GXSetCopyClamp

Syntax

#include <revolution/gx.h>

void GXSetCopyClamp( GXFBClamp clamp );

Arguments

clamp Clamp mode. The bit OR 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 a vertical filter (see the GXSetCopyFilter function), the GP looks up three contiguous lines at the same time for filtering during copy. This means some data can come from outside of the region specified in the GXSetDispCopySrc or GXSetTexCopySrc function 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.

See Also

GXCopyDisp, GXCopyTex

Revision History

2006/03/01 Initial version.


CONFIDENTIAL