GPU: Make nodetree GLSL Codegen render engine agnostic

This commit removes all EEVEE specific code from the `gpu_shader_material*.glsl`
files. It defines a clear interface to evaluate the closure nodes leaving
more flexibility to the render engine.

Some of the long standing workaround are fixed:
- bump mapping support is no longer duplicating a lot of node and is instead
  compiled into a function call.
- bump rewiring to Normal socket is no longer needed as we now use a global
  `g_data.N` for that.


Closure sampling with upstread weight eval is now supported if the engine needs
it.

This also makes all the material GLSL sources use `GPUSource` for better
debugging experience. The `GPUFunction` parsing now happens in `GPUSource`
creation.

The whole `GPUCodegen` now uses the `ShaderCreateInfo` and is object type
agnostic. Is has also been rewritten in C++.

This patch changes a view behavior for EEVEE:
- Mix shader node factor imput is now clamped.
- Tangent Vector displacement behavior is now matching cycles.
- The chosen BSDF used for SSR might change.
- Hair shading may have very small changes on very large hairs when using hair
  polygon stripes.
- ShaderToRGB node will remove any SSR and SSS form a shader.
- SSS radius input now is no longer a scaling factor but defines an average
  radius. The SSS kernel "shape" (radii) are still defined by the socket default
  values.

Appart from the listed changes no other regressions are expected.

1 files changed, 25 insertions, 36 deletions

diff --git a/source/blender/nodes/shader/nodes/node_shader_bsdf_principled.cc b/source/blender/nodes/shader/nodes/node_shader_bsdf_principled.cc
index ba98a797f2a..a63c7aede04 100644
--- a/source/blender/nodes/shader/nodes/node_shader_bsdf_principled.cc
+++ b/source/blender/nodes/shader/nodes/node_shader_bsdf_principled.cc
@@ -103,6 +103,7 @@ static void node_declare(NodeDeclarationBuilder &b)
   b.add_input<decl::Vector>(N_("Normal")).hide_value();
   b.add_input<decl::Vector>(N_("Clearcoat Normal")).hide_value();
   b.add_input<decl::Vector>(N_("Tangent")).hide_value();
+  b.add_input<decl::Float>(N_("Weight")).unavailable();
   b.add_output<decl::Shader>(N_("BSDF"));
 }
 
@@ -128,8 +129,6 @@ static int node_shader_gpu_bsdf_principled(GPUMaterial *mat,
                                            GPUNodeStack *in,
                                            GPUNodeStack *out)
 {
-  GPUNodeLink *sss_scale;
-
   /* Normals */
   if (!in[22].link) {
     GPU_link(mat, "world_normals_get", &in[22].link);
@@ -145,36 +144,17 @@ static int node_shader_gpu_bsdf_principled(GPUMaterial *mat,
   if (!in[24].link) {
     GPUNodeLink *orco = GPU_attribute(CD_ORCO, "");
     GPU_link(mat, "tangent_orco_z", orco, &in[24].link);
-    GPU_link(mat,
-             "node_tangent",
-             GPU_builtin(GPU_WORLD_NORMAL),
-             in[24].link,
-             GPU_builtin(GPU_OBJECT_MATRIX),
-             &in[24].link);
+    GPU_link(mat, "node_tangent", in[24].link, &in[24].link);
   }
 #endif
 
   bool use_diffuse = socket_not_one(6) && socket_not_one(17);
-  bool use_subsurf = socket_not_zero(1) && use_diffuse && node->sss_id > 0;
+  bool use_subsurf = socket_not_zero(1) && use_diffuse;
   bool use_refract = socket_not_one(6) && socket_not_zero(17);
+  bool use_transparency = socket_not_one(21);
   bool use_clear = socket_not_zero(14);
 
-  /* SSS Profile */
-  if (use_subsurf) {
-    bNodeSocket *socket = (bNodeSocket *)BLI_findlink(&node->original->inputs, 2);
-    bNodeSocketValueRGBA *socket_data = (bNodeSocketValueRGBA *)socket->default_value;
-    /* For some reason it seems that the socket value is in ARGB format. */
-    GPU_material_sss_profile_create(mat, &socket_data->value[1]);
-  }
-
-  if (in[2].link) {
-    sss_scale = in[2].link;
-  }
-  else {
-    GPU_link(mat, "set_rgb_one", &sss_scale);
-  }
-
-  uint flag = GPU_MATFLAG_GLOSSY;
+  eGPUMaterialFlag flag = GPU_MATFLAG_GLOSSY;
   if (use_diffuse) {
     flag |= GPU_MATFLAG_DIFFUSE;
   }
@@ -182,28 +162,37 @@ static int node_shader_gpu_bsdf_principled(GPUMaterial *mat,
     flag |= GPU_MATFLAG_REFRACT;
   }
   if (use_subsurf) {
-    flag |= GPU_MATFLAG_SSS;
+    flag |= GPU_MATFLAG_SUBSURFACE;
+  }
+  if (use_transparency) {
+    flag |= GPU_MATFLAG_TRANSPARENT;
+  }
+
+  if (use_subsurf) {
+    bNodeSocket *socket = (bNodeSocket *)BLI_findlink(&node->original->inputs, 2);
+    bNodeSocketValueRGBA *socket_data = (bNodeSocketValueRGBA *)socket->default_value;
+    /* For some reason it seems that the socket value is in ARGB format. */
+    use_subsurf = GPU_material_sss_profile_create(mat, &socket_data->value[1]);
   }
 
-  float f_use_diffuse = use_diffuse ? 1.0f : 0.0f;
-  float f_use_clearcoat = use_clear ? 1.0f : 0.0f;
-  float f_use_refraction = use_refract ? 1.0f : 0.0f;
   float use_multi_scatter = (node->custom1 == SHD_GLOSSY_MULTI_GGX) ? 1.0f : 0.0f;
+  float use_sss = (use_subsurf) ? 1.0f : 0.0f;
+  float use_diffuse_f = (use_diffuse) ? 1.0f : 0.0f;
+  float use_clear_f = (use_clear) ? 1.0f : 0.0f;
+  float use_refract_f = (use_refract) ? 1.0f : 0.0f;
 
-  GPU_material_flag_set(mat, (eGPUMatFlag)flag);
+  GPU_material_flag_set(mat, flag);
 
   return GPU_stack_link(mat,
                         node,
                         "node_bsdf_principled",
                         in,
                         out,
-                        GPU_constant(&f_use_diffuse),
-                        GPU_constant(&f_use_clearcoat),
-                        GPU_constant(&f_use_refraction),
+                        GPU_constant(&use_diffuse_f),
+                        GPU_constant(&use_clear_f),
+                        GPU_constant(&use_refract_f),
                         GPU_constant(&use_multi_scatter),
-                        GPU_constant(&node->ssr_id),
-                        GPU_constant(&node->sss_id),
-                        sss_scale);
+                        GPU_uniform(&use_sss));
 }
 
 static void node_shader_update_principled(bNodeTree *ntree, bNode *node)