Eevee: LightCache: Initial Implementation

This separate probe rendering from viewport rendering, making possible to
run the baking in another thread (non blocking and faster).

The baked lighting is saved in the blend file. Nothing needs to be
recomputed on load.

There is a few missing bits / bugs:
- Cache cannot be saved to disk as a separate file, it is saved in the DNA
  for now making file larger and memory usage higher.
- Auto update only cubemaps does update the grids (bug).
- Probes cannot be updated individually (considered as dynamic).
- Light Cache cannot be (re)generated during render.

1 files changed, 54 insertions, 3 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_lookdev.c b/source/blender/draw/engines/eevee/eevee_lookdev.c
index 01599177fa4..2e568d97c07 100644
--- a/source/blender/draw/engines/eevee/eevee_lookdev.c
+++ b/source/blender/draw/engines/eevee/eevee_lookdev.c
@@ -30,15 +30,31 @@
 #include "DNA_screen_types.h"
 #include "DNA_world_types.h"
 
+#include "DEG_depsgraph_query.h"
+
 #include "ED_screen.h"
 
 #include "eevee_private.h"
+#include "eevee_lightcache.h"
+
+static void eevee_lookdev_lightcache_delete(EEVEE_Data *vedata)
+{
+	EEVEE_StorageList *stl = vedata->stl;
+	EEVEE_TextureList *txl = vedata->txl;
+
+	MEM_SAFE_FREE(stl->lookdev_lightcache);
+	MEM_SAFE_FREE(stl->lookdev_grid_data);
+	MEM_SAFE_FREE(stl->lookdev_cube_data);
+	DRW_TEXTURE_FREE_SAFE(txl->lookdev_grid_tx);
+	DRW_TEXTURE_FREE_SAFE(txl->lookdev_cube_tx);
+}
 
 void EEVEE_lookdev_cache_init(
         EEVEE_Data *vedata, DRWShadingGroup **grp, GPUShader *shader, DRWPass *pass,
         World *world, EEVEE_LightProbesInfo *pinfo)
 {
 	EEVEE_StorageList *stl = vedata->stl;
+	EEVEE_TextureList *txl = vedata->txl;
 	const DRWContextState *draw_ctx = DRW_context_state_get();
 	View3D *v3d = draw_ctx->v3d;
 	if (LOOK_DEV_STUDIO_LIGHT_ENABLED(v3d)) {
@@ -47,6 +63,43 @@ void EEVEE_lookdev_cache_init(
 			struct Gwn_Batch *geom = DRW_cache_fullscreen_quad_get();
 			GPUTexture *tex = NULL;
 
+			/* If one of the component is missing we start from scratch. */
+			if ((stl->lookdev_grid_data == NULL) ||
+			    (stl->lookdev_cube_data == NULL) ||
+			    (txl->lookdev_grid_tx == NULL) ||
+			    (txl->lookdev_cube_tx == NULL))
+			{
+				eevee_lookdev_lightcache_delete(vedata);
+			}
+
+			if (stl->lookdev_lightcache == NULL) {
+				const Scene *scene_eval = DEG_get_evaluated_scene(draw_ctx->depsgraph);
+#if defined(IRRADIANCE_SH_L2)
+				int grid_res = 4;
+#elif defined(IRRADIANCE_CUBEMAP)
+				int grid_res = 8;
+#elif defined(IRRADIANCE_HL2)
+				int grid_res = 4;
+#endif
+				int cube_res = OCTAHEDRAL_SIZE_FROM_CUBESIZE(scene_eval->eevee.gi_cubemap_resolution);
+				int vis_res = scene_eval->eevee.gi_visibility_resolution;
+
+				stl->lookdev_lightcache = EEVEE_lightcache_create(1, 1, cube_res, vis_res, (int[3]){grid_res, grid_res, 1});
+
+				/* We do this to use a special light cache for lookdev.
+				 * This lightcache needs to be per viewport. But we need to
+				 * have correct freeing when the viewport is closed. So we
+				 * need to reference all textures to the txl and the memblocks
+				 * to the stl. */
+				stl->lookdev_grid_data = stl->lookdev_lightcache->grid_data;
+				stl->lookdev_cube_data = stl->lookdev_lightcache->cube_data;
+				stl->lookdev_cube_mips = stl->lookdev_lightcache->cube_mips;
+				txl->lookdev_grid_tx = stl->lookdev_lightcache->grid_tx.tex;
+				txl->lookdev_cube_tx = stl->lookdev_lightcache->cube_tx.tex;
+			}
+
+			stl->g_data->light_cache = stl->lookdev_lightcache;
+
 			*grp = DRW_shgroup_create(shader, pass);
 			axis_angle_to_mat3_single(stl->g_data->studiolight_matrix, 'Z', v3d->shading.studiolight_rot_z);
 			DRW_shgroup_uniform_mat3(*grp, "StudioLightMatrix", stl->g_data->studiolight_matrix);
@@ -77,11 +130,9 @@ void EEVEE_lookdev_cache_init(
 			    ((pinfo->studiolight_index != sl->index) ||
 			     (pinfo->studiolight_rot_z != v3d->shading.studiolight_rot_z)))
 			{
-				pinfo->update_world |= PROBE_UPDATE_ALL;
+				stl->lookdev_lightcache->flag |= LIGHTCACHE_UPDATE_WORLD;
 				pinfo->studiolight_index = sl->index;
 				pinfo->studiolight_rot_z = v3d->shading.studiolight_rot_z;
-				pinfo->prev_wo_sh_compiled = false;
-				pinfo->prev_world = NULL;
 			}
 		}
 	}