We basically duplicate the height map branch plugged into the bump node,
and tag each node in each branch as dx/dy/ref using `branch_tag`.
Then we add a one pixel offset on the texture coordinates if the node is
tagged as dx or dy.
The dx/dy branches are plugged into (new) hidden sockets on the bump node.
This match cycles bump better but have a performance impact. Also, complex
nodetrees can now become instruction limited and not compile anymore.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D5531
This patch continue the efforts to split the `gpu_shader_material` file
started in D5569.
Dependency resolution is now recursive. Each shading node gets its own
file. Additionally, some utility files are added to be shared between
files, like `math_util`, `color_util`, and `hash`. Some files are always
included because they may be used in the execution function, like
`world_normals`.
Some glsl functions appeared to be unused, so they were removed, like
`output_node`, `bits_to_01`, and `exp_blender`. Other functions have
been renamed to be more general and get used as utils, like `texco_norm`
which became `vector_normalize`.
A lot of the opengl tests fails, but those same tests also fail in
master, so this is probably unrelated to this patch.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D5616
