checkers being drawn as many glRects is slow when zoomed in, use

glPolygonStipple draw checkers.

1 files changed, 18 insertions, 49 deletions

diff --git a/source/blender/src/drawimage.c b/source/blender/src/drawimage.c
index 789e33964fc..85be4298922 100644
--- a/source/blender/src/drawimage.c
+++ b/source/blender/src/drawimage.c
@@ -1704,61 +1704,30 @@ static void imagespace_grid(SpaceImage *sima)
 	
 }
 
-#define ALPHA_CHECKSIZE 30
 static void sima_draw_alpha_backdrop(SpaceImage *sima, float x1, float y1, float xsize, float ysize)
 {
-	float tile= ALPHA_CHECKSIZE/2;
-	float x, y, maxx, maxy;
-	float xstart, ystart;
-	int checker_type = 0;
+	GLubyte checker_stipple[32*32/8] =
+	{
+		255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0, \
+		255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0, \
+		255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0, \
+		255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0, \
+		0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255, \
+		0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255, \
+		0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255, \
+		0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255, \
+	};
+	
 	glColor3ub(100, 100, 100);
 	glRectf(x1, y1, x1 + sima->zoom*xsize, y1 + sima->zoom*ysize);
 	glColor3ub(160, 160, 160);
 	
-	maxx= x1+sima->zoom*xsize;
-	maxy= y1+sima->zoom*ysize;
-	
-	xstart = fmod((float)sima->xof*sima->zoom, ALPHA_CHECKSIZE);
-	ystart = fmod((float)sima->yof*sima->zoom, ALPHA_CHECKSIZE);
-	
-	if (xstart>0) xstart-=ALPHA_CHECKSIZE;
-	if (ystart>0) ystart-=ALPHA_CHECKSIZE;
-	
-	ystart = ystart/sima->zoom;
-	xstart = xstart/sima->zoom;
-	
-	while (checker_type != 2) {
-		
-		/* there are only 2 checker_type's - 0 or 1 , offset the quads to make check's second time round */
-		if (checker_type==1) {
-			xstart -= ALPHA_CHECKSIZE*0.5/sima->zoom;
-			ystart -= ALPHA_CHECKSIZE*0.5/sima->zoom;
-		}
-		
-		for(x=xstart; x<xsize; x+=ALPHA_CHECKSIZE/sima->zoom) {
-			float fx= x1 + sima->zoom*x;
-			if (fx+tile < x1)
-				continue;
-			
-			for(y=ystart; y<ysize; y+=ALPHA_CHECKSIZE/sima->zoom) {
-				float fy= y1 + sima->zoom*y;
-				float tilex= tile, tiley= tile;
-				
-				/* skip min values */
-				if (fy+tile<y1)
-					continue;
-				
-				/* clip max values */
-				if(fx+tile > maxx)
-					tilex= maxx-fx;
-				if(fy+tile > maxy)
-					tiley= maxy-fy;
-				
-				glRectf(MAX2(fx, x1), MAX2(fy, y1), fx + tilex, fy + tiley);
-			}
-		}
-		checker_type++;
-	}
+	glEnable(GL_POLYGON_STIPPLE);
+	glPolygonStipple(checker_stipple);
+	glRectf(x1, y1, x1 + sima->zoom*xsize, y1 + sima->zoom*ysize);
+	glEnd();
+	glDisable(GL_POLYGON_STIPPLE);
+	return;
 }
 
 static void sima_draw_alpha_pixels(float x1, float y1, int rectx, int recty, unsigned int *recti)