EEVEE-Next: Rework the material panel

- Adds the missing new RNA definitions
- Split settings panel into surface and volume
- Expose displacement and volume nodetree panels
- Rename `Cull Backfaces` to `Backface Culling`
  for consistency
- Rename `use_backface_culling_probe` to
  `lightprobe_volume_single_sided` for accuracy
  and avoiding confusion as it is not a real
  backface culling.
- Rename `Screen Space Refraction` to
  `Raytrace Refraction` for accuracy.

Motivation is to make it closer to cycles now
that EEVEE is compatible with more features.

Pull Request: https://projects.blender.org/blender/blender/pulls/113971

scripts/startup/bl_ui/properties_material.py

@@ -183,7 +183,7 @@ class EEVEE_MATERIAL_PT_volume(MaterialButtonsPanel, Panel):
     bl_translation_context = i18n_contexts.id_id
     bl_context = "material"
     bl_options = {'DEFAULT_CLOSED'}
-    COMPAT_ENGINES = {'BLENDER_EEVEE'}
+    COMPAT_ENGINES = {'BLENDER_EEVEE', 'BLENDER_EEVEE_NEXT'}
 
     @classmethod
     def poll(cls, context):
@@ -201,6 +201,29 @@ class EEVEE_MATERIAL_PT_volume(MaterialButtonsPanel, Panel):
         panel_node_draw(layout, mat.node_tree, 'OUTPUT_MATERIAL', "Volume")
 
 
+class EEVEE_MATERIAL_PT_displacement(MaterialButtonsPanel, Panel):
+    bl_label = "Displacement"
+    bl_translation_context = i18n_contexts.id_id
+    bl_context = "material"
+    bl_options = {'DEFAULT_CLOSED'}
+    COMPAT_ENGINES = {'BLENDER_EEVEE', 'BLENDER_EEVEE_NEXT'}
+
+    @classmethod
+    def poll(cls, context):
+        engine = context.engine
+        mat = context.material
+        return mat and mat.use_nodes and (engine in cls.COMPAT_ENGINES) and not mat.grease_pencil
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.use_property_split = True
+
+        mat = context.material
+
+        panel_node_draw(layout, mat.node_tree, 'OUTPUT_MATERIAL', "Displacement")
+
+
 def draw_material_settings(self, context):
     layout = self.layout
     layout.use_property_split = True
@@ -256,26 +279,54 @@ class EEVEE_NEXT_MATERIAL_PT_settings(MaterialButtonsPanel, Panel):
 
         mat = context.material
 
-        col = layout.column(heading="Cull Backfaces")
+        layout.prop(mat, "pass_index")
+
+
+class EEVEE_NEXT_MATERIAL_PT_settings_surface(MaterialButtonsPanel, Panel):
+    bl_label = "Surface"
+    bl_context = "material"
+    bl_parent_id = "EEVEE_NEXT_MATERIAL_PT_settings"
+    COMPAT_ENGINES = {'BLENDER_EEVEE_NEXT'}
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+        layout.use_property_decorate = False
+
+        mat = context.material
+
+        col = layout.column(heading="Backface Culling")
         col.prop(mat, "use_backface_culling", text="Camera")
         col.prop(mat, "use_backface_culling_shadow", text="Shadow")
-        col.prop(mat, "use_backface_culling_probe", text="Probe Capture")
 
-        layout.separator()
+        #TODO(fclem): Displacement option
+        #TODO(fclem): Transparent shadow option
 
-        layout.prop(mat, "blend_method")
+        col = layout.column()
-        layout.prop(mat, "shadow_method")
+        col.prop(mat, "surface_render_method", text="Render Method")
+        if mat.surface_render_method == 'BLENDED':
+            col.prop(mat, "show_transparent_back", text="Transparency Overlap")
+        elif mat.surface_render_method == 'DITHERED':
+            col.prop(mat, "use_screen_refraction", text="Raytraced Refraction")
 
-        row = layout.row()
+        col = layout.column(heading="Light Probe Volume")
-        row.active = ((mat.blend_method == 'CLIP') or (mat.shadow_method == 'CLIP'))
+        col.prop(mat, "lightprobe_volume_single_sided", text="Single Sided")
-        row.prop(mat, "alpha_threshold")
 
-        if mat.blend_method not in {'OPAQUE', 'CLIP', 'HASHED'}:
-            layout.prop(mat, "show_transparent_back")
 
-        layout.prop(mat, "use_screen_refraction")
+class EEVEE_NEXT_MATERIAL_PT_settings_volume(MaterialButtonsPanel, Panel):
-        layout.prop(mat, "volume_intersection_method")
+    bl_label = "Volume"
-        layout.prop(mat, "pass_index")
+    bl_context = "material"
+    bl_parent_id = "EEVEE_NEXT_MATERIAL_PT_settings"
+    COMPAT_ENGINES = {'BLENDER_EEVEE_NEXT'}
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+        layout.use_property_decorate = False
+
+        mat = context.material
+
+        layout.prop(mat, "volume_intersection_method", text="Intersection")
 
 
 class MATERIAL_PT_viewport(MaterialButtonsPanel, Panel):
@@ -345,8 +396,11 @@ classes = (
     EEVEE_MATERIAL_PT_context_material,
     EEVEE_MATERIAL_PT_surface,
     EEVEE_MATERIAL_PT_volume,
+    EEVEE_MATERIAL_PT_displacement,
     EEVEE_MATERIAL_PT_settings,
     EEVEE_NEXT_MATERIAL_PT_settings,
+    EEVEE_NEXT_MATERIAL_PT_settings_surface,
+    EEVEE_NEXT_MATERIAL_PT_settings_volume,
     MATERIAL_PT_lineart,
     MATERIAL_PT_viewport,
     EEVEE_MATERIAL_PT_viewport_settings,

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

@@ -1301,7 +1301,7 @@ PassMain::Sub *CapturePipeline::surface_material_add(::Material *blender_mat, GP
   GPUPass *gpupass = GPU_material_get_pass(gpumat);
   sub_pass.shader_set(GPU_pass_shader_get(gpupass));
   sub_pass.push_constant("is_double_sided",
-                         !(blender_mat->blend_flag & MA_BL_CULL_BACKFACE_PROBE));
+                         !(blender_mat->blend_flag & MA_BL_LIGHTPROBE_VOLUME_DOUBLE_SIDED));
   return &sub_pass;
 }
 

source/blender/makesdna/DNA_material_types.h

@@ -214,8 +214,8 @@ typedef struct Material {
   /* Transparency. */
   float alpha_threshold;
   float refract_depth;
-  char blend_method;
+  char blend_method; /* TODO(fclem): Deprecate once we remove legacy EEVEE. */
-  char blend_shadow;
+  char blend_shadow; /* TODO(fclem): Deprecate once we remove legacy EEVEE. */
   char blend_flag;
 
   /* Volume. */
@@ -358,7 +358,7 @@ enum {
   MA_BL_SS_REFRACTION = (1 << 1),
   MA_BL_CULL_BACKFACE = (1 << 2),
   MA_BL_TRANSLUCENCY = (1 << 3),
-  MA_BL_CULL_BACKFACE_PROBE = (1 << 4),
+  MA_BL_LIGHTPROBE_VOLUME_DOUBLE_SIDED = (1 << 4),
   MA_BL_CULL_BACKFACE_SHADOW = (1 << 5),
 };
 

source/blender/makesrna/intern/rna_material.cc

@@ -793,10 +793,12 @@ void RNA_def_material(BlenderRNA *brna)
        0,
        "Accurate",
        "Faces are considered as medium interface only when they have different consecutive "
-       "facing. Gives correct results as long as the max ray depth is not exceeded"},
+       "facing. Gives correct results as long as the max ray depth is not exceeded. Have "
+       "significant memory overhead compared to the fast method"},
       {0, nullptr, 0, nullptr, nullptr},
   };
 
+#  if 1 /* Delete this section once we remove old eevee. */
   static EnumPropertyItem prop_eevee_blend_items[] = {
       {MA_BM_SOLID, "OPAQUE", 0, "Opaque", "Render surface without transparency"},
       {MA_BM_CLIP,
@@ -832,6 +834,23 @@ void RNA_def_material(BlenderRNA *brna)
        "Use noise to dither the binary visibility and use filtering to reduce the noise"},
       {0, nullptr, 0, nullptr, nullptr},
   };
+#  endif
+
+  static EnumPropertyItem prop_eevee_surface_render_method_items[] = {
+      {MA_SURFACE_METHOD_DEFERRED,
+       "DITHERED",
+       0,
+       "Dithered",
+       "Allows for grayscale hashed transparency, and compatible with render passes and "
+       "raytracing. Also known as deferred rendering"},
+      {MA_SURFACE_METHOD_FORWARD,
+       "BLENDED",
+       0,
+       "Blended",
+       "Allows for colored transparency, but incompatible with render passes and raytracing. Also "
+       "known as forward rendering"},
+      {0, nullptr, 0, nullptr, nullptr},
+  };
 
   srna = RNA_def_struct(brna, "Material", "ID");
   RNA_def_struct_ui_text(
@@ -840,6 +859,14 @@ void RNA_def_material(BlenderRNA *brna)
       "Material data-block to define the appearance of geometric objects for rendering");
   RNA_def_struct_ui_icon(srna, ICON_MATERIAL_DATA);
 
+  prop = RNA_def_property(srna, "surface_render_method", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, prop_eevee_surface_render_method_items);
+  RNA_def_property_ui_text(prop,
+                           "Surface Render Method",
+                           "Controls the blending and the compatibility with certain features");
+  RNA_def_property_update(prop, 0, "rna_Material_draw_update");
+
+#  if 1 /* Delete this section once we remove old eevee. */
   /* Blending (only Eevee for now) */
   prop = RNA_def_property(srna, "blend_method", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(prop, prop_eevee_blend_items);
@@ -859,7 +886,9 @@ void RNA_def_material(BlenderRNA *brna)
                            "Clip Threshold",
                            "A pixel is rendered only if its alpha value is above this threshold");
   RNA_def_property_update(prop, 0, "rna_Material_draw_update");
+#  endif
 
+  /* TODO(fclem): Should be renamed to use_transparency_overlap. */
   prop = RNA_def_property(srna, "show_transparent_back", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_negative_sdna(prop, nullptr, "blend_flag", MA_BL_HIDE_BACKFACE);
   RNA_def_property_ui_text(prop,
@@ -876,21 +905,32 @@ void RNA_def_material(BlenderRNA *brna)
 
   prop = RNA_def_property(srna, "use_backface_culling_shadow", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, nullptr, "blend_flag", MA_BL_CULL_BACKFACE_SHADOW);
-  RNA_def_property_ui_text(prop, "Shadow Backface Culling", "Use back faces for casting shadows");
-  RNA_def_property_update(prop, 0, "rna_Material_draw_update");
-
-  prop = RNA_def_property(srna, "use_backface_culling_probe", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, nullptr, "blend_flag", MA_BL_CULL_BACKFACE_PROBE);
   RNA_def_property_ui_text(
-      prop, "Probe Capture Backface Culling", "Use back faces for probe captures");
+      prop, "Shadow Backface Culling", "Use back face culling when casting shadows");
   RNA_def_property_update(prop, 0, "rna_Material_draw_update");
 
+  prop = RNA_def_property(srna, "lightprobe_volume_single_sided", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_negative_sdna(
+      prop, nullptr, "blend_flag", MA_BL_LIGHTPROBE_VOLUME_DOUBLE_SIDED);
+  RNA_def_property_ui_text(
+      prop,
+      "Light Probe Volume Single Sided",
+      "Consider material single sided for light probe volume capture. "
+      "Additionnaly helps rejecting probes inside the object to avoid light leaks");
+  RNA_def_property_update(prop, 0, "rna_Material_draw_update");
+
+  /* TODO(fclem): Should be renamed to use_raytraced_refraction. */
   prop = RNA_def_property(srna, "use_screen_refraction", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, nullptr, "blend_flag", MA_BL_SS_REFRACTION);
   RNA_def_property_ui_text(
-      prop, "Screen Space Refraction", "Use raytraced screen space refractions");
+      prop,
+      "Raytrace Refraction",
+      "Use raytracing to determine refracted color instead of using only light probes. "
+      "This prevents the surface from contributing to the lighting of surfaces not using this "
+      "setting");
   RNA_def_property_update(prop, 0, "rna_Material_draw_update");
 
+#  if 1 /* Delete this section once we remove old eevee. */
   prop = RNA_def_property(srna, "use_sss_translucency", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, nullptr, "blend_flag", MA_BL_TRANSLUCENCY);
   RNA_def_property_ui_text(
@@ -905,6 +945,7 @@ void RNA_def_material(BlenderRNA *brna)
                            "Approximate the thickness of the object to compute two refraction "
                            "events (0 is disabled)");
   RNA_def_property_update(prop, 0, "rna_Material_draw_update");
+#  endif
 
   prop = RNA_def_property(srna, "volume_intersection_method", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(prop, prop_eevee_volume_isect_method_items);