From 17542086174ed1c2ea47f3b9b5917ce478442819 Mon Sep 17 00:00:00 2001 From: Roland Scheidegger Date: Tue, 1 Sep 2015 16:29:17 -0600 Subject: [PATCH] gallium/util: fix returning empty box for rectangle intersection These functions deal with inclusive coordinates, hence a 0/0/0/0 rect returned when there's no intersection doesn't actually represent an empty rectangle. Hence return 0/-1/0/-1 instead. This fixes some problems in llvmpipe with empty scissor rects (which up to now didn't really matter because while the intersect test returned the wrong result all pixels were scissored away later anyway). --- src/gallium/auxiliary/util/u_rect.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/gallium/auxiliary/util/u_rect.h b/src/gallium/auxiliary/util/u_rect.h index dea1e1e..221d918 100644 --- a/src/gallium/auxiliary/util/u_rect.h +++ b/src/gallium/auxiliary/util/u_rect.h @@ -87,7 +87,12 @@ u_rect_possible_intersection(const struct u_rect *a, u_rect_find_intersection(a,b); } else { - b->x0 = b->x1 = b->y0 = b->y1 = 0; + /* + * Note the u_rect_xx tests deal with inclusive coordinates + * hence all-zero would not be an empty box. + */ + b->x0 = b->y0 = 0; + b->x1 = b->y1 = -1; } } -- 2.7.4