Blender Git Loki

Cycles: code refactoring to deduplicate the various BVH traversal variations.
Now there is a single BVH traversal code with #ifdefs for various features.
At runtime it will then select the appropriate variation to use depending if
instancing, hair or motion blur is in use.

This makes scenes without hair render a bit faster, especially after the
minimum width feature was added. It's not the most beautiful code, but we can't
use c++ templates and there were already 4 copies, adding 4 more to handle the
hair case separately would be too much.

Turn OpenMP on for MinGW, it works the 32 bit compiler.

Fix thumbnails not appearing on MinGW64, was actually a mistake on
MinGW-w64 headers (where _stat is actually _stati64), but since we
recommend a specific compiler build it's OK for now. Also tweaked other
places where _wstat is used.

Fix for #34911, Compositor with multiple views autozooms to node when creating a link. In order to allow node trees have different offsets in different editor instances, the view_center is now stored primarily in the bNodeTreePath struct for each tree in a node space. The view_center in bNodeTree is only used as an initial setting when opening a node group or switching node trees.

Fix for node editor lib_link and memfile restore (undo): The snode->nodetree/first tree path pointer was not properly mapped on file load due to the fact that it's stored locally in other ID data blocks. Undo was restoring the pointer correctly, but used an ugly hack. Now the SpaceNode->id pointer is linked first, then the datablock is checked for an internal node tree, which is then used instead of trying to lib-link the node tree pointer.

Cycles: initialize LCG for sss and hair sampling without using the sobol sampler,
slightly faster but also fixes the u/v sampling dimensions not longer being at even
values which is needed for best results.

Fix #35004: fireflies with .tif image in cycles, try to avoid extreme values when
openimageio can't detect premul/straight alpha correct.

Fix for render results acquire/release in viewport render, should only release
after drawing to be thread safe.

Bug fix #34974

The open region indicator (with +) didn't do alpha blending properly, so it wasn't
visible for any theme color.

Cycles Hair: Corrected own stochastic hair rng mistake and removed an unnecessary padding variable

- Corrected the Sobol dimension and removed a pad variable in Curve Struct.

Don't use auto vectorization for MinGW-w64. It may be a source for
trouble. Also fixed a few harmless warnings.

display options to help with 3d printing.

editmesh debug info,
- overhang (with axis angle options)
- wall thickness (with min/max distance)
- self-intersections.

access below 'Mesh Display' panel.

Added back the basic Search operator to the node Add menu. This operator should be implemented a bit nicer using the new categories system as well, but for now works just as before.

add function BKE_bmbvh_find_face_segment()
given a segment, finds finds an intersecting faces from the first point to the second, needed for checking self intersections (not used yet).

code cleanup: bmesh bvh
- remove unused members from BMBVHTree
- move per-raycast vars from BMBVHTree into per-callback structs (weren't threadsafe).
- simplify BKE_bmbvh_find_vert_closest().

add interp_v3_v3v3v3_uv() to use for use with uv value from isect_ray_tri_v3(), rename tree -> bmtree for BMBVHTree.

text editor reload no-longer resets scroll & cursor - annoying when making tweaks to UI scripts.
also restrict freestyle hack to WITH_FREESTYLE define.

style cleanup

Blender Internal Render in viewport

Because of our release soon, feature has been added behind the Debug Menu.
CTRL+ALT+D and set it to -1. Or commandline --debug-value -1.

When debug set to -1, you can put the viewport to 'render' mode, just like
for Cycles. Notes for testers: (and please no bugs in tracker for this :)

- It renders without AA, MBlur, Panorama, Sequence, Composite
- Only active render layer gets rendered. Select another layer will re-render.
- But yes: it works for FreeStyle renders!
- Also does great for local view.
- BI is not well suited for incremental renders on view changes. This only
works for non-raytrace scenes, or zoom in ortho or camera mode, or for
Material changes. In most cases a full re-render is being done.
- ESC works to stop the preview render.
- Borders render as well. (CTRL+B)
- Force a refresh with arrow key left/right. A lot of settings don't trigger
re-render yet.

Tech notes:

- FreeStyle is adding a lot of temp objects/meshes in the Main database. This
caused DepsGraph to trigger changes (and redraws). I've prepended the names
for these temp objects with char number 27 (ESC), and made these names be
ignored for tag update checking.

- Fixed some bugs that were noticable with such excessive re-renders, like
for opening file window, quit during renders.

Set min value for sampling value of freestyle line geometry modifier to 0.

Negative sampling does not make any sense and leads to crash.