Eevee: Material: Decouple transparent shadows from blend mode

This makes it easier to exclude a surface from casting shadows and can be
used to manipulate the shadows even for opaque surfaces.

Versionning ensure that old behavior is transfered to new rendering logic.

5 files changed, 37 insertions, 33 deletions

diff --git a/source/blender/blenkernel/BKE_blender_version.h b/source/blender/blenkernel/BKE_blender_version.h
index 66d0c3c4cac..9ae85725488 100644
--- a/source/blender/blenkernel/BKE_blender_version.h
+++ b/source/blender/blenkernel/BKE_blender_version.h
@@ -24,7 +24,7 @@
  * and keep comment above the defines.
  * Use STRINGIFY() rather than defining with quotes */
 #define BLENDER_VERSION         280
-#define BLENDER_SUBVERSION      52
+#define BLENDER_SUBVERSION      53
 /* Several breakages with 280, e.g. collections vs layers */
 #define BLENDER_MINVERSION      280
 #define BLENDER_MINSUBVERSION   0
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index f708984e51f..52e7c687694 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -142,6 +142,7 @@ void BKE_material_init(Material *ma)
 
 	ma->alpha_threshold = 0.5f;
 
+	ma->blend_shadow = MA_BS_SOLID;
 }
 
 Material *BKE_material_add(Main *bmain, const char *name)
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 522d036818d..960fb3b417c 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -2945,6 +2945,15 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
 		} FOREACH_NODETREE_END;
 	}
 
+	if (!MAIN_VERSION_ATLEAST(bmain, 280, 53)) {
+		for (Material *mat = bmain->materials.first; mat; mat = mat->id.next) {
+			/* Eevee: Keep material appearance consistent with previous behavior. */
+			if (!mat->use_nodes || !mat->nodetree || mat->blend_method == MA_BM_SOLID) {
+				mat->blend_shadow = MA_BS_SOLID;
+			}
+		}
+	}
+
 	{
 		/* Versioning code until next subversion bump goes here. */
 	}
diff --git a/source/blender/draw/engines/eevee/eevee_materials.c b/source/blender/draw/engines/eevee/eevee_materials.c
index ad49d3f8ae7..99a3c0c06cc 100644
--- a/source/blender/draw/engines/eevee/eevee_materials.c
+++ b/source/blender/draw/engines/eevee/eevee_materials.c
@@ -1624,34 +1624,28 @@ void EEVEE_materials_cache_populate(EEVEE_Data *vedata, EEVEE_ViewLayerData *sld
 					}
 
 					/* Shadow Pass */
-					if (ma->use_nodes && ma->nodetree && (ma->blend_method != MA_BM_SOLID)) {
-						struct GPUMaterial *gpumat;
-						switch (ma->blend_shadow) {
-							case MA_BS_SOLID:
-								EEVEE_lights_cache_shcaster_add(
-								        sldata, stl, mat_geom[i], ob);
-								*cast_shadow = true;
-								break;
-							case MA_BS_CLIP:
-								gpumat = EEVEE_material_mesh_depth_get(scene, ma, false, true);
-								EEVEE_lights_cache_shcaster_material_add(
-								        sldata, psl, gpumat, mat_geom[i], ob, &ma->alpha_threshold);
-								*cast_shadow = true;
-								break;
-							case MA_BS_HASHED:
-								gpumat = EEVEE_material_mesh_depth_get(scene, ma, true, true);
-								EEVEE_lights_cache_shcaster_material_add(
-								        sldata, psl, gpumat, mat_geom[i], ob, NULL);
-								*cast_shadow = true;
-								break;
-							case MA_BS_NONE:
-							default:
-								break;
-						}
-					}
-					else {
-						EEVEE_lights_cache_shcaster_add(sldata, stl, mat_geom[i], ob);
-						*cast_shadow = true;
+					struct GPUMaterial *gpumat;
+					switch (ma->blend_shadow) {
+						case MA_BS_SOLID:
+							EEVEE_lights_cache_shcaster_add(
+							        sldata, stl, mat_geom[i], ob);
+							*cast_shadow = true;
+							break;
+						case MA_BS_CLIP:
+							gpumat = EEVEE_material_mesh_depth_get(scene, ma, false, true);
+							EEVEE_lights_cache_shcaster_material_add(
+							        sldata, psl, gpumat, mat_geom[i], ob, &ma->alpha_threshold);
+							*cast_shadow = true;
+							break;
+						case MA_BS_HASHED:
+							gpumat = EEVEE_material_mesh_depth_get(scene, ma, true, true);
+							EEVEE_lights_cache_shcaster_material_add(
+							        sldata, psl, gpumat, mat_geom[i], ob, NULL);
+							*cast_shadow = true;
+							break;
+						case MA_BS_NONE:
+						default:
+							break;
 					}
 				}
 			}
diff --git a/source/blender/makesrna/intern/rna_material.c b/source/blender/makesrna/intern/rna_material.c
index 9e8604fb948..5445db78582 100644
--- a/source/blender/makesrna/intern/rna_material.c
+++ b/source/blender/makesrna/intern/rna_material.c
@@ -677,8 +677,8 @@ void RNA_def_material(BlenderRNA *brna)
 	static EnumPropertyItem prop_eevee_blend_shadow_items[] = {
 		{MA_BS_NONE, "NONE", 0, "None", "Material will cast no shadow"},
 		{MA_BS_SOLID, "OPAQUE", 0, "Opaque", "Material will cast shadows without transparency"},
-		{MA_BS_CLIP, "CLIP", 0, "Clip", "Use the alpha threshold to clip the visibility (binary visibility)"},
-		{MA_BS_HASHED, "HASHED", 0, "Hashed", "Use noise to dither the binary visibility and use filtering to reduce the noise"},
+		{MA_BS_CLIP, "CLIP", 0, "Alpha Clip", "Use the alpha threshold to clip the visibility (binary visibility)"},
+		{MA_BS_HASHED, "HASHED", 0, "Alpha Hashed", "Use noise to dither the binary visibility and use filtering to reduce the noise"},
 		{0, NULL, 0, NULL, NULL},
 	};
 
@@ -693,10 +693,10 @@ void RNA_def_material(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Blend Mode", "Blend Mode for Transparent Faces");
 	RNA_def_property_update(prop, 0, "rna_Material_draw_update");
 
-	prop = RNA_def_property(srna, "transparent_shadow_method", PROP_ENUM, PROP_NONE);
+	prop = RNA_def_property(srna, "shadow_method", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "blend_shadow");
 	RNA_def_property_enum_items(prop, prop_eevee_blend_shadow_items);
-	RNA_def_property_ui_text(prop, "Transparent Shadow", "Shadow mapping method for transparent material");
+	RNA_def_property_ui_text(prop, "Shadow Mode", "Shadow mapping method");
 	RNA_def_property_update(prop, 0, "rna_Material_draw_update");
 
 	prop = RNA_def_property(srna, "alpha_threshold", PROP_FLOAT, PROP_FACTOR);