EEVEE Next: Ensure correct material settings are used

Add Material::blend_flags to Shaderkey,
to ensure Materials with different settings but the same shader
don't end up using the same pass.

Pull Request: https://projects.blender.org/blender/blender/pulls/108283

source/blender/draw/engines/eevee_next/eevee_material.cc

@@ -203,7 +203,7 @@ MaterialPass MaterialModule::material_pass_get(Object *ob,
     matpass.sub_pass = nullptr;
   }
   else {
-    ShaderKey shader_key(matpass.gpumat, geometry_type, pipeline_type);
+    ShaderKey shader_key(matpass.gpumat, geometry_type, pipeline_type, blender_mat->blend_flag);
 
     PassMain::Sub *shader_sub = shader_map_.lookup_or_add_cb(shader_key, [&]() {
       /* First time encountering this shader. Create a sub that will contain materials using it. */

source/blender/draw/engines/eevee_next/eevee_material.hh

@@ -108,7 +108,7 @@ static inline eMaterialGeometry to_material_geometry(const Object *ob)
 
 /** Unique key to identify each material in the hash-map. */
 struct MaterialKey {
-  Material *mat;
+  ::Material *mat;
   uint64_t options;
 
   MaterialKey(::Material *mat_, eMaterialGeometry geometry, eMaterialPipeline surface_pipeline)
@@ -145,10 +145,14 @@ struct ShaderKey {
   GPUShader *shader;
   uint64_t options;
 
-  ShaderKey(GPUMaterial *gpumat, eMaterialGeometry geometry, eMaterialPipeline pipeline)
+  ShaderKey(GPUMaterial *gpumat,
+            eMaterialGeometry geometry,
+            eMaterialPipeline pipeline,
+            char blend_flags)
   {
     shader = GPU_material_get_shader(gpumat);
-    options = shader_uuid_from_material_type(pipeline, geometry);
+    options = blend_flags;
+    options = (options << 6u) | shader_uuid_from_material_type(pipeline, geometry);
     options = (options << 16u) | shader_closure_bits_from_flag(gpumat);
   }