EEVEE-Next: Add tracing options for diffuse rays

Also fixes diffuse surface always tracing
even when tracing is off.

scripts/startup/bl_ui/properties_render.py

@@ -652,7 +652,7 @@ class RENDER_PT_eevee_next_raytracing_reflection(EeveeRaytracingOptionsPanel):
     def draw_header(self, context):
         layout = self.layout
         if context.scene.eevee.ray_split_settings == 'UNIFIED':
-            layout.label(text="Reflection & Refraction")
+            layout.label(text="Reflection & Refraction & Diffuse")
         else:
             layout.label(text="Reflection")
 
@@ -706,6 +706,35 @@ class RENDER_PT_eevee_next_denoise_refraction(EeveeRaytracingDenoisePanel):
         self.draw_internal(context.scene.eevee.refraction_options)
 
 
+class RENDER_PT_eevee_next_raytracing_diffuse(EeveeRaytracingOptionsPanel):
+    bl_label = "Diffuse"
+    bl_parent_id = "RENDER_PT_eevee_next_raytracing"
+
+    @classmethod
+    def poll(cls, context):
+        return (context.scene.eevee.ray_split_settings == 'SPLIT')
+
+    def draw(self, context):
+        self.draw_internal(context, context.scene.eevee.diffuse_options)
+
+
+class RENDER_PT_eevee_next_screen_trace_diffuse(EeveeRaytracingScreenOption):
+    bl_parent_id = "RENDER_PT_eevee_next_raytracing_diffuse"
+
+    def draw(self, context):
+        self.draw_internal(context.scene.eevee.diffuse_options)
+
+
+class RENDER_PT_eevee_next_denoise_diffuse(EeveeRaytracingDenoisePanel):
+    bl_parent_id = "RENDER_PT_eevee_next_raytracing_diffuse"
+
+    def draw_header(self, context):
+        self.draw_header_internal(context.scene.eevee.diffuse_options)
+
+    def draw(self, context):
+        self.draw_internal(context.scene.eevee.diffuse_options)
+
+
 class RENDER_PT_eevee_shadows(RenderButtonsPanel, Panel):
     bl_label = "Shadows"
     bl_options = {'DEFAULT_CLOSED'}
@@ -1240,10 +1269,13 @@ classes = (
     RENDER_PT_eevee_next_raytracing,
     RENDER_PT_eevee_next_raytracing_reflection,
     RENDER_PT_eevee_next_raytracing_refraction,
+    RENDER_PT_eevee_next_raytracing_diffuse,
     RENDER_PT_eevee_next_screen_trace_reflection,
     RENDER_PT_eevee_next_screen_trace_refraction,
+    RENDER_PT_eevee_next_screen_trace_diffuse,
     RENDER_PT_eevee_next_denoise_reflection,
     RENDER_PT_eevee_next_denoise_refraction,
+    RENDER_PT_eevee_next_denoise_diffuse,
     RENDER_PT_eevee_motion_blur,
     RENDER_PT_eevee_next_motion_blur,
     RENDER_PT_motion_blur_curve,

source/blender/blenloader/intern/versioning_400.cc

@@ -1510,5 +1510,12 @@ void blo_do_versions_400(FileData *fd, Library * /*lib*/, Main *bmain)
         light->shadow_trace_distance = default_light.shadow_trace_distance;
       }
     }
+
+    if (!DNA_struct_member_exists(fd->filesdna, "SceneEEVEE", "RaytraceEEVEE", "diffuse_options"))
+    {
+      LISTBASE_FOREACH (Scene *, scene, &bmain->scenes) {
+        scene->eevee.diffuse_options = scene->eevee.reflection_options;
+      }
+    }
   }
 }

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

@@ -30,10 +30,12 @@ void RayTraceModule::init()
 
   reflection_options_ = sce_eevee.reflection_options;
   refraction_options_ = sce_eevee.refraction_options;
+  diffuse_options_ = sce_eevee.diffuse_options;
   tracing_method_ = RaytraceEEVEE_Method(sce_eevee.ray_tracing_method);
 
   if (sce_eevee.ray_split_settings == 0) {
     refraction_options_ = reflection_options_;
+    diffuse_options_ = reflection_options_;
   }
 }
 
@@ -218,9 +220,9 @@ RayTraceResult RayTraceModule::trace(RayTraceBuffer &rt_buffer,
   RayTraceBuffer::DenoiseBuffer *denoise_buf = nullptr;
 
   if (raytrace_closure == CLOSURE_DIFFUSE) {
-    options = reflection_options_;
+    options = diffuse_options_;
     generate_ray_ps = &generate_diffuse_ps_;
-    trace_ray_ps = force_no_tracing ? &trace_diffuse_ps_ : &trace_diffuse_ps_;
+    trace_ray_ps = force_no_tracing ? &trace_fallback_ps_ : &trace_diffuse_ps_;
     denoise_spatial_ps = &denoise_spatial_diffuse_ps_;
     denoise_bilateral_ps = &denoise_bilateral_diffuse_ps_;
     denoise_buf = &rt_buffer.diffuse;

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

@@ -164,6 +164,7 @@ class RayTraceModule {
   /** Copy of the scene options to avoid changing parameters during motion blur. */
   RaytraceEEVEE reflection_options_;
   RaytraceEEVEE refraction_options_;
+  RaytraceEEVEE diffuse_options_;
 
   RaytraceEEVEE_Method tracing_method_ = RAYTRACE_EEVEE_METHOD_NONE;
 

source/blender/draw/engines/eevee_next/shaders/eevee_ray_generate_lib.glsl

@@ -18,7 +18,7 @@
 /* Could maybe become parameters. */
 #define RAY_BIAS_REFLECTION 0.02
 #define RAY_BIAS_REFRACTION 0.02
-#define RAY_BIAS_DIFFUSE 0.02
+#define RAY_BIAS_DIFFUSE 0.05
 
 /* Returns view-space ray. */
 vec3 ray_generate_direction(vec2 noise, ClosureReflection reflection, vec3 V, out float pdf)
@@ -68,6 +68,5 @@ vec3 ray_generate_direction(vec2 noise, ClosureDiffuse diffuse, vec3 V, out floa
 
   vec3 T, B, N = diffuse.N;
   make_orthonormal_basis(N, T, B);
-
   return sample_cosine_hemisphere(Xi, N, T, B, pdf);
 }

source/blender/makesdna/DNA_scene_defaults.h

@@ -238,6 +238,7 @@
  \
     .reflection_options = _DNA_DEFAULT_RaytraceEEVEE, \
     .refraction_options = _DNA_DEFAULT_RaytraceEEVEE, \
+    .diffuse_options = _DNA_DEFAULT_RaytraceEEVEE, \
  \
     .light_cache_data = NULL, \
     .light_threshold = 0.01f, \

source/blender/makesdna/DNA_scene_types.h

@@ -1895,6 +1895,7 @@ typedef struct SceneEEVEE {
 
   struct RaytraceEEVEE reflection_options;
   struct RaytraceEEVEE refraction_options;
+  struct RaytraceEEVEE diffuse_options;
 
   struct LightCache *light_cache DNA_DEPRECATED;
   struct LightCache *light_cache_data;

source/blender/makesrna/intern/rna_scene.cc

@@ -8120,6 +8120,11 @@ static void rna_def_scene_eevee(BlenderRNA *brna)
   RNA_def_property_struct_type(prop, "RaytraceEEVEE");
   RNA_def_property_ui_text(
       prop, "Refraction Trace Options", "EEVEE settings for tracing refractions");
+
+  prop = RNA_def_property(srna, "diffuse_options", PROP_POINTER, PROP_NONE);
+  RNA_def_property_struct_type(prop, "RaytraceEEVEE");
+  RNA_def_property_ui_text(
+      prop, "Diffuse Trace Options", "EEVEE settings for tracing diffuse reflections");
 }
 
 static void rna_def_scene_gpencil(BlenderRNA *brna)