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, 44 insertions, 10 deletions

diff --git a/source/blender/gpu/intern/gpu_node_graph.h b/source/blender/gpu/intern/gpu_node_graph.h
index 5856001d548..024119e1c24 100644
--- a/source/blender/gpu/intern/gpu_node_graph.h
+++ b/source/blender/gpu/intern/gpu_node_graph.h
@@ -12,9 +12,15 @@
 #include "DNA_customdata_types.h"
 #include "DNA_listBase.h"
 
+#include "BLI_ghash.h"
+
 #include "GPU_material.h"
 #include "GPU_shader.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct GPUNode;
 struct GPUOutput;
 struct ListBase;
@@ -25,19 +31,18 @@ typedef enum eGPUDataSource {
   GPU_SOURCE_UNIFORM,
   GPU_SOURCE_ATTR,
   GPU_SOURCE_UNIFORM_ATTR,
-  GPU_SOURCE_BUILTIN,
   GPU_SOURCE_STRUCT,
   GPU_SOURCE_TEX,
   GPU_SOURCE_TEX_TILED_MAPPING,
   GPU_SOURCE_VOLUME_GRID,
   GPU_SOURCE_VOLUME_GRID_TRANSFORM,
+  GPU_SOURCE_FUNCTION_CALL,
 } eGPUDataSource;
 
 typedef enum {
   GPU_NODE_LINK_NONE = 0,
   GPU_NODE_LINK_ATTR,
   GPU_NODE_LINK_UNIFORM_ATTR,
-  GPU_NODE_LINK_BUILTIN,
   GPU_NODE_LINK_COLORBAND,
   GPU_NODE_LINK_CONSTANT,
   GPU_NODE_LINK_IMAGE,
@@ -47,15 +52,28 @@ typedef enum {
   GPU_NODE_LINK_VOLUME_GRID_TRANSFORM,
   GPU_NODE_LINK_OUTPUT,
   GPU_NODE_LINK_UNIFORM,
+  GPU_NODE_LINK_DIFFERENTIATE_FLOAT_FN,
 } GPUNodeLinkType;
 
+typedef enum {
+  GPU_NODE_TAG_NONE = 0,
+  GPU_NODE_TAG_SURFACE = (1 << 0),
+  GPU_NODE_TAG_VOLUME = (1 << 1),
+  GPU_NODE_TAG_DISPLACEMENT = (1 << 2),
+  GPU_NODE_TAG_THICKNESS = (1 << 3),
+  GPU_NODE_TAG_AOV = (1 << 4),
+  GPU_NODE_TAG_FUNCTION = (1 << 5),
+} eGPUNodeTag;
+
+ENUM_OPERATORS(eGPUNodeTag, GPU_NODE_TAG_FUNCTION)
+
 struct GPUNode {
   struct GPUNode *next, *prev;
 
   const char *name;
 
   /* Internal flag to mark nodes during pruning */
-  bool tag;
+  eGPUNodeTag tag;
 
   ListBase inputs;
   ListBase outputs;
@@ -70,8 +88,6 @@ struct GPUNodeLink {
   union {
     /* GPU_NODE_LINK_CONSTANT | GPU_NODE_LINK_UNIFORM */
     const float *data;
-    /* GPU_NODE_LINK_BUILTIN */
-    eGPUBuiltin builtin;
     /* GPU_NODE_LINK_COLORBAND */
     struct GPUTexture **colorband;
     /* GPU_NODE_LINK_VOLUME_GRID */
@@ -84,6 +100,8 @@ struct GPUNodeLink {
     struct GPUUniformAttr *uniform_attr;
     /* GPU_NODE_LINK_IMAGE_BLENDER */
     struct GPUMaterialTexture *texture;
+    /* GPU_NODE_LINK_DIFFERENTIATE_FLOAT_FN */
+    const char *function_name;
   };
 };
 
@@ -110,8 +128,6 @@ typedef struct GPUInput {
   union {
     /* GPU_SOURCE_CONSTANT | GPU_SOURCE_UNIFORM */
     float vec[16]; /* vector data */
-    /* GPU_SOURCE_BUILTIN */
-    eGPUBuiltin builtin; /* builtin uniform */
     /* GPU_SOURCE_TEX | GPU_SOURCE_TEX_TILED_MAPPING */
     struct GPUMaterialTexture *texture;
     /* GPU_SOURCE_ATTR */
@@ -120,6 +136,8 @@ typedef struct GPUInput {
     struct GPUUniformAttr *uniform_attr;
     /* GPU_SOURCE_VOLUME_GRID | GPU_SOURCE_VOLUME_GRID_TRANSFORM */
     struct GPUMaterialVolumeGrid *volume_grid;
+    /* GPU_SOURCE_FUNCTION_CALL */
+    char function_call[64];
   };
 } GPUInput;
 
@@ -129,14 +147,25 @@ typedef struct GPUNodeGraphOutputLink {
   GPUNodeLink *outlink;
 } GPUNodeGraphOutputLink;
 
+typedef struct GPUNodeGraphFunctionLink {
+  struct GPUNodeGraphFunctionLink *next, *prev;
+  char name[16];
+  GPUNodeLink *outlink;
+} GPUNodeGraphFunctionLink;
+
 typedef struct GPUNodeGraph {
   /* Nodes */
   ListBase nodes;
 
-  /* Main Output. */
-  GPUNodeLink *outlink;
+  /* Main Outputs. */
+  GPUNodeLink *outlink_surface;
+  GPUNodeLink *outlink_volume;
+  GPUNodeLink *outlink_displacement;
+  GPUNodeLink *outlink_thickness;
   /* List of GPUNodeGraphOutputLink */
   ListBase outlink_aovs;
+  /* List of GPUNodeGraphFunctionLink */
+  ListBase material_functions;
 
   /* Requested attributes and textures. */
   ListBase attributes;
@@ -145,6 +174,9 @@ typedef struct GPUNodeGraph {
 
   /* The list of uniform attributes. */
   GPUUniformAttrList uniform_attrs;
+
+  /** Set of all the GLSL lib code blocks . */
+  GSet *used_libraries;
 } GPUNodeGraph;
 
 /* Node Graph */
@@ -171,4 +203,6 @@ struct GPUTexture **gpu_material_ramp_texture_row_set(struct GPUMaterial *mat,
                                                       float *pixels,
                                                       float *row);
 
-struct GSet *gpu_material_used_libraries(struct GPUMaterial *material);
+#ifdef __cplusplus
+}
+#endif