Blender Git Loki

Disable scope updates in texture and image paint modes.

Scope update is very slow for high resolutions, and currently blocks
the UI thread(!). This is especially terrible in paint modes, where
each stroke causes a scope update and unacceptable freezing.

The scopes update method tries to avoid this somewhat by skipping if the
toolbar is disabled, but this doesn't help when painting where brush
tools etc. are frequently needed. It's also a bad-level poll, with the
core system accessing a UI element.

Eventually scope updates should become a low-priority background job,
as well as becoming threaded. Until then this polling provides a usable
workaround to the most outrageous cases.

Curve-based control for "roughness" (noise displacement) of child hair.

Curve-based control for child path tapering.

This is an alternative method to the current fixed function with a
clump factor and "shape" parameter. This function is quite limited and
does not give the desired result in many cases (e.g. long, parallel
rasta strands are problematic). So rather than trying to add more
parameters there is now a fully user-defined optional curve for setting
the tapering shape.

Moved kink, clump and roughness functions into the dedicated source file.

Reorganizing hair child code a little bit to make it not totally insane.

This contains a few pieces of code for a future "modifier" system that
would allow more flexible combination of effects. Eventually a node
system is the way to go, but the current code makes that impossible.

Separate context freeing from task freeing in threaded particle updates
to prevent double-freeing/invalid mem access.

This can happen with the "virtual parents" feature, which generates both
parent and child paths. Each task free function also freed the shared
context, leading to double freeing.

Properly register the `mathutils.interpolate` submodule.

Fix for invalid access to undefined hair data in edge-only cloth meshes.

Cloth data is used both for hair and actual cloth, which makes things
really difficult. The face number was used for distinguishing the two
types (no faces == hair mesh), but the extra hair data necessary for
hair sim is generated by particles and not available for edge-only cloth
meshes. This really needs to be sanitized ...

Conflicts:
source/blender/physics/intern/BPH_mass_spring.cpp

Presets for hair dynamics.

This is necessary because the hair dynamics settings are not part of the
ParticleSettings datablock, but part of the convoluted cloth modifier
inside the particle system struct. In the future this will be recoded
properly, but in the meantime presets provide a simple an unobtrusive
way to have reusable dynamics settings for hair.

Conflicts:
release/scripts/startup/bl_ui/properties_particle.py

Radical simplification of the wind effect on hair, since the previous
approach does not work very well.

Using a cross section estimate still causes large oscillations due to
varying hair force based on angles. It also requires a sensible hair
thickness value (particle radius) which is difficult to control and
visualize at this point.

The new model is based purely on per-vertex forces, which seems to be
much more stable. It's also somewhat justified by the fact that each
hair vertex represents a certain mass.

Conflicts:
source/blender/physics/intern/BPH_mass_spring.cpp

Fix for wind force function call.

Improved force field effects on hair strands.

The previous calculation was modulated with the angle between the wind
direction and the segments, which leads to very oscillating behavior.

Now the formula includes an estimate for the geometric cross section
of a hair segment based on the incident angle and the hair thickness
(currently just the particle size). This gives a more stable behavior
and more realistic response to wind.

Conflicts:
source/blender/blenkernel/intern/particle_system.c
source/blender/physics/intern/BPH_mass_spring.cpp

New python submodule `mathutils.interpolate` for various mesh interpolation and weighting methods.

This module will contain mirrored functions for calculating and applying
weights for points on a mesh. This includes barycentric and UV weighting
and possibly more advanced global weighting such as harmonic weights.

The naming should follow this scheme:
<type>_{2d,3d}_{calc,apply}

e.g.
poly_2d_calc
poly_2d_apply
uv_3d_calc
...

Reviewers: campbellbarton

Differential Revision: https://developer.blender.org/D939

Fix for missing library linking in blenderplayer.

Another fix for particle instance child lookups, was not subtracting
parent amount.

Fix for invalid particle pointer access in mixed particle/child loop.

Better update function for particle settings affecting nested cloth
modifier.

Fix for applying the bending randomness factor.

A stupid hack is needed here, changing the way the factor is applied to
angular bending springs. In cloth sim the bending factor of individual
springs is applied as a mix value between the bending stiffness and a
max value, but this max value isn't even used in hair sim so that
approach becomes useless.

Conflicts:
source/blender/physics/intern/BPH_mass_spring.cpp

Randomness factor for hair bending stiffness.

This helps to create some variation in a hair system, which can
otherwise become very uniform and boring. It's yet another confusing
setting in a system that should have been nodified, but only option for
now (broken windows ...)

Conflicts:
source/blender/blenkernel/intern/particle_system.c
source/blender/physics/intern/BPH_mass_spring.cpp

Fix for particle instance initial frames.

These were not orthonormal and tended to flip with changing hair
direction, now use the particle hair matrix which is stable wrt. the
mesh surface.