Subsurf: Make uv boundaries easily extendible

This replaces old single toggle option to subdivide UVs with
an enum which can have more options. The usecase for this is
to be compatible with other software. But we also might choose
different subdivision type as default in the future.

DNA and underlying code supports all possible options, but
only the ones which are compatible with old subdivision code
are currently exposes.

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D3575

9 files changed, 94 insertions, 12 deletions

diff --git a/source/blender/blenkernel/BKE_subdiv.h b/source/blender/blenkernel/BKE_subdiv.h
index d81047563a7..03d765a154f 100644
--- a/source/blender/blenkernel/BKE_subdiv.h
+++ b/source/blender/blenkernel/BKE_subdiv.h
@@ -42,6 +42,8 @@ struct OpenSubdiv_TopologyRefiner;
 typedef enum {
 	SUBDIV_FVAR_LINEAR_INTERPOLATION_NONE,
 	SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY,
+	SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_AND_JUNCTIONS,
+	SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_JUNCTIONS_AND_CONCAVE,
 	SUBDIV_FVAR_LINEAR_INTERPOLATION_BOUNDARIES,
 	SUBDIV_FVAR_LINEAR_INTERPOLATION_ALL,
 } eSubdivFVarLinearInterpolation;
diff --git a/source/blender/blenkernel/intern/multires.c b/source/blender/blenkernel/intern/multires.c
index 331b3797739..d35d363428b 100644
--- a/source/blender/blenkernel/intern/multires.c
+++ b/source/blender/blenkernel/intern/multires.c
@@ -729,7 +729,10 @@ static DerivedMesh *subsurf_dm_create_local(
 
 	smd.levels = smd.renderLevels = lvl;
 	if (!is_plain_uv) {
-		smd.flags |= eSubsurfModifierFlag_SubsurfUv;
+		smd.uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
+	}
+	else {
+		smd.uv_smooth = SUBSURF_UV_SMOOTH_NONE;
 	}
 	if (is_simple) {
 		smd.subdivType = ME_SIMPLE_SUBSURF;
diff --git a/source/blender/blenkernel/intern/subdiv_converter.c b/source/blender/blenkernel/intern/subdiv_converter.c
index 0ef32200bd3..5cad2f3e4cd 100644
--- a/source/blender/blenkernel/intern/subdiv_converter.c
+++ b/source/blender/blenkernel/intern/subdiv_converter.c
@@ -44,6 +44,10 @@ BKE_subdiv_converter_fvar_linear_from_settings(const SubdivSettings *settings)
 			return OSD_FVAR_LINEAR_INTERPOLATION_NONE;
 		case SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY:
 			return OSD_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY;
+		case SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_AND_JUNCTIONS:
+			return OSD_FVAR_LINEAR_INTERPOLATION_CORNERS_PLUS1;
+		case SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_JUNCTIONS_AND_CONCAVE:
+			return OSD_FVAR_LINEAR_INTERPOLATION_CORNERS_PLUS2;
 		case SUBDIV_FVAR_LINEAR_INTERPOLATION_BOUNDARIES:
 			return OSD_FVAR_LINEAR_INTERPOLATION_BOUNDARIES;
 		case SUBDIV_FVAR_LINEAR_INTERPOLATION_ALL:
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index cead75ae659..9fda7f585b4 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -2927,7 +2927,7 @@ struct DerivedMesh *subsurf_make_derived_from_derived(
 {
 	int useSimple = (smd->subdivType == ME_SIMPLE_SUBSURF) ? CCG_SIMPLE_SUBDIV : 0;
 	CCGFlags useAging = (smd->flags & eSubsurfModifierFlag_DebugIncr) ? CCG_USE_AGING : 0;
-	int useSubsurfUv = smd->flags & eSubsurfModifierFlag_SubsurfUv;
+	int useSubsurfUv = (smd->uv_smooth != SUBSURF_UV_SMOOTH_NONE);
 	int drawInteriorEdges = !(smd->flags & eSubsurfModifierFlag_ControlEdges);
 	CCGDerivedMesh *result;
 	bool use_gpu_backend = subsurf_use_gpu_backend(flags);
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index aed1fd8b416..f9bf1d9baa6 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -48,6 +48,7 @@
 #include "DNA_lightprobe_types.h"
 #include "DNA_material_types.h"
 #include "DNA_mesh_types.h"
+#include "DNA_modifier_types.h"
 #include "DNA_particle_types.h"
 #include "DNA_rigidbody_types.h"
 #include "DNA_scene_types.h"
@@ -1838,4 +1839,21 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
 		}
 	}
 
+	{
+		if (!DNA_struct_elem_find(fd->filesdna, "SubsurfModifier", "short", "uv_smooth")) {
+			for (Object *object = bmain->object.first; object != NULL; object = object->id.next) {
+				for (ModifierData *md = object->modifiers.first; md; md = md->next) {
+					if (md->type == eModifierType_Subsurf) {
+						SubsurfModifierData *smd = (SubsurfModifierData *)md;
+						if (smd->flags & eSubsurfModifierFlag_SubsurfUv) {
+							smd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
+						}
+						else {
+							smd->uv_smooth = SUBSURF_UV_SMOOTH_NONE;
+						}
+					}
+				}
+			}
+		}
+	}
 }
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index 02e70a323c7..c53b8e3a5e2 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -139,6 +139,7 @@ typedef enum {
 	eSubsurfModifierFlag_Incremental  = (1 << 0),
 	eSubsurfModifierFlag_DebugIncr    = (1 << 1),
 	eSubsurfModifierFlag_ControlEdges = (1 << 2),
+	/* DEPRECATED, ONLY USED FOR DO-VERSIONS */
 	eSubsurfModifierFlag_SubsurfUv    = (1 << 3),
 } SubsurfModifierFlag;
 
@@ -147,11 +148,22 @@ typedef enum {
 	SUBSURF_TYPE_SIMPLE = 1,
 } eSubsurfModifierType;
 
+typedef enum {
+	SUBSURF_UV_SMOOTH_NONE = 0,
+	SUBSURF_UV_SMOOTH_PRESERVE_CORNERS = 1,
+	SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_AND_JUNCTIONS = 2,
+	SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_JUNCTIONS_AND_CONCAVE = 3,
+	SUBSURF_UV_SMOOTH_PRESERVE_BOUNDARIES = 4,
+	SUBSURF_UV_SMOOTH_ALL = 5,
+} eSubsurfModifierUVSmooth;
+
 typedef struct SubsurfModifierData {
 	ModifierData modifier;
 
 	short subdivType, levels, renderLevels, flags;
-	short use_opensubdiv, pad[3];
+	short uv_smooth;
+	short use_opensubdiv;
+	short pad[2];
 
 	void *emCache, *mCache;
 } SubsurfModifierData;
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index fc0144f3f7b..8fbd906766e 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -1195,6 +1195,26 @@ static PropertyRNA *rna_def_property_subdivision_common(StructRNA *srna, const c
 
 static void rna_def_modifier_subsurf(BlenderRNA *brna)
 {
+	static const EnumPropertyItem prop_uv_smooth_items[] = {
+		{SUBSURF_UV_SMOOTH_NONE, "NONE", 0,
+		 "Sharp", "UVs are not smoothed, boundaries are kept sharp"},
+		{SUBSURF_UV_SMOOTH_PRESERVE_CORNERS, "PRESERVE_CORNERS", 0,
+		 "Smooth, keep corners", "UVs are smoothed, corners on discontinuous boundary are kept sharp"},
+#if 0
+		{SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_AND_JUNCTIONS, "PRESERVE_CORNERS_AND_JUNCTIONS", 0,
+		 "Smooth, keep corners+junctions", "UVs are smoothed, corners on discontinuous boundary and "
+		 "junctions of 3 or more regions are kept sharp"},
+		{SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_JUNCTIONS_AND_CONCAVE, "PRESERVE_CORNERS_JUNCTIONS_AND_CONCAVE", 0,
+		 "Smooth, keep corners+junctions+concave", "UVs are smoothed, corners on discontinuous boundary, "
+		 "junctions of 3 or more regions and darts and concave corners are kept sharp"},
+		{SUBSURF_UV_SMOOTH_PRESERVE_BOUNDARIES, "PRESERVE_BOUNDARIES", 0,
+		 "Smooth, keep corners", "UVs are smoothed, boundaries are kept sharp"},
+		{SUBSURF_UV_SMOOTH_ALL, "PRESERVE_BOUNDARIES", 0,
+		 "Smooth all", "UVs and boundaries are smoothed"},
+#endif
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	StructRNA *srna;
 	PropertyRNA *prop;
 
@@ -1224,9 +1244,10 @@ static void rna_def_modifier_subsurf(BlenderRNA *brna)
 	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_subsurf_uv", PROP_BOOLEAN, PROP_NONE);
-	RNA_def_property_boolean_sdna(prop, NULL, "flags", eSubsurfModifierFlag_SubsurfUv);
-	RNA_def_property_ui_text(prop, "Subdivide UVs", "Use subsurf to subdivide UVs");
+	prop = RNA_def_property(srna, "uv_smooth", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "uv_smooth");
+	RNA_def_property_enum_items(prop, prop_uv_smooth_items);
+	RNA_def_property_ui_text(prop, "UV Smooth", "Controls how smoothing is applied to UVs");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 
 #ifdef WITH_OPENSUBDIV
diff --git a/source/blender/modifiers/intern/MOD_subsurf.c b/source/blender/modifiers/intern/MOD_subsurf.c
index 1b25b4f62dc..82e2d8bfe8d 100644
--- a/source/blender/modifiers/intern/MOD_subsurf.c
+++ b/source/blender/modifiers/intern/MOD_subsurf.c
@@ -65,7 +65,7 @@ static void initData(ModifierData *md)
 
 	smd->levels = 1;
 	smd->renderLevels = 2;
-	smd->flags |= eSubsurfModifierFlag_SubsurfUv;
+	smd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
 }
 
 static void copyData(const ModifierData *md, ModifierData *target, const int flag)
@@ -207,10 +207,32 @@ static void subdiv_settings_init(SubdivSettings *settings,
 	settings->is_simple = (smd->subdivType == SUBSURF_TYPE_SIMPLE);
 	settings->is_adaptive = !settings->is_simple;
 	settings->level = subdiv_levels_for_modifier_get(smd, ctx);
-	settings->fvar_linear_interpolation =
-	        (smd->flags & eSubsurfModifierFlag_SubsurfUv)
-	                ? SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY
-	                : SUBDIV_FVAR_LINEAR_INTERPOLATION_ALL;
+	switch (smd->uv_smooth) {
+		case SUBSURF_UV_SMOOTH_NONE:
+			settings->fvar_linear_interpolation =
+			        SUBDIV_FVAR_LINEAR_INTERPOLATION_ALL;
+			break;
+		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS:
+			settings->fvar_linear_interpolation =
+			        SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY;
+			break;
+		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_AND_JUNCTIONS:
+			settings->fvar_linear_interpolation =
+			        SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_AND_JUNCTIONS;
+			break;
+		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_JUNCTIONS_AND_CONCAVE:
+			settings->fvar_linear_interpolation =
+			        SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_JUNCTIONS_AND_CONCAVE;
+			break;
+		case SUBSURF_UV_SMOOTH_PRESERVE_BOUNDARIES:
+			settings->fvar_linear_interpolation =
+			        SUBDIV_FVAR_LINEAR_INTERPOLATION_BOUNDARIES;
+			break;
+		case SUBSURF_UV_SMOOTH_ALL:
+			settings->fvar_linear_interpolation =
+			        SUBDIV_FVAR_LINEAR_INTERPOLATION_NONE;
+			break;
+	}
 }
 
 static void subdiv_mesh_settings_init(SubdivToMeshSettings *settings,
diff --git a/source/blender/render/intern/source/multires_bake.c b/source/blender/render/intern/source/multires_bake.c
index 0cb9fd7324b..05ccf234638 100644
--- a/source/blender/render/intern/source/multires_bake.c
+++ b/source/blender/render/intern/source/multires_bake.c
@@ -683,7 +683,7 @@ static void *init_heights_data(MultiresBakeRender *bkr, Image *ima)
 
 		if (ss_lvl > 0) {
 			smd.levels = smd.renderLevels = ss_lvl;
-			smd.flags |= eSubsurfModifierFlag_SubsurfUv;
+			smd.uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
 
 			if (bkr->simple)
 				smd.subdivType = ME_SIMPLE_SUBSURF;