Hi, There is disagreement about the meaning of the CLIPSPAN _n parameter in CVS.
The drivers I have looked at and drivers/dri/common/spantmp.h treat _n as the number of pixels in the span after clipping. depthtmp.h and stenciltmp.h treat _n as the end+1 x coordinate of the span. This inconsistency leads to artifacts when software fallbacks are hit while clipping is used, especially with partially obscured clients. The attached patch should fix these artifacts by changing depthtmp.h and stenciltmp.h appropriately. cu, Nicolai
Index: drivers/dri/common/depthtmp.h
===================================================================
RCS file: /cvs/mesa/Mesa/src/mesa/drivers/dri/common/depthtmp.h,v
retrieving revision 1.5
diff -u -p -b -r1.5 depthtmp.h
--- drivers/dri/common/depthtmp.h 8 Oct 2004 22:21:09 -0000 1.5
+++ drivers/dri/common/depthtmp.h 15 Oct 2004 19:48:14 -0000
@@ -45,15 +45,15 @@ static void TAG(WriteDepthSpan)( GLconte
GLint i = 0;
CLIPSPAN( x, y, n, x1, n1, i );
- if ( DBG ) fprintf( stderr, "WriteDepthSpan %d..%d (x1 %d)\n",
- (int)i, (int)n1, (int)x1 );
+ if ( DBG ) fprintf( stderr, "WriteDepthSpan %d..%d (x1 %d) (mask %p)\n",
+ (int)i, (int)n1, (int)x1, mask );
if ( mask ) {
- for ( ; i < n1 ; i++, x1++ ) {
+ for ( ; n1>0 ; i++, x1++, n1-- ) {
if ( mask[i] ) WRITE_DEPTH( x1, y, depth[i] );
}
} else {
- for ( ; i < n1 ; i++, x1++ ) {
+ for ( ; n1>0 ; i++, x1++, n1-- ) {
WRITE_DEPTH( x1, y, depth[i] );
}
}
@@ -87,11 +87,11 @@ static void TAG(WriteMonoDepthSpan)( GLc
__FUNCTION__, (int)i, (int)n1, (int)x1, (GLuint)depth );
if ( mask ) {
- for ( ; i < n1 ; i++, x1++ ) {
+ for ( ; n1>0 ; i++, x1++, n1-- ) {
if ( mask[i] ) WRITE_DEPTH( x1, y, depth );
}
} else {
- for ( ; i < n1 ; i++, x1++ ) {
+ for ( ; n1>0 ; x1++, n1-- ) {
WRITE_DEPTH( x1, y, depth );
}
}
@@ -162,8 +162,9 @@ static void TAG(ReadDepthSpan)( GLcontex
{
GLint i = 0;
CLIPSPAN( x, y, n, x1, n1, i );
- for ( ; i < n1 ; i++ )
- READ_DEPTH( depth[i], (x1+i), y );
+ for ( ; n1>0 ; i++, n1-- ) {
+ READ_DEPTH( depth[i], x+i, y );
+ }
}
HW_ENDCLIPLOOP();
#endif
Index: drivers/dri/common/stenciltmp.h
===================================================================
RCS file: /cvs/mesa/Mesa/src/mesa/drivers/dri/common/stenciltmp.h,v
retrieving revision 1.2
diff -u -p -b -r1.2 stenciltmp.h
--- drivers/dri/common/stenciltmp.h 6 Aug 2003 18:12:22 -0000 1.2
+++ drivers/dri/common/stenciltmp.h 15 Oct 2004 19:48:15 -0000
@@ -41,13 +41,13 @@ static void TAG(WriteStencilSpan)( GLcon
if (mask)
{
- for (;i<n1;i++,x1++)
+ for (;n1>0;i++,x1++,n1--)
if (mask[i])
WRITE_STENCIL( x1, y, stencil[i] );
}
else
{
- for (;i<n1;i++,x1++)
+ for (;n1>0;i++,x1++,n1--)
WRITE_STENCIL( x1, y, stencil[i] );
}
}
@@ -107,8 +107,8 @@ static void TAG(ReadStencilSpan)( GLcont
{
GLint i = 0;
CLIPSPAN(x,y,n,x1,n1,i);
- for (;i<n1;i++)
- READ_STENCIL( stencil[i], (x1+i), y );
+ for (;n1>0;i++,n1--)
+ READ_STENCIL( stencil[i], (x+i), y );
}
HW_ENDCLIPLOOP();
}
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