In glsl the clamp function has undefined behavior when min > max. For
the clamp node this resulted in differences between cycles and eevee.
This patch adds the expected implementation for minmax.
The old clamp function is still used in cases where we know for certain
that the input values are correct (math node clamp option). GPU uses
optimized code and silicon in these cases.
Modes: Linear interpolation (default), stepped linear, smoothstep and smootherstep.
This also includes an additional option for the **Clamp node** to switch between **Min Max** (default) and **Range** mode.
This was needed to allow clamping when **To Max** is less than **To Min**.
Reviewed By: JacquesLucke, brecht
Differential Revision: https://developer.blender.org/D5827
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
