Blender Git Loki

Improve filtering across Ptex corners

Better method for updating adjacent Ptex borders

Move extern/ptex to intern/ptex

Merge remote-tracking branch 'origin/master' into cycles-ptex-49

Merge remote-tracking branch 'origin/master' into cycles-ptex-49

Consistently use "ptex_rects" instead of "ptex_regions"

First pass at fixing Ptex texpaint resolution undo/redo

Seems to work OK, but need to clean up the API to make it work
better. Want to make sure there are no unexpected issues first though.

Merge remote-tracking branch 'origin/master' into cycles-ptex-49

Conflicts:
source/blender/gpu/GPU_extensions.h

Improve Ptex filter border updates

- Texture paint looks better now

- Still need to fix corners

Expand Ptex paint redraw region to include filter border

Start using BPXRect for IMB ptex regions

Filter borders can now be calculated entirely with BPXRects and a
packed image. This should make it easier to unify some code paths and
also make partial updates while painting much simpler to implement.

TODO: fix BPX include in IMB_imbuf_types.h

Use BPXRect for internal storage in Ptex layout code

Code cleanup: simplify Ptex mesh-from-image functions

Add Ptex adjacency data to BPXRect

Ptex cleanup: rename BPXSide -> BPXRectSide

Code cleanup: use BPXRect in Ptex layout interface

Code cleanup: shuffling some Ptex declarations around

Merge remote-tracking branch 'origin/master' into cycles-ptex-49

Merge remote-tracking branch 'origin/master' into cycles-ptex-49

Remove incorrect conversion to float in Ptex