[Bf-blender-cvs] [91f04b8] blender2.8: early out for ortho grid drawing

[Mike Erwin]

Commit: 91f04b82a50603e12722e5a00185a9bb75fa1dde
Author: Mike Erwin
Date:   Sat Aug 13 22:33:49 2016 -0400
Branches: blender2.8
https://developer.blender.org/rB91f04b82a50603e12722e5a00185a9bb75fa1dde

early out for ortho grid drawing

Helps most when real-world units are used.

Previous code started at the smallest visible unit (e.g. Inches) then
followed to Feet, Yards, Chains, Furlongs, Miles. Always to the largest
unit of the set, even though most would be way off screen.

New code knows whether it skipped any grid lines for the next unit to
fill in, can stop once all lines are on screen.

===================================================================

M	source/blender/editors/space_view3d/view3d_draw.c

===================================================================

diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index ab4ba1b..7496aa0 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -267,7 +267,7 @@ static int gridline_count(ARegion *ar, double x0, double y0, double dx)
 	return total_ct;
 }
 
-static void drawgrid_draw(ARegion *ar, double x0, double y0, double dx, int skip_mod, unsigned pos, unsigned col, GLubyte col_value[3])
+static bool drawgrid_draw(ARegion *ar, double x0, double y0, double dx, int skip_mod, unsigned pos, unsigned col, GLubyte col_value[3])
 {
 	/* skip every skip_mod lines relative to each axis; they will be overlaid by another drawgrid_draw
 	 * always skip exact x0 & y0 axes; they will be drawn later in color
@@ -285,6 +285,7 @@ static void drawgrid_draw(ARegion *ar, double x0, double y0, double dx, int skip
 
 	int first, ct;
 	int x_ct = 0, y_ct = 0; /* count of lines actually drawn */
+	int lines_skipped_for_next_unit = 0;
 
 	/* draw vertical lines */
 	gridline_range(x0, dx, x_max, &first, &ct);
@@ -293,6 +294,7 @@ static void drawgrid_draw(ARegion *ar, double x0, double y0, double dx, int skip
 		if (i == 0)
 			continue;
 		else if (skip_mod && (i % skip_mod) == 0) {
+			++lines_skipped_for_next_unit;
 			continue;
 		}
 
@@ -312,6 +314,7 @@ static void drawgrid_draw(ARegion *ar, double x0, double y0, double dx, int skip
 		if (i == 0)
 			continue;
 		else if (skip_mod && (i % skip_mod) == 0) {
+			++lines_skipped_for_next_unit;
 			continue;
 		}
 
@@ -326,8 +329,10 @@ static void drawgrid_draw(ARegion *ar, double x0, double y0, double dx, int skip
 
 #if DEBUG_GRID
 	int total_ct = x_ct + y_ct;
-	printf("    %d + %d = %d gridlines drawn\n", x_ct, y_ct, total_ct);
+	printf("    %d + %d = %d gridlines drawn, %d skipped for next unit\n", x_ct, y_ct, total_ct, lines_skipped_for_next_unit);
 #endif
+	
+	return lines_skipped_for_next_unit > 0;
 }
 
 #define GRID_MIN_PX_D 6.0
@@ -428,7 +433,8 @@ static void drawgrid(UnitSettings *unit, ARegion *ar, View3D *v3d, const char **
 				else
 					printf("largest unit\n");
 #endif
-				drawgrid_draw(ar, x, y, dx_scalar, skip_mod, pos, color, col2);
+				if (!drawgrid_draw(ar, x, y, dx_scalar, skip_mod, pos, color, col2))
+					break;
 			}
 		}
 	}
@@ -473,8 +479,8 @@ static void drawgrid(UnitSettings *unit, ARegion *ar, View3D *v3d, const char **
 
 		if (grids_to_draw == 2) {
 			UI_GetThemeColorBlend3ubv(TH_HIGH_GRAD, TH_GRID, dx / (GRID_MIN_PX_D * 6.0), col2);
-			drawgrid_draw(ar, x, y, dx, v3d->gridsubdiv, pos, color, col2);
-			drawgrid_draw(ar, x, y, dx * sublines, 0, pos, color, col);
+			if (drawgrid_draw(ar, x, y, dx, v3d->gridsubdiv, pos, color, col2))
+				drawgrid_draw(ar, x, y, dx * sublines, 0, pos, color, col);
 		}
 		else if (grids_to_draw == 1) {
 			drawgrid_draw(ar, x, y, dx, 0, pos, color, col);