Blender Git Loki

MTLWriter: overwrite the file instead of appending to it.

Prepend importer_ to mesh_utils; parser_ to string_utils.

Move MTLMaterial & float3_to_string to exporter files.

Keeping the branch in sync with D8754 and D8753.

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

Fix: add versioning to fix incorrectly written customdata

Reviewers: campbellbarton

Differential Revision: https://developer.blender.org/D8903

Cleanup: use uint8_t for various flags in curves

Previously, it was kind of a mess. In different places it was using `char`, `short` and `int`.

The changed properties are flags that are operated upon using bit operations. Therefore, the integer type should be unsigned. Since we only use 2 bits of these flags, `uint8_t` is large enough.

Especially note the change I had to make in `RNA_define.h` to make this work.

Reviewers: campbellbarton

Differential Revision: https://developer.blender.org/D8844

Merge remote-tracking branch 'origin/master' into lanpr-under-gp

# Conflicts:
# source/blender/makesdna/DNA_collection_types.h
# source/blender/makesrna/intern/rna_collection.c

Fix: Showing Meta Data Crash

When Showing Meta data for an image where the buffer does not exist
(missing file) it crashed. This patch removes the check on the image and
only checks the availability of the buffer.

Move vertex index Vector resize to OBJMesh.

Corrections: correct wrong assert, remove cast.

Simplify material group calculation.

Simplify vertex group calculation.

Add smooth group constants, use "0" instead of "off".

Add polygon element writer selector to OBJWriter.

Install_deps: update to add pugixml and potrace new deps.

Also fixed OpenVDB maximum version, it appears that even 7.1 is not
compatible with 7.0?

Re T80818 and D8628.

Fix T80800: Active UVMap Drawing

Regression introduced by D8234. In stead of using the active uv map, the
render uv map was drawn. This change will use the active uv map.

Add polygon normal indices calculation method to OBJMesh.

Remove depsgraph member variable; use const variables.

Material: Disambiguate mat_nr + 1.

Add method to free mesh; disambiguate triangulate method.