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, 1 insertions, 1 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_instance.cc b/source/blender/draw/engines/eevee/eevee_instance.cc
index 8cf3931b005..fad6b1d6115 100644
--- a/source/blender/draw/engines/eevee/eevee_instance.cc
+++ b/source/blender/draw/engines/eevee/eevee_instance.cc
@@ -158,7 +158,7 @@ void Instance::object_sync(Object *ob)
         GPUBatch **mat_geom = DRW_cache_object_surface_material_get(
             ob, material_array.gpu_materials.data(), material_array.gpu_materials.size());
 
-        for (auto i : IndexRange(ob->totcol)) {
+        for (auto i : material_array.gpu_materials.index_range()) {
           if (mat_geom[i] == nullptr) {
             continue;
           }