Bugreport #4787 mentioned subpixel render issues, especially for small

images (like used for rendering icons).

When working during Orange on new render pipeline, I've left this topic
alone for a while... subpixel precision testing is very time consuming and
needs concentration for a while. :)

This commit brings back precision as it was for 2.41. Below a short
explanation of the solved issues.

- the window matrix for rendering is kept constant during all OSA passes,
  this to ensure clipping happens for each pass identically.
- a subpixel offset is only applied on filling in the z-buffer
- this offset is inverse corrected for shadepixel code, only on 2 places

Another nasty issue is that for filtered rendering (gauss etc), the tiles
(or entire image) is temporally increased 2 pixel in size. This caused a
'dark' (or sky color) edge on the rendering. During Orange that was solved
with a hardcoded clipping offset value, which only corrected for larger
pictures (like > 500 pixels in size).
Now this clipping offset is correctly calculated, based on render size.

Last issue: the view border in 3d window was calculated using integers,
giving small errors in display too. Now it uses float, so visually the
view border is more close to what a render shows.

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/src/edit.c b/source/blender/src/edit.c
index c48539ba736..bad89da633f 100644
--- a/source/blender/src/edit.c
+++ b/source/blender/src/edit.c
@@ -247,7 +247,7 @@ int get_border(rcti *rect, short flag)
 						BMF_DrawString(G.fonts, str);
 					}
 					else if(G.vd->persp==2) {
-						rcti vb;
+						rctf vb;
 	
 						calc_viewborder(G.vd, &vb);