Blender Git Loki

Clear debug_data pointer in local cloth modifier data of the particle
systems on blend file load.

Partial response force for hair collisions.

This implements a penalty force as well as a repulsion force to avoid
further penetration, as suggested in
"Simulating Complex Hair with Robust Collision Handling"
(http://graphics.snu.ac.kr/publications/2005-choe-HairSim/Choe_2005_SCA.pdf)

Friction forces are still missing. More problematic is handling of
moving colliders, when face swap places with the hair vertex and a
collision is missed, putting the vertex inside the mesh volume. Larger
margins might help, but ultimately using Bullet collision detection is
probably more reliable and failsafe.

Debug drawing for simulations, to aid in visualizing abstract data such
as forces, velocities, contact points etc.

This uses a hash table to store debug elements (dots, lines, vectors at
this point). The hash table allows continuous display of elements that
are generated only in certain time steps, e.g. contact points, while
avoiding massive memory allocation. In any case, this system is really
a development feature, but very helpful in finding issues with the
internal solver data.

Some initial collision code, without actual response forces still.

This is still using the old BVH tree collision methods to generate
contact points, similar to what cloth does. This should be replaced
by a Bullet collision check, but generating contacts in this way is
easier for now, and lets us test responses and stability (although in
more complex collision cases the BVH method fails utterly, beside being
terribly inefficient with many colliders).

Implemented internal hair pressure to prevent hair from collapsing in
on itself.

This uses the same voxel structure as the hair smoothing algorithm.
A slightly different method was suggested in the original paper
(Volumetric Methods for Simulation and Rendering of Hair), but this is
based on directing hair based on a target density, which is another
way of implementing global goals. Our own approach is to define a
pressure threshold above which the hair is repelled in the density
gradient direction to simulate internal pressure from collisions.

Fixed hair velocity smoothing.

This is an important hair interaction feature that simulates friction
between hairs in an efficient way. The method is based on the paper
"Volumetric Methods for Simulation and Rendering of Hair"
( http://graphics.pixar.com/library/Hair/paper.pdf )

It was partially implemented already, but didn't work in this simplified
version. The same voxel structure can be used for implemeting repelling
forces on hair based on density, which can help a hair system maintain
volume instead of collapsing in on itself.

Support for various data properties of the hair grid in the voxel
texture.

Fixed voxel grid initialization from hair points and colliders by using
the suggested tent function from the original paper.

Plain float->int conversion for the grid location otherwise leads to
skewed data and unnecessary loss of information.

New voxel texture mode "Hair", for displaying the internal hair volume
structure as a texture.

This is mostly a debugging feature that may be removed again later.

Code cleanup: Use a variable-sized array for the hair volume velocity
smoothing and collision code, split into multiple functions.

Fix for Trusted option, loading new file

Would use the setting of the previously loaded file, now re-initialize from preferences.

Fix glitch in view-axis (order of drawing)

Fix UI glitches drawing text at different sizes

Font height was ignoring DPI in some cases (camera-name & eyedropper).

UI: cleanup UI_fontstyle_string_width, UI_draw_string

Both were maked as temp, but used often.

Now pass uiFontStyle to both, rename UI_draw_string to UI_fontstyle_draw_simple,
since its a variant of UI_fontstyle_draw that skips shadow, align... etc.

BLF: remove paranoid checks for unset default font

Fix T42212: Singular reflection pass is incorrect in regular path tracer

Issue seems to be caused by not totally proper pdf and eval values for this
closure. Changed it so they reflect to ggx/beckmann reflection with roughness
set to 0, which is effectively the same as the sharp reflection.

I18n tools minor update.

D627: Memory usage optimization for the compositor.

The compostor used a fixed size of 4 floats to hold pixel data. this
patch will select size of a pixel based on its type.
It uses 1 float for Value, 3 float for vector and 4 floats for color
data types.

When benchmarking on shots (opening shot of caminandes) we get a
reduction of memory of 30% and a tiny speedup as less data
transformations needs to take place (but these are negligable.

More information of the patch can be found on
https://developer.blender.org/D627 and
http://wiki.blender.org/index.php/Dev:Ref/Proposals/Compositor2014_p1.1_TD

Developers: jbakker & mdewanchand
Thanks for Sergey for his indept review.

Fix two potential bugs reported by latest coverity scan.

Fix a crasher in recent own mesh remap code ('island' area... :/ ).