Fix T63283: Second subdivision modifier does not ignore crease

This is something where there is no single correct behavior,
sometimes it's needed to ignore the crease to make mesh more
smooth. But sometimes crease is to be considered after first
subdivision surface: for example, when adding extra subdivisions
for render-time displacement.

Made it an option whether modifier needs to take crease into
account or not.

Existing files should be openable in the 2.7 compatible way,
to re-create an old behavior the options is to be manually
disabled in the modifier settings.

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D4652

9 files changed, 54 insertions, 2 deletions

diff --git a/source/blender/blenkernel/BKE_blender_version.h b/source/blender/blenkernel/BKE_blender_version.h
index 9ae85725488..4c88410134c 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      53
+#define BLENDER_SUBVERSION      54
 /* Several breakages with 280, e.g. collections vs layers */
 #define BLENDER_MINVERSION      280
 #define BLENDER_MINSUBVERSION   0
diff --git a/source/blender/blenkernel/BKE_subdiv.h b/source/blender/blenkernel/BKE_subdiv.h
index 8c6b92e3638..f14a11005e7 100644
--- a/source/blender/blenkernel/BKE_subdiv.h
+++ b/source/blender/blenkernel/BKE_subdiv.h
@@ -58,6 +58,7 @@ typedef struct SubdivSettings {
 	bool is_simple;
 	bool is_adaptive;
 	int level;
+	bool use_creases;
 	eSubdivVtxBoundaryInterpolation vtx_boundary_interpolation;
 	eSubdivFVarLinearInterpolation fvar_linear_interpolation;
 } SubdivSettings;
diff --git a/source/blender/blenkernel/intern/multires_subdiv.c b/source/blender/blenkernel/intern/multires_subdiv.c
index 3d1a019f427..59229f28751 100644
--- a/source/blender/blenkernel/intern/multires_subdiv.c
+++ b/source/blender/blenkernel/intern/multires_subdiv.c
@@ -41,6 +41,7 @@ void BKE_multires_subdiv_settings_init(
 	settings->is_simple = (mmd->simple != 0);
 	settings->is_adaptive = true;
 	settings->level = settings->is_simple ? 1 : mmd->quality;
+	settings->use_creases = (mmd->flags & eMultiresModifierFlag_UseCrease);
 	settings->vtx_boundary_interpolation = SUBDIV_VTX_BOUNDARY_EDGE_ONLY;
 	settings->fvar_linear_interpolation =
 	        BKE_subdiv_fvar_interpolation_from_uv_smooth(mmd->uv_smooth);
diff --git a/source/blender/blenkernel/intern/subdiv_converter_mesh.c b/source/blender/blenkernel/intern/subdiv_converter_mesh.c
index 00a2436098e..eda6b522b85 100644
--- a/source/blender/blenkernel/intern/subdiv_converter_mesh.c
+++ b/source/blender/blenkernel/intern/subdiv_converter_mesh.c
@@ -168,6 +168,9 @@ static float get_edge_sharpness(const OpenSubdiv_Converter *converter,
 		return 10.0f;
 	}
 #endif
+	if (!storage->settings.use_creases) {
+		return 0.0f;
+	}
 	const int edge_index =
 	        storage->manifold_edge_index_reverse[manifold_edge_index];
 	const MEdge *medge = storage->mesh->medge;
@@ -190,9 +193,13 @@ static bool is_infinite_sharp_vertex(const OpenSubdiv_Converter *converter,
 	                            vertex_index);
 }
 
-static float get_vertex_sharpness(const OpenSubdiv_Converter *UNUSED(converter),
+static float get_vertex_sharpness(const OpenSubdiv_Converter *converter,
                                   int UNUSED(manifold_vertex_index))
 {
+	ConverterStorage *storage = converter->user_data;
+	if (!storage->settings.use_creases) {
+		return 0.0f;
+	}
 	return 0.0f;
 }
 
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 5c0ff1af7b2..25ada2fd13e 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -2967,6 +2967,34 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
 		}
 	}
 
+	if (!MAIN_VERSION_ATLEAST(bmain, 280, 54)) {
+		for (Object *ob = bmain->objects.first; ob; ob = ob->id.next) {
+			bool is_first_subdiv = true;
+			for (ModifierData *md = ob->modifiers.first; md; md = md->next) {
+				if (md->type == eModifierType_Subsurf) {
+					SubsurfModifierData *smd = (SubsurfModifierData *)md;
+					if (is_first_subdiv) {
+						smd->flags |= eSubsurfModifierFlag_UseCrease;
+					}
+					else {
+						smd->flags &= ~eSubsurfModifierFlag_UseCrease;
+					}
+					is_first_subdiv = false;
+				}
+				else if (md->type == eModifierType_Multires) {
+					MultiresModifierData *mmd = (MultiresModifierData *)md;
+					if (is_first_subdiv) {
+						mmd->flags |= eMultiresModifierFlag_UseCrease;
+					}
+					else {
+						mmd->flags &= ~eMultiresModifierFlag_UseCrease;
+					}
+					is_first_subdiv = false;
+				}
+			}
+		}
+	}
+
 	{
 		/* Versioning code until next subversion bump goes here. */
 
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index 14f8a63a359..fcdfb4fcf44 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -144,6 +144,7 @@ typedef enum {
 	eSubsurfModifierFlag_ControlEdges = (1 << 2),
 	/* DEPRECATED, ONLY USED FOR DO-VERSIONS */
 	eSubsurfModifierFlag_SubsurfUv_DEPRECATED    = (1 << 3),
+	eSubsurfModifierFlag_UseCrease   =  (1 << 4),
 } SubsurfModifierFlag;
 
 typedef enum {
@@ -960,6 +961,7 @@ typedef enum {
 	eMultiresModifierFlag_ControlEdges = (1 << 0),
 	/* DEPRECATED, only used for versioning. */
 	eMultiresModifierFlag_PlainUv_DEPRECATED      = (1 << 1),
+	eMultiresModifierFlag_UseCrease    =  (1 << 2),
 } MultiresModifierFlag;
 
 typedef struct FluidsimModifierData {
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 6dca81415f3..18ab5565d22 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -1278,6 +1278,11 @@ static void rna_def_modifier_subsurf(BlenderRNA *brna)
 	RNA_def_property_boolean_sdna(prop, NULL, "flags", eSubsurfModifierFlag_ControlEdges);
 	RNA_def_property_ui_text(prop, "Optimal Display", "Skip drawing/rendering of interior subdivided edges");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
+	prop = RNA_def_property(srna, "use_creases", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flags", eSubsurfModifierFlag_UseCrease);
+	RNA_def_property_ui_text(prop, "Use Creases", "Use mesh edge crease information to sharpen edges");
+	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 }
 
 static void rna_def_modifier_generic_map_info(StructRNA *srna)
@@ -1423,6 +1428,11 @@ static void rna_def_modifier_multires(BlenderRNA *brna)
 	RNA_def_property_boolean_sdna(prop, NULL, "flags", eMultiresModifierFlag_ControlEdges);
 	RNA_def_property_ui_text(prop, "Optimal Display", "Skip drawing/rendering of interior subdivided edges");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
+	prop = RNA_def_property(srna, "use_creases", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flags", eMultiresModifierFlag_UseCrease);
+	RNA_def_property_ui_text(prop, "Use Creases", "Use mesh edge crease information to sharpen edges");
+	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 }
 
 static void rna_def_modifier_lattice(BlenderRNA *brna)
diff --git a/source/blender/modifiers/intern/MOD_multires.c b/source/blender/modifiers/intern/MOD_multires.c
index af17bd7d53c..a8760d05834 100644
--- a/source/blender/modifiers/intern/MOD_multires.c
+++ b/source/blender/modifiers/intern/MOD_multires.c
@@ -61,6 +61,7 @@ static void initData(ModifierData *md)
 	mmd->totlvl = 0;
 	mmd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
 	mmd->quality = 3;
+	mmd->flags |= eMultiresModifierFlag_UseCrease;
 }
 
 static void copyData(const ModifierData *md_src, ModifierData *md_dst, const int flag)
diff --git a/source/blender/modifiers/intern/MOD_subsurf.c b/source/blender/modifiers/intern/MOD_subsurf.c
index 40c9e5c3b1b..74bf6b7e976 100644
--- a/source/blender/modifiers/intern/MOD_subsurf.c
+++ b/source/blender/modifiers/intern/MOD_subsurf.c
@@ -59,6 +59,7 @@ static void initData(ModifierData *md)
 	smd->renderLevels = 2;
 	smd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
 	smd->quality = 3;
+	smd->flags |= eSubsurfModifierFlag_UseCrease;
 }
 
 static void copyData(const ModifierData *md, ModifierData *target, const int flag)
@@ -126,6 +127,7 @@ static void subdiv_settings_init(SubdivSettings *settings,
 	settings->is_simple = (smd->subdivType == SUBSURF_TYPE_SIMPLE);
 	settings->is_adaptive = true;
 	settings->level = settings->is_simple ? 1 : smd->quality;
+	settings->use_creases = (smd->flags & eSubsurfModifierFlag_UseCrease);
 	settings->vtx_boundary_interpolation = SUBDIV_VTX_BOUNDARY_EDGE_ONLY;
 	settings->fvar_linear_interpolation =
 	        BKE_subdiv_fvar_interpolation_from_uv_smooth(smd->uv_smooth);