EEVEE: Add new experimental "EEVEE Next" option

This is supposed to hold the latest improvement from the EEVEE rewrite branch.
Note that a restart is necessary in order for the engine to appear.

The registration code is a bit convoluted as it needs to be after the WM_init.

release/scripts/startup/bl_ui/space_userpref.py

@@ -2276,6 +2276,7 @@ class USERPREF_PT_experimental_prototypes(ExperimentalPanel, Panel):
                 ({"property": "use_new_curves_type"}, "T68981"),
                 ({"property": "use_new_point_cloud_type"}, "T75717"),
                 ({"property": "use_full_frame_compositor"}, "T88150"),
+                ({"property": "enable_eevee_next"}, "T93220"),
             ),
         )
 

source/blender/draw/CMakeLists.txt

@@ -129,6 +129,7 @@ set(SRC
   engines/eevee/eevee_subsurface.c
   engines/eevee/eevee_temporal_sampling.c
   engines/eevee/eevee_volumes.c
+  engines/eevee_next/eevee_engine.cc
   engines/workbench/workbench_data.c
   engines/workbench/workbench_effect_antialiasing.c
   engines/workbench/workbench_effect_cavity.c
@@ -210,6 +211,7 @@ set(SRC
   engines/eevee/eevee_lightcache.h
   engines/eevee/eevee_lut.h
   engines/eevee/eevee_private.h
+  engines/eevee_next/eevee_engine.h
   engines/external/external_engine.h
   engines/image/image_batches.hh
   engines/image/image_drawing_mode.hh

source/blender/draw/DRW_engine.h

@@ -37,6 +37,7 @@ struct bContext;
 struct rcti;
 
 void DRW_engines_register(void);
+void DRW_engines_register_experimental(void);
 void DRW_engines_free(void);
 
 bool DRW_engine_render_support(struct DrawEngineType *draw_engine_type);

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

@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2021 Blender Foundation.
+ */
+
+#include "BKE_global.h"
+#include "BLI_rect.h"
+
+#include "GPU_framebuffer.h"
+
+#include "ED_view3d.h"
+
+#include "DRW_render.h"
+
+typedef struct EEVEE_Data {
+  DrawEngineType *engine_type;
+  DRWViewportEmptyList *fbl;
+  DRWViewportEmptyList *txl;
+  DRWViewportEmptyList *psl;
+  DRWViewportEmptyList *stl;
+  void *instance;
+} EEVEE_Data;
+
+static void eevee_engine_init(void *vedata)
+{
+  UNUSED_VARS(vedata);
+}
+
+static void eevee_draw_scene(void *vedata)
+{
+  UNUSED_VARS(vedata);
+}
+
+static void eevee_cache_init(void *vedata)
+{
+  UNUSED_VARS(vedata);
+}
+
+static void eevee_cache_populate(void *vedata, Object *object)
+{
+  UNUSED_VARS(vedata, object);
+}
+
+static void eevee_cache_finish(void *vedata)
+{
+  UNUSED_VARS(vedata);
+}
+
+static void eevee_engine_free(void)
+{
+}
+
+static void eevee_instance_free(void *instance)
+{
+  UNUSED_VARS(instance);
+}
+
+static void eevee_render_to_image(void *UNUSED(vedata),
+                                  struct RenderEngine *engine,
+                                  struct RenderLayer *layer,
+                                  const struct rcti *UNUSED(rect))
+{
+  UNUSED_VARS(engine, layer);
+}
+
+static void eevee_render_update_passes(RenderEngine *engine, Scene *scene, ViewLayer *view_layer)
+{
+  UNUSED_VARS(engine, scene, view_layer);
+}
+
+static const DrawEngineDataSize eevee_data_size = DRW_VIEWPORT_DATA_SIZE(EEVEE_Data);
+
+extern "C" {
+
+DrawEngineType draw_engine_eevee_next_type = {
+    nullptr,
+    nullptr,
+    N_("Eevee"),
+    &eevee_data_size,
+    &eevee_engine_init,
+    &eevee_engine_free,
+    &eevee_instance_free,
+    &eevee_cache_init,
+    &eevee_cache_populate,
+    &eevee_cache_finish,
+    &eevee_draw_scene,
+    nullptr,
+    nullptr,
+    &eevee_render_to_image,
+    nullptr,
+};
+
+RenderEngineType DRW_engine_viewport_eevee_next_type = {
+    nullptr,
+    nullptr,
+    "BLENDER_EEVEE_NEXT",
+    N_("Eevee Next"),
+    RE_INTERNAL | RE_USE_PREVIEW | RE_USE_STEREO_VIEWPORT | RE_USE_GPU_CONTEXT,
+    nullptr,
+    &DRW_render_to_image,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    &eevee_render_update_passes,
+    &draw_engine_eevee_next_type,
+    {nullptr, nullptr, nullptr},
+};
+}

source/blender/draw/engines/eevee_next/eevee_engine.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2016 Blender Foundation. */
+
+/** \file
+ * \ingroup DNA
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern DrawEngineType draw_engine_eevee_next_type;
+extern RenderEngineType DRW_engine_viewport_eevee_next_type;
+
+#ifdef __cplusplus
+}
+#endif

source/blender/draw/intern/draw_manager.c

@@ -85,6 +85,7 @@
 
 #include "engines/basic/basic_engine.h"
 #include "engines/eevee/eevee_engine.h"
+#include "engines/eevee_next/eevee_engine.h"
 #include "engines/external/external_engine.h"
 #include "engines/gpencil/gpencil_engine.h"
 #include "engines/image/image_engine.h"
@@ -2898,6 +2899,13 @@ void DRW_engine_register(DrawEngineType *draw_engine_type)
   g_registered_engines.len = BLI_listbase_count(&g_registered_engines.engines);
 }
 
+void DRW_engines_register_experimental(void)
+{
+  if (U.experimental.enable_eevee_next) {
+    RE_engines_register(&DRW_engine_viewport_eevee_next_type);
+  }
+}
+
 void DRW_engines_register(void)
 {
   RE_engines_register(&DRW_engine_viewport_eevee_type);

source/blender/makesdna/DNA_userdef_types.h

@@ -650,7 +650,8 @@ typedef struct UserDef_Experimental {
   char use_extended_asset_browser;
   char use_override_templates;
   char use_named_attribute_nodes;
-  char _pad[2];
+  char enable_eevee_next;
+  char _pad[1];
   /** `makesdna` does not allow empty structs. */
 } UserDef_Experimental;
 

source/blender/makesrna/intern/rna_userdef.c

@@ -6442,6 +6442,10 @@ static void rna_def_userdef_experimental(BlenderRNA *brna)
   RNA_def_property_ui_text(prop,
                            "Named Attribute Nodes",
                            "Enable named attribute nodes in the geometry nodes add menu");
+
+  prop = RNA_def_property(srna, "enable_eevee_next", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "enable_eevee_next", 1);
+  RNA_def_property_ui_text(prop, "EEVEE Next", "Enable the new EEVEE codebase, requires restart");
 }
 
 static void rna_def_userdef_addon_collection(BlenderRNA *brna, PropertyRNA *cprop)

source/blender/render/RE_engine.h

@@ -253,6 +253,7 @@ void RE_engine_render_context_disable(struct RenderEngine *engine);
 /* Engine Types */
 
 void RE_engines_init(void);
+void RE_engines_init_experimental(void);
 void RE_engines_exit(void);
 void RE_engines_register(RenderEngineType *render_type);
 

source/blender/render/intern/engine.c

@@ -59,6 +59,11 @@ void RE_engines_init(void)
   DRW_engines_register();
 }
 
+void RE_engines_init_experimental()
+{
+  DRW_engines_register_experimental();
+}
+
 void RE_engines_exit(void)
 {
   RenderEngineType *type, *next;

source/creator/creator.c

@@ -488,6 +488,9 @@ int main(int argc,
 
   WM_init(C, argc, (const char **)argv);
 
+  /* Need to be after WM init so that userpref are loaded. */
+  RE_engines_init_experimental();
+
 #ifndef WITH_PYTHON
   printf(
       "\n* WARNING * - Blender compiled without Python!\n"