Eeshlo AO patch, revised

- Ambient Occlusion is a more sophisticated ambient trick, which takes
  nearby faces into account by firing a hemisphere of shadow-rays
  around. AKA 'dirt shader'.
- Eeshlo made it a Lamp type, which doesn't fit well. I've moved the
  settings to the World menu, and let the Material->ambient value control
  the amount it contributes
- currently, the AO value is added/subtracted/mixed with the 'diffuse'
  factor while shading, before it is multiplied with Material color

Buttons are in new Panel 'Amb Occ" in F8 menu. Note:

- "Dist:" by shortening the length of rays you get subtler effects and it
  renders faster too
- "DistF:" the attennuation factor gives control over how the 'shadow'
  spreads out.

Further it's just raytracing, so tends to be slooooow.... :)
Here same tricks as for other raytraced scenes apply, especially try to
keep the environment as small as possible (exclude faces from Octree by
giving them no Material Traceable).

I still have to think over a couple of aspects, will await feedback on it:
- AO color? Now it just adds 'white'
- other sampling patterns? I tried dithering, which was so-so
- method of controlling final 'samples' in F10? Might be useful for other
  oversampling too (area light) to have it reacting to a percentage or so..

1 files changed, 8 insertions, 0 deletions

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 4797e85d2f4..9f6ba376180 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -4119,6 +4119,7 @@ static void do_versions(Main *main)
 	}
 	if(main->versionfile <= 232) {	
 		Tex *tex= main->tex.first;
+		World *wrld= main->world.first;
 		
 		while(tex) {	
 			/* copied from kernel texture.c */
@@ -4138,6 +4139,13 @@ static void do_versions(Main *main)
 			
 			tex= tex->id.next;
 		}
+		
+		while(wrld) {
+			if(wrld->aodist==0.0) wrld->aodist= 10.0;
+			if(wrld->aosamp==0.0) wrld->aosamp= 5;
+			wrld= wrld->id.next;
+		}
+		
 	}