Blender Git Loki

UI: show warning when overwriting an export file

Replace char * with string in texture map types.

Review update rB827869a45bccbf1e016580b#271046 (by Jacques Lucke)

As mentioned in his comments, `Map` will do a pointer comparison for
`char *` keys. So string would be better. Even though the `lookup` has
been removed, `std::string` is still okay.

Also instead of iterating over `Map.keys()`, and then looking up value,
now it's iterating over a key-value pair: `Map<T, T>::item` of strings.

Minor comment changes.

Remove redundant blender:: from Vector, Map etc.

In rB96d6571073d3, `namespace blender` was added.

Fix compile error in recent commit

This was introduced in rBd7b10e5b740fe2.

Functions: add MutableAttributesRef data structure

This will be used to reference the content of a CustomData structure
in C++ code, that does not need to know who owns the data but only
works with it.

Fluid: Added display support for grid lines

Fix T78259: Proportional editing does not work in particle editing

And better identify what is bool and what is flag in the
proportional edit properties.

Add texture transform options, Blender version comment.

Two texture transform options, out of several, are supported now:
- Translation (origin offset) (syntax: "-o u v w")
- Scale (syntax: "-s u v w")

For Normal Map textures, Strength (bump multiplier) (syntax: "-bm s")
is also added.

I had to temporarily replace `nodeFindSocket` with its own
implementation to be able to build, since it doesn't accept
`const bNode*` which we're using everywhere.

I proposed a simple fix: D8142 for that. If and when it gets committed,
I'll remove the duplicate code.

Blender version string is also added in the MTL file.

Test file: {F8647881}

UI: Better Grouping of FFmpeg audio settings

Some audio render settings were hidden in the scene properties. These
settomgs belong in the render properties as they affect the output when
using ffmpeg video.

Fixes T49241

Differential Revision: https://developer.blender.org/D8137

Custom Menu: add submenu item

Revert "Fix T78259: Proportional editing does not work in particle editing"

This reverts commit 5c48592ccde08e18d13255e89d09067d5dc0f771.
Ii introduced a stupid error.

Fix T78352

Fix T78337: Fix crash when use GPencil merge without materials

If the object hadn't material, the index of material was negative.

LANPR: GP Lineart modifier file r/w now working.

LANPR: GP modifier basic UI complete.

Move code to namespace blender; clang-format

Merge branch 'master' into soc-2020-io-performance

Add support for exporting Material Library file

**Why not reuse the `write_mtl` in `export_obj.py` ?**
Because there are no benefits except saving some time now, only to later
waste it in debugging or extending it.
Having it in C++ provides easy extensibility when we need to
add more nodes' support without having to modify node_utils.py, which
itself is a hardcoded wrapper for BSDF and normal map shader nodes.

Quick Summary:
If export_params->export_materials is true, we create an empty MTL file
with the same name (not extension, of course) in the same directory.
`frame_writer` writes its name (with extension) to the OBJ file, to
reference it, as per format specs.

MTLWriter class is added in the new files. It uses NodeTreeRef committed
recently in rBe1cc9aa7f281 for a faster way to find two linked sockets.

`frame_writer` instantiates an MTLWriter for an object which then
*appends* that object's material to the previously created MTL file.

LANPR: Modifier properties added.

GPencil: Fix selection

Cleanup: make it easier to check if a CPPType is a specific compile time type