From 2a121e8e2289d2ca136f511c5a6ef049f9c99ec4 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Fri, 29 Feb 2008 11:37:12 -0700 Subject: [PATCH] gallium: tweak coords for wide lines --- src/gallium/auxiliary/draw/draw_wide_line.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/src/gallium/auxiliary/draw/draw_wide_line.c b/src/gallium/auxiliary/draw/draw_wide_line.c index 946a983f008..9a168ce8bdc 100644 --- a/src/gallium/auxiliary/draw/draw_wide_line.c +++ b/src/gallium/auxiliary/draw/draw_wide_line.c @@ -86,7 +86,10 @@ static void wideline_line( struct draw_stage *stage, const float dx = FABSF(pos0[0] - pos2[0]); const float dy = FABSF(pos0[1] - pos2[1]); - + + /* small tweak to meet GL specification */ + const float bias = 0.125f; + /* * Draw wide line as a quad (two tris) by "stretching" the line along * X or Y. @@ -95,10 +98,10 @@ static void wideline_line( struct draw_stage *stage, if (dx > dy) { /* x-major line */ - pos0[1] = pos0[1] - half_width - 0.25f; - pos1[1] = pos1[1] + half_width - 0.25f; - pos2[1] = pos2[1] - half_width - 0.25f; - pos3[1] = pos3[1] + half_width - 0.25f; + pos0[1] = pos0[1] - half_width - bias; + pos1[1] = pos1[1] + half_width - bias; + pos2[1] = pos2[1] - half_width - bias; + pos3[1] = pos3[1] + half_width - bias; if (pos0[0] < pos2[0]) { /* left to right line */ pos0[0] -= 0.5f; @@ -116,10 +119,10 @@ static void wideline_line( struct draw_stage *stage, } else { /* y-major line */ - pos0[0] = pos0[0] - half_width + 0.25f; - pos1[0] = pos1[0] + half_width + 0.25f; - pos2[0] = pos2[0] - half_width + 0.25f; - pos3[0] = pos3[0] + half_width + 0.25f; + pos0[0] = pos0[0] - half_width + bias; + pos1[0] = pos1[0] + half_width + bias; + pos2[0] = pos2[0] - half_width + bias; + pos3[0] = pos3[0] + half_width + bias; if (pos0[1] < pos2[1]) { /* top to bottom line */ pos0[1] -= 0.5f;