Blender Git Loki

Subdivision of hair fibers for smoother shading.

Subdivision works on the parent strands for efficiency. The fibers lengths
are based on the final subdivided length of parents, so no changes to the
shader are required.

This would be nicer with a tesselation shader, but this feature is not
available in Blender 2.8.

Use a 2D texture for the hair interpolation data instead of 1D for larger number of hairs.

It turns out that 1D textures have the same size limit on their 1 axis as 2D textures.
This limits the potential number of hair dramatically, even though the actual size of
the texture is very small. Using a 2D texture and wrapping the index avoids this problem.

Default settings for hair edit mode tool settings.

Disable selection outline drawing on the object during hair edit mode.

Removed leftover hair fiber code from edit mode drawing (all in Eevee now).

Moved the hair fiber shader from strand edit mode into Eevee.

This allows the shader to use proper lighting from the standard Eevee shaders.

The code for interpolating hair strands is in a glsl library file to facilitate
use in other engines later.

Hair fiber (child hair) drawing during edit mode, with heavy GPU leveraging.

Hair drawing requires fairly large vertex buffers. Vertices also need to be interpolated
and displaced according to the control (parent) hairs and hair-style features like curling
and clumping.

Instead of doing this in advance on the CPU and uploading a large vertex buffer every frame,
this work can be done on the GPU for realtime display, because interpolation and displacement
are highly parallelizable. The vertex buffers then only need to be uploaded once (as long
as strand lengths remain the same). The vertex format can also be very lightweight, requiring
only a curve parameter and index (half the size needed for full positions).

For interpolating a buffer texture is used in the shader, which contains all information
about the control curves (parents) from which to interpolate final vertex positions.

Custom shaders for drawing strand selection.

Basic drawing code for hair edit mode in the new 2.8 draw engine system.

Merge branch 'blender2.8' into strand_editmode2.8

Merge branch 'master' into strand_editmode

Added "show_brush" option for hair edit settings, expected by common paint UI.

This setting has no effect yet for hair editing, but the UI script expects it.

Merge branch 'master' into strand_editmode

Fix for uninitialized v_mirr variable when using edge strokes with mirroring.

Merge branch 'master' into strand_editmode

Merge branch 'master' into strand_editmode

Merge branch 'mesh_samples' into strand_editmode

Merge branch 'master' into strand_editmode

Merge branch 'master' into mesh_samples

Replace the deprecated TessFace usage for mesh sampling by LoopTri.

Also make sure a valid generator instance for random sampling is always
returned, regardless of triangle counts.