Bugfix for #2036

Backbuffer selection codes issue on OSX.
On some h/w configs, with "1000s of colors set", the drivers seem to round
colors up or down... whilst until now rounding always was just truncating
bits. This gives errors in writing color codes and reading it back.
The c code only changed for OSX. For other OS's and HW this test could be
done as well.

1 files changed, 45 insertions, 8 deletions

diff --git a/source/blender/src/mywindow.c b/source/blender/src/mywindow.c
index 1ef4e330107..b7d904af727 100644
--- a/source/blender/src/mywindow.c
+++ b/source/blender/src/mywindow.c
@@ -485,36 +485,72 @@ void mywindow(float x1, float x2, float y1, float y2, float n, float f)
 	bwin_frustum(curswin, x1, x2, y1, y2, n, f);
 }
 
+#ifdef __APPLE__
+
+/* apple seems to round colors to below and up on some configs */
+
 unsigned int index_to_framebuffer(int index)
 {
 	unsigned int i= index;
 
 	switch(mainwin_color_depth) {
-	case 8:
-		i= ((i & 48)<<18) + ((i & 12)<<12) + ((i & 3)<<6);
-		i |= 0x3F3F3F;
-		break;
 	case 12:
 		i= ((i & 0xF00)<<12) + ((i & 0xF0)<<8) + ((i & 0xF)<<4);
 		/* sometimes dithering subtracts! */
-		i |= 0x0F0F0F;
+		i |= 0x070707;
 		break;
 	case 15:
 	case 16:
 		i= ((i & 0x7C00)<<9) + ((i & 0x3E0)<<6) + ((i & 0x1F)<<3);
-		i |= 0x070707;
+		i |= 0x030303;
 		break;
 	case 24:
 		break;
-	default:	// 18 bits... not enuf
+	default:	// 18 bits... 
 		i= ((i & 0x3F000)<<6) + ((i & 0xFC0)<<4) + ((i & 0x3F)<<2);
-		i |= 0x030303;
+		i |= 0x010101;
 		break;
 	}
 	
 	return i;
 }
 
+#else
+
+/* this is the old method as being in use for ages.... seems to work? colors are rounded to lower values */
+
+unsigned int index_to_framebuffer(int index)
+{
+	unsigned int i= index;
+	
+	switch(mainwin_color_depth) {
+		case 8:
+			i= ((i & 48)<<18) + ((i & 12)<<12) + ((i & 3)<<6);
+			i |= 0x3F3F3F;
+			break;
+		case 12:
+			i= ((i & 0xF00)<<12) + ((i & 0xF0)<<8) + ((i & 0xF)<<4);
+			/* sometimes dithering subtracts! */
+			i |= 0x0F0F0F;
+			break;
+		case 15:
+		case 16:
+			i= ((i & 0x7C00)<<9) + ((i & 0x3E0)<<6) + ((i & 0x1F)<<3);
+			i |= 0x070707;
+			break;
+		case 24:
+			break;
+		default:	// 18 bits... 
+			i= ((i & 0x3F000)<<6) + ((i & 0xFC0)<<4) + ((i & 0x3F)<<2);
+			i |= 0x030303;
+			break;
+	}
+	
+	return i;
+}
+
+#endif
+
 int framebuffer_to_index(unsigned int col)
 {
 	if (col==0) return 0;
@@ -616,6 +652,7 @@ static int ov_x, ov_y, ov_sx, ov_sy;
 
 /*
 #if defined(__sgi) || defined(__sun) || defined(__sun__) || defined (__sparc) || defined (__sparc__)
+*/
 /* this is a dirty patch: gets sometimes the backbuffer */
 /* my_get_frontbuffer_image(0, 0, 1, 1);
 my_put_frontbuffer_image();