On Jun 10, Jorge Valencia wrote:
> Is it possible to have a single call to render multiple polygons (lines) at
> the same time instead of calling the XRenderCompositeDoublePoly() function
> for each of the polygons? (something analogous to XDrawSegments() for
> XSegments).
> This would avoid the performance penalty of the function call overhead which
> is considerable when thousand of polygons are redrawn per iteration.
More important than any possible performance improvement:
It's necessary to process multiple polygons simultaneously in order to
correctly render shapes that can't be specified by a single polygon,
(ie. closed line paths including "donuts").
For that reason, I was just about to code up
XRenderCompositeDoublePolys. But I think I'll go to bed instead. I'll
probably get to it early tomorrow morning.
All it needs is a new interface -- the internal tessellation code
should work just fine as is.
It would also be desirable to have the winding parameter actually
work, (eg. cause the tessellation to use the non-zero winding rule
rather than the even-odd rule). The attached patch seems to do the
trick for that.
-Carl
Index: Poly.c
===================================================================
RCS file: /mirrors/xfree86/xc/lib/Xrender/Poly.c,v
retrieving revision 1.7
diff -u -r1.7 Poly.c
--- Poly.c 4 Jun 2002 23:22:36 -0000 1.7
+++ Poly.c 6 Jun 2002 13:08:02 -0000
@@ -93,6 +93,7 @@
Edge *active;
Edge *e, *en, *next;
XFixed y, next_y, intersect;
+ int in_out;
qsort (edges, nedges, sizeof (Edge), CompareEdge);
@@ -189,8 +190,24 @@
next_y = edges[inactive].edge.p1.y;
/* walk the list generating trapezoids */
- for (e = active; e && (en = e->next); e = en->next)
+ in_out = 0;
+ for (e = active; e && (en = e->next); e = e->next)
{
+ if (winding) {
+ if (e->clockWise) {
+ in_out++;
+ } else {
+ in_out--;
+ }
+ if (in_out == 0) {
+ continue;
+ }
+ } else {
+ in_out++;
+ if (in_out % 2 == 0) {
+ continue;
+ }
+ }
traps->top = y;
traps->bottom = next_y;
traps->left = e->edge;
--
Carl Worth
USC Information Sciences Institute [EMAIL PROTECTED]
3811 N. Fairfax Dr. #200, Arlington VA 22203 703-812-3725
