Blender Git Loki

Remove self collision quality (integrated with object collision)

Self collisions are now impulse based, and utilize the same solver as
the object collisions. Having separate quality controls would cause
issues when self and object collisions occur simultaneously.

Remove old repulsion stuff

Repulsions were long unused, and are now more obsolete than ever, with
the more stable collision response.

Remove unused functions in collision.c

Move fricion to collider object settings

New self collision implementation (needs some cleanup)

Fix stability issue and further make collisions inelastic

The repulse when colliding points are approaching was being scaled
incorrectly by the impulse, causing some undesired elasticity in the
collision. I imagine this was a workaround to avoid penetrations
because the collision responce was being calculated with respect to
the incorrect state, but this is no longer necessary now that that has
been fixed. (had missed this case in my previous elasticity commit)

Other than that, I have bary interpolated the static repulses to avoid a
nasty instability issue in some corner cases.

Fix collision distance calculation (makes collisions perfectly inelastic)

Collision distance was computed with respect to the positions before the
pre-collision solve, but should rather be computed with respect to the
newly solved positions.

This fixes the issue of the collisions being semi-elastic (bouncy),
making them pretty much perfectly inelastic. This also improves the
effectiveness of the collision response, preventing penetrations even
with far less collision steps.

Implement single sided collisions

Fix collision response scalings (had missed a few before)

Make caching a bit more sane (fixes plasticity issue)

This cleans up the cloth caching logic a bit.

Now, a simulation step only occurs if the current time is exactly one
frame after the last simulated step, thus preventing time gaps and
runtime data corruption. Also, now the cloth is only re-initialized
if the cache is actually outdated, instead of always being reset when
on the first frame.

This solves a bug where the cache was freed when moving the time to
a point within the cached period.

These changes also fix the issue of non-cached runtime simulation state
properties (e.g. plasticity) being reset when going to the first frame
or retaining a future state when simulating over an existing cache with
time gaps.

Apply collision responce on state before pre-collision solve (breaks selfcol)

This uses the pre-collision solve result only to find the collisions and
calculate the responce impulses, but rolls back to before the
pre-collision solve when it is time to actually apply the responce.

This prevents the cloth from undergoing a double solve per time-step,
which essentially made colliding clothes move much faster than
non-colliding clothes.

Remove weird impulse scaling

Fix collision extra solve update and remove redundant result applies

UI Cleanup: Add new property scaling panel

UI Cleanup: Add dedicated cloth shape panel

UI Cleanup: Separate object collisions from self collisions

UI Cleanup: Reorganize main cloth panel and improve tool-tips

Also removed the "vel_damping" option from the UI, because it sucks,
and nobody shall ever use, or speak of it again. (though I left its
implementation and RNA definition, for historic reasons perhaps?)

UI Cleanup: Remove cloth pin flag

UI Cleanup: Separate shrinking from sewing

UI Cleanup: Remove scaling flag