For users that means you can tweak shaders in the nodetree and things
are way faster. This is a huge improvement, particularly in
systems that have no shader cache.
From the code perspective it means we are no longer re-compiling the
shader every time a value is tweaked in the UI. We are using uniforms
for those values.
It would be slow to add that many uniforms for all the shaders. So
instead we are using UBO (Uniform Buffer Objects).
This fixes the main issue of T51467. However GWN_shaderinterface_create() still
needs to be improvedi. When opening a .blend all shaders are compiled once, so
optimizing it will bring a measurable impact.
========================================================================
NOTE: This breaks update of Cycles material upon nodetree nodes
tweaking. It will be fixed separately by depsgraph, once tackling T51925
(Animated Eevee values slowdown).
The idea is to make Depsgraph update more granular. The XXX TODO in
rna_nodetree.c will be tackled at that time as well.
========================================================================
Reviewers: sergey, brecht, fclem
Differential Revision: https://developer.blender.org/D2739
Hashed Alpha transparency offers a noisy output but has the benefit of being correctly ordered. Noise can be attenuated with Multisampling / AntiAliasing.
UVs need specific data in the VBO, which is not computed unless the
shaders assigned to the mesh actually use UVs. When adding UVs to the
shader, the VBOs were not being recomputed to include the required data.
This adds a DEG relation between the shader and the mesh, and recomputes
the required data if the shader changed.
Thanks Sergey, for all the DEG stuff...
A pointer to the uniform data for the empty drawing was being freed
before the actual draw call, which invalidates the uniform.
This makes the data only be freed after drawing.
It's cause by degenerate triangle having normals set to (0,0,0) which may not be compressed like it should.
This fix the problem in the final indirect lighting evaluation which might be costly.
This makes no sense to add theses. In cycles, each volume node is computed separatly. In eevee only the combined parameters are evaluated and phase should be averaged in this case.
