Blender Git Loki

Fix issue with sculpting and SSAO.

We need to enable stenciling on the compositing FBO or we can clear
areas we don't want to clear and cause invalid depth values.

Restore texture coordinates properly

Merge branch 'master' into viewport_experiments

Fix for flickering, recreate the framebuffer textures in that case
(looks like it's the only way to have matching per pixel results too)

Move GPU compositing to its own file.

Also avoid recreating the framebuffers and gpu/color textures each
frame.

Happiness :)

There are still some glithes when scaling the areas, I'll look at those
next.

Minor fix when gravity code is disabled.

SSAO

* Expose attenuation value - allows to change influence of far objects
* Change influence of far objects to quadratic, eliminates some extreme
fringing from far occluding surfaces.

SSAO shader.

This works by using the calculated view space normal and accumulating
coverage of a certain area by nearby pixels. There are two sliders to
control the effect:

* Scale controls the area around each pixel that the shader "collides"
against
* Darkening scales the occlusion effect.

The effect works, but due to the way the normals are calculated, the
normals are never smooth shaded (that would require a separate render
target to store them) and the edges or polygons can be too apparent.
This is not really fixable at the moment unless we move to deferred
pipeline.

The FX system is stll not well optimized and rendering does not always
work correctly, but it's good to have this out for people to play with.

Removed unused code.

Added a calculation function for the fictitious forces introduced by
moving hair root reference frames.

This calculates Euler, Coriolis and Centrifugal forces which result
from describing hair in a moving reference frame.
http://en.wikipedia.org/wiki/Fictitious_force

Fix for own misconception of fictitious forces in the moving hair root
frames.

These forces don't have to be calculated for each individual
contribution. Rather they can be split off and be calculated on top of
the basic force vector rotation (todo).

Added back spring force definitions outside the implicit solver.

There are currently 3 types of springs: basic linear springs, goal
springs toward a fixed global target (not recommended, but works) and
bending springs.

These are agnostic to the specific spring definition in the cloth system
so hair systems can use the same API without converting everything to
cloth first.

Main cloth force calculation function outside of implicit core code.

Still misses spring forces.

Hair volume calculation is now in its own file.

Code is currently disabled until the other main forces are in place.

Moved the unused goal force calculation function to the main mass-spring
source file.

Moved most of the main cloth solver function out of implicit code core.

Force calculation is disabled, will follow shortly.

Moved init/free functions for solver data out of implicit core.

This also initializes spring matrix indices (off-diagonal 3x3 blocks),
which now uses a new API function.

Moved "set_positions" for cloth out of core implicit solver.

API for the solver now has functions for setting of vertex motion state
and the associated root transform data.

Renamed functions to make them explicitly refer to cloth, and split the
create/free functions for solver data off from the cloth solver.

Moved the cloth solver code into a new subfolder/library inside Blender
code.

The implicit solver itself should remain agnostic to the specifics of
the Blender data (cloth vs. hair). This way we could avoid the bloated
data conversion chain from particles/hair to derived mesh to cloth
modifier to implicit solver data and back. Every step in this chain adds
overhead as well as rounding errors and a possibility for bugs, not to
speak of making the code horribly complicated.

The new subfolder is named "physics" since it should be the start of a
somewhat "unified" physics systems combining all the various solvers in
the same place and managing things like synchronized time steps.