Blender Git Loki

Generate a number of "roots" for render hairs on the mesh surface.

These root points will be used as input for the strand shader to generate
the interpolated render strands.

Use the show_control_strands toggle for switching control hair display on/off.

Also use the basic edge shader for control hairs, the generated GLSL shader is
only needed for drawing render strands.

Intermediate struct StrandData for storing base data for drawing.

This is equivalent to the DerivedMesh stage in the Mesh -> DM -> GPUBuffer
pipeline. The Strands struct is the base editable user data, StrandsData
is preprocessed data with evaluated root matrices and applied for object
space drawing.

GPU code for vertex and edge buffers of strands.

This is a modification of the DerivedMesh code, which relies too much
on the DerivedMesh data structure to be used directly.

Test operator for quickly initializing the strands data.

This is just a temporary test operator, to be removed later when
edit mode and other mechanisms exist to generate useful strands.

Use plain vertex and curve arrays in Strands data, so that they can be used as OpenGL buffers.

Own file for strand drawing code to avoid polluting drawobject.c even more.

Skeleton GPU code for creating a special hair shader.

This will include a geometry shader as well as vertex/fragment shaders,
for efficiently generating strand geometry based on control strands.

Flag for enabling control strand display.

Currently still unused.

Use the Strands modifier as a simple container for strand control curves.

These curves are NOT intended for final rendering! They are abstract
editable data (control strands) from which the "actual" visible strands
have to be generated in some way.

This is largely equivalent to the parent/child dichotomy in old particles,
but enforces the separation right from the start (control curves are never
rendered).

Stub modifier for testing strand geometry generation.

Modifier is not ideal, but easiest way to test code due to lack of
infrastructure in Object for node-generated data.

Merge branch 'master' into mesh_samples

Merge branch 'master' into strand_editmode

Fix unused function warning.

Fix meamleak from unfreed edit data when exiting in hair edit mode.

Fix unfreed temporary buffers in strand relaxation.

Define BMEditStrands struct as an extension of BMEditMesh.

The advantage is that we can now use this struct in the (rather involved)
process of generating a display DerivedMesh and apply modifiers to it.

Disable regular mesh drawing in hair edit mode.

Proof-of-concept: Hair edit data from regular meshes.

This adds the possibility to edit a regular mesh like strand data.
It's more of a test for independence from particles than a real use case,
but could come in handy anyway.

Check mesh samples for zero weights on eval to detect invalid/unusable samples.