GPU: Split gpu_shader_material into multiple files.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_world_normals.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_world_normals.glsl
new file mode 100644
index 00000000000..f9691beee6f
--- /dev/null
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_world_normals.glsl
@@ -0,0 +1,25 @@
+/* TODO : clean this ifdef mess */
+void world_normals_get(out vec3 N)
+{
+#ifndef VOLUMETRICS
+#  ifdef HAIR_SHADER
+  vec3 B = normalize(cross(worldNormal, hairTangent));
+  float cos_theta;
+  if (hairThicknessRes == 1) {
+    vec4 rand = texelFetch(utilTex, ivec3(ivec2(gl_FragCoord.xy) % LUT_SIZE, 2.0), 0);
+    /* Random cosine normal distribution on the hair surface. */
+    cos_theta = rand.x * 2.0 - 1.0;
+  }
+  else {
+    /* Shade as a cylinder. */
+    cos_theta = hairThickTime / hairThickness;
+  }
+  float sin_theta = sqrt(max(0.0, 1.0 - cos_theta * cos_theta));
+  N = normalize(worldNormal * sin_theta + B * cos_theta);
+#  else
+  N = gl_FrontFacing ? worldNormal : -worldNormal;
+#  endif
+#else
+  generated_from_orco(vec3(0.0), N);
+#endif
+}