1} and prevents the GP from looking up the line (top-1) which is out of region.

Revision History

2006/03/01 Initial version