Output in 2 buffers Normals, Specular Color and roughness.
This way we can raytrace in a defered fashion and blend the exact contribution of the specular lobe on top of the opaque pass.
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
Goal is to make them more modular, to allow more variants (variable
single-color, thickness, ...) to be added without having to
copy-and-change-one-line of whole chain of shaders.
Hashed Alpha transparency offers a noisy output but has the benefit of being correctly ordered. Noise can be attenuated with Multisampling / AntiAliasing.
This allow specialized shaders to redefine the closure interface to fit their needs.
For instance, Volumetric closure needs to pass more than one vec4 (absorption vec3, scattering vec3, anisotropy float).
Not a single node based shader was working since a recent merge from
master.
The merge brought changes from the principle bsdf shader where
unsupported gl_ProjectionMatrix was still being used.
Implement GTAO (Ground Truth Ambient Occlusion) which is a special case of Horizon Based Ambient Occlusion that is more physically accurate.
Also add a bent normal option to sample indirect irradiance (diffuse lighting) with the least occluded direction.
This special case function enables rendering to a miplevel while using the miplevels above as texture input.
This is needed for some algorithm (i.e. creating a min-max depth pyramid texture).
This makes the node menus aware of the Cycles/Eevee distinction, and
only show the relevant nodes for the current engine. Names have also
been changed to accomodate for the new output node system.
This makes Eevee consistent with Cycles, by having a single output node,
and multiple shader nodes that connect to it.
Note that node systems for Eevee saved before this will be missing the
output node, and thus will show an invalid material. This is easily
resolved by connecting the shader output to a new output node.
