EEVEE: Lookdev: Add support for partially blurred background

This is using the GGX probe as background. This has the drawback of
having the resolution choosed in the indirect lighting setting.
The blurring is not really high-quality.

The pros is that it has a simple implementation and is fast to evaluate.

This patch also fades the background alpha to make overlay engine draw the
default background color in the correct color space. Removing one colorspace
hack.

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D6895

6 files changed, 73 insertions, 45 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_lightprobes.c b/source/blender/draw/engines/eevee/eevee_lightprobes.c
index 52902d84b7e..5e6c11833d3 100644
--- a/source/blender/draw/engines/eevee/eevee_lightprobes.c
+++ b/source/blender/draw/engines/eevee/eevee_lightprobes.c
@@ -343,7 +343,7 @@ void EEVEE_lightprobes_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedat
     const float *col = G_draw.block.colorBackground;
 
     /* LookDev */
-    EEVEE_lookdev_cache_init(vedata, &grp, psl->probe_background, 1.0f, wo, pinfo);
+    EEVEE_lookdev_cache_init(vedata, sldata, &grp, psl->probe_background, wo, pinfo);
     /* END */
     if (!grp && wo) {
       col = &wo->horr;
diff --git a/source/blender/draw/engines/eevee/eevee_lookdev.c b/source/blender/draw/engines/eevee/eevee_lookdev.c
index 55a35087684..e89ef7142ee 100644
--- a/source/blender/draw/engines/eevee/eevee_lookdev.c
+++ b/source/blender/draw/engines/eevee/eevee_lookdev.c
@@ -57,9 +57,9 @@ static void eevee_lookdev_lightcache_delete(EEVEE_Data *vedata)
 }
 
 void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
-                              DRWShadingGroup **grp,
+                              EEVEE_ViewLayerData *sldata,
+                              DRWShadingGroup **r_grp,
                               DRWPass *pass,
-                              float background_alpha,
                               World *UNUSED(world),
                               EEVEE_LightProbesInfo *pinfo)
 {
@@ -69,8 +69,11 @@ void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
   EEVEE_PrivateData *g_data = stl->g_data;
   const DRWContextState *draw_ctx = DRW_context_state_get();
   View3D *v3d = draw_ctx->v3d;
+  View3DShading *shading = &v3d->shading;
   Scene *scene = draw_ctx->scene;
 
+  const bool probe_render = pinfo != NULL;
+
   effects->lookdev_view = NULL;
 
   if (LOOK_DEV_OVERLAY_ENABLED(v3d)) {
@@ -95,12 +98,11 @@ void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
   }
 
   if (LOOK_DEV_STUDIO_LIGHT_ENABLED(v3d)) {
-    StudioLight *sl = BKE_studiolight_find(v3d->shading.lookdev_light,
+    StudioLight *sl = BKE_studiolight_find(shading->lookdev_light,
                                            STUDIOLIGHT_ORIENTATIONS_MATERIAL_MODE);
     if (sl && (sl->flag & STUDIOLIGHT_TYPE_WORLD)) {
-      GPUShader *shader = EEVEE_shaders_default_studiolight_sh_get();
-      struct GPUBatch *geom = DRW_cache_fullscreen_quad_get();
-      GPUTexture *tex = NULL;
+      GPUShader *shader = probe_render ? EEVEE_shaders_default_studiolight_sh_get() :
+                                         EEVEE_shaders_background_studiolight_sh_get();
 
       /* If one of the component is missing we start from scratch. */
       if ((stl->lookdev_grid_data == NULL) || (stl->lookdev_cube_data == NULL) ||
@@ -138,49 +140,45 @@ void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
         txl->lookdev_cube_tx = stl->lookdev_lightcache->cube_tx.tex;
       }
 
-      stl->g_data->light_cache = stl->lookdev_lightcache;
-
-      static float background_color[4];
-      UI_GetThemeColor4fv(TH_BACK, background_color);
-      /* XXX: Really quick conversion to avoid washed out background.
-       * Needs to be addressed properly (color managed using ocio). */
-      srgb_to_linearrgb_v4(background_color, background_color);
-
-      *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);
-      DRW_shgroup_uniform_float_copy(*grp, "backgroundAlpha", background_alpha);
-      DRW_shgroup_uniform_float(
-          *grp, "studioLightIntensity", &v3d->shading.studiolight_intensity, 1);
-
-      DRW_shgroup_uniform_vec3(*grp, "color", background_color, 1);
-      DRW_shgroup_call(*grp, geom, NULL);
-      if (!pinfo) {
+      g_data->light_cache = stl->lookdev_lightcache;
+
+      DRWShadingGroup *grp = *r_grp = DRW_shgroup_create(shader, pass);
+      axis_angle_to_mat3_single(g_data->studiolight_matrix, 'Z', shading->studiolight_rot_z);
+      DRW_shgroup_uniform_mat3(grp, "StudioLightMatrix", g_data->studiolight_matrix);
+
+      if (probe_render) {
+        DRW_shgroup_uniform_float_copy(
+            grp, "studioLightIntensity", shading->studiolight_intensity);
+        BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_EQUIRECT_RADIANCE_GPUTEXTURE);
+        DRW_shgroup_uniform_texture(grp, "image", sl->equirect_radiance_gputexture);
         /* Do not fadeout when doing probe rendering, only when drawing the background */
-        DRW_shgroup_uniform_float(
-            *grp, "studioLightBackground", &v3d->shading.studiolight_background, 1);
-        BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_EQUIRECT_IRRADIANCE_GPUTEXTURE);
-        tex = sl->equirect_irradiance_gputexture;
+        DRW_shgroup_uniform_float_copy(grp, "backgroundAlpha", 1.0f);
       }
       else {
-        DRW_shgroup_uniform_float_copy(*grp, "studioLightBackground", 1.0f);
-        BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_EQUIRECT_RADIANCE_GPUTEXTURE);
-        tex = sl->equirect_radiance_gputexture;
+        float background_alpha = g_data->background_alpha * shading->studiolight_background;
+        float studiolight_blur = powf(shading->studiolight_blur, 2.5f);
+        DRW_shgroup_uniform_float_copy(grp, "backgroundAlpha", background_alpha);
+        DRW_shgroup_uniform_float_copy(grp, "studioLightBlur", studiolight_blur);
+        DRW_shgroup_uniform_texture(grp, "probeCubes", txl->lookdev_cube_tx);
+        DRW_shgroup_uniform_block(grp, "probe_block", sldata->probe_ubo);
+        DRW_shgroup_uniform_block(grp, "grid_block", sldata->grid_ubo);
+        DRW_shgroup_uniform_block(grp, "planar_block", sldata->planar_ubo);
+        DRW_shgroup_uniform_block(grp, "common_block", sldata->common_ubo);
       }
-      DRW_shgroup_uniform_texture(*grp, "image", tex);
+
+      DRW_shgroup_call(grp, DRW_cache_fullscreen_quad_get(), NULL);
 
       /* Do we need to recalc the lightprobes? */
       if (g_data->studiolight_index != sl->index ||
-          g_data->studiolight_rot_z != v3d->shading.studiolight_rot_z ||
-          g_data->studiolight_intensity != v3d->shading.studiolight_intensity ||
+          g_data->studiolight_rot_z != shading->studiolight_rot_z ||
+          g_data->studiolight_intensity != shading->studiolight_intensity ||
           g_data->studiolight_cubemap_res != scene->eevee.gi_cubemap_resolution ||
           g_data->studiolight_glossy_clamp != scene->eevee.gi_glossy_clamp ||
           g_data->studiolight_filter_quality != scene->eevee.gi_filter_quality) {
         stl->lookdev_lightcache->flag |= LIGHTCACHE_UPDATE_WORLD;
         g_data->studiolight_index = sl->index;
-        g_data->studiolight_rot_z = v3d->shading.studiolight_rot_z;
-        g_data->studiolight_intensity = v3d->shading.studiolight_intensity;
+        g_data->studiolight_rot_z = shading->studiolight_rot_z;
+        g_data->studiolight_intensity = shading->studiolight_intensity;
         g_data->studiolight_cubemap_res = scene->eevee.gi_cubemap_resolution;
         g_data->studiolight_glossy_clamp = scene->eevee.gi_glossy_clamp;
         g_data->studiolight_filter_quality = scene->eevee.gi_filter_quality;
diff --git a/source/blender/draw/engines/eevee/eevee_materials.c b/source/blender/draw/engines/eevee/eevee_materials.c
index 3c793ca0693..0c9efeb0a16 100644
--- a/source/blender/draw/engines/eevee/eevee_materials.c
+++ b/source/blender/draw/engines/eevee/eevee_materials.c
@@ -1158,8 +1158,7 @@ void EEVEE_materials_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata)
 
     const float *col = G_draw.block.colorBackground;
 
-    EEVEE_lookdev_cache_init(
-        vedata, &grp, psl->background_pass, stl->g_data->background_alpha, wo, NULL);
+    EEVEE_lookdev_cache_init(vedata, sldata, &grp, psl->background_pass, wo, NULL);
 
     if (!grp && wo) {
       col = &wo->horr;
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index dfe3dc5a538..a2ed0a16d89 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -987,6 +987,7 @@ struct GPUShader *EEVEE_shaders_probe_filter_visibility_sh_get(void);
 struct GPUShader *EEVEE_shaders_probe_grid_fill_sh_get(void);
 struct GPUShader *EEVEE_shaders_probe_planar_downsample_sh_get(void);
 struct GPUShader *EEVEE_shaders_default_studiolight_sh_get(void);
+struct GPUShader *EEVEE_shaders_background_studiolight_sh_get(void);
 struct GPUShader *EEVEE_shaders_probe_cube_display_sh_get(void);
 struct GPUShader *EEVEE_shaders_probe_grid_display_sh_get(void);
 struct GPUShader *EEVEE_shaders_probe_planar_display_sh_get(void);
@@ -1196,9 +1197,9 @@ void EEVEE_render_update_passes(struct RenderEngine *engine,
 
 /** eevee_lookdev.c */
 void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
+                              EEVEE_ViewLayerData *sldata,
                               DRWShadingGroup **grp,
                               DRWPass *pass,
-                              float background_alpha,
                               struct World *world,
                               EEVEE_LightProbesInfo *pinfo);
 void EEVEE_lookdev_draw(EEVEE_Data *vedata);
diff --git a/source/blender/draw/engines/eevee/eevee_shaders.c b/source/blender/draw/engines/eevee/eevee_shaders.c
index 34a3e723161..2d91e4bb4bd 100644
--- a/source/blender/draw/engines/eevee/eevee_shaders.c
+++ b/source/blender/draw/engines/eevee/eevee_shaders.c
@@ -44,6 +44,7 @@ static struct {
   /* Probes */
   struct GPUShader *probe_default_sh;
   struct GPUShader *probe_default_studiolight_sh;
+  struct GPUShader *probe_background_studiolight_sh;
   struct GPUShader *probe_grid_display_sh;
   struct GPUShader *probe_cube_display_sh;
   struct GPUShader *probe_planar_display_sh;
@@ -191,6 +192,27 @@ GPUShader *EEVEE_shaders_default_studiolight_sh_get(void)
   return e_data.probe_default_studiolight_sh;
 }
 
+GPUShader *EEVEE_shaders_background_studiolight_sh_get(void)
+{
+  if (e_data.probe_background_studiolight_sh == NULL) {
+    char *frag_str = BLI_string_joinN(datatoc_octahedron_lib_glsl,
+                                      datatoc_common_uniforms_lib_glsl,
+                                      datatoc_bsdf_common_lib_glsl,
+                                      datatoc_lightprobe_lib_glsl,
+                                      datatoc_default_world_frag_glsl);
+
+    e_data.probe_background_studiolight_sh = DRW_shader_create_with_lib(
+        datatoc_background_vert_glsl,
+        NULL,
+        frag_str,
+        datatoc_common_view_lib_glsl,
+        "#define LOOKDEV_BG\n" SHADER_DEFINES);
+
+    MEM_freeN(frag_str);
+  }
+  return e_data.probe_background_studiolight_sh;
+}
+
 GPUShader *EEVEE_shaders_probe_cube_display_sh_get(void)
 {
   if (e_data.probe_cube_display_sh == NULL) {
@@ -299,6 +321,7 @@ void EEVEE_shaders_free(void)
   DRW_SHADER_FREE_SAFE(e_data.probe_grid_fill_sh);
   DRW_SHADER_FREE_SAFE(e_data.probe_planar_downsample_sh);
   DRW_SHADER_FREE_SAFE(e_data.probe_default_studiolight_sh);
+  DRW_SHADER_FREE_SAFE(e_data.probe_background_studiolight_sh);
   DRW_SHADER_FREE_SAFE(e_data.probe_grid_display_sh);
   DRW_SHADER_FREE_SAFE(e_data.probe_cube_display_sh);
   DRW_SHADER_FREE_SAFE(e_data.probe_planar_display_sh);
diff --git a/source/blender/draw/engines/eevee/shaders/default_world_frag.glsl b/source/blender/draw/engines/eevee/shaders/default_world_frag.glsl
index 41e103609f3..1faa02fd354 100644
--- a/source/blender/draw/engines/eevee/shaders/default_world_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/default_world_frag.glsl
@@ -4,11 +4,12 @@ uniform vec3 color;
 
 out vec4 FragColor;
 
-#ifdef LOOKDEV
+#if defined(LOOKDEV_BG) || defined(LOOKDEV)
+
 uniform mat3 StudioLightMatrix;
 uniform sampler2D image;
-uniform float studioLightBackground = 1.0;
 uniform float studioLightIntensity = 1.0;
+uniform float studioLightBlur = 0.0;
 in vec3 viewPosition;
 
 #  define M_PI 3.14159265358979323846
@@ -49,11 +50,17 @@ vec4 node_tex_environment_equirectangular(vec3 co, sampler2D ima)
 void main()
 {
   vec3 background_color;
-#ifdef LOOKDEV
+
+#if defined(LOOKDEV_BG)
+  vec3 worldvec = background_transform_to_world(viewPosition);
+  background_color = probe_evaluate_world_spec(worldvec, studioLightBlur).rgb;
+  background_color *= studioLightIntensity;
+
+#elif defined(LOOKDEV)
   vec3 worldvec = background_transform_to_world(viewPosition);
   background_color = node_tex_environment_equirectangular(StudioLightMatrix * worldvec, image).rgb;
   background_color *= studioLightIntensity;
-  background_color = mix(color, background_color, studioLightBackground);
+
 #else
   background_color = color;
 #endif