GPU/EEVEE: Refactor codegen and nodetree support

This is the first step towards the new evaluation scheme of EEVEE
closures.

This commit contains:
- Removal of GPU_SOURCE_BUILTIN type, prefering global instead. This
  avoid many boilerplate code since most of the old builtins are now
  datas that are always present (i.e: view matrices, normals).
- Rewritting of codegen in C++ to use `std::stringstream`.
- Added a callback to let engine decide what to do with codegen code.
  This remove a lot of needs for defines because of code order
  dependency. The engine can insert the nodetree code in custom ways
  to create advance effects (i.e: add displacement or vertex lighting).
  Engine now returns final shader strings.
- Closure nodes evaluation replacment is a placeholder for now.

1 files changed, 4 insertions, 4 deletions

diff --git a/source/blender/draw/engines/eevee/shaders/eevee_surface_deferred_frag.glsl b/source/blender/draw/engines/eevee/shaders/eevee_surface_deferred_frag.glsl
index b83df1090ab..442ce6ee584 100644
--- a/source/blender/draw/engines/eevee/shaders/eevee_surface_deferred_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/eevee_surface_deferred_frag.glsl
@@ -12,13 +12,13 @@ layout(location = 3) out uvec4 out_volume_data;      /* Volume Emission, Absorpt
 layout(location = 4) out vec4 out_emission_data;     /* Emission. */
 layout(location = 5) out vec4 out_transparency_data; /* Transparent BSDF, Holdout. */
 
-GlobalData g_data;
-
 void main(void)
 {
-  g_data = init_from_interp();
+  g_data = init_globals();
+
+  ntree_eval_set_defaults();
 
-  nodetree_eval(g_data.N);
+  nodetree_surface();
 
   out_diffuse_data = gbuffer_store_diffuse_data(g_diffuse_data);
   out_reflection_data = gbuffer_store_reflection_data(g_reflection_data);