solidify option to flip normals

4 files changed, 27 insertions, 19 deletions

diff --git a/release/scripts/startup/bl_ui/properties_data_modifier.py b/release/scripts/startup/bl_ui/properties_data_modifier.py
index 72429743c93..2e980f776a1 100644
--- a/release/scripts/startup/bl_ui/properties_data_modifier.py
+++ b/release/scripts/startup/bl_ui/properties_data_modifier.py
@@ -682,6 +682,7 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
         row = row.row()
         row.active = md.use_rim
         row.prop(md, "material_offset_rim", text="Rim")
+        sub.prop(md, "use_flip_normals")
 
     def SUBSURF(self, layout, ob, md):
         layout.row().prop(md, "subdivision_type", expand=True)
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index a5a540ff6b4..cf8b08549f6 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -728,11 +728,12 @@ typedef struct SolidifyModifierData {
 	short mat_ofs_rim;
 } SolidifyModifierData;
 
-#define MOD_SOLIDIFY_RIM			(1<<0)
-#define MOD_SOLIDIFY_EVEN			(1<<1)
-#define MOD_SOLIDIFY_NORMAL_CALC	(1<<2)
-#define MOD_SOLIDIFY_VGROUP_INV		(1<<3)
-#define MOD_SOLIDIFY_RIM_MATERIAL	(1<<4) /* deprecated, used in do_versions */
+#define MOD_SOLIDIFY_RIM            (1 << 0)
+#define MOD_SOLIDIFY_EVEN           (1 << 1)
+#define MOD_SOLIDIFY_NORMAL_CALC    (1 << 2)
+#define MOD_SOLIDIFY_VGROUP_INV     (1 << 3)
+#define MOD_SOLIDIFY_RIM_MATERIAL   (1 << 4) /* deprecated, used in do_versions */
+#define MOD_SOLIDIFY_FLIP           (1 << 5)
 
 typedef struct ScrewModifierData {
 	ModifierData modifier;
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 659c04015df..21a01cf43a8 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -2553,8 +2553,11 @@ static void rna_def_modifier_solidify(BlenderRNA *brna)
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", MOD_SOLIDIFY_VGROUP_INV);
 	RNA_def_property_ui_text(prop, "Vertex Group Invert", "Invert the vertex group influence");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
-	
-	
+
+	prop = RNA_def_property(srna, "use_flip_normals", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", MOD_SOLIDIFY_FLIP);
+	RNA_def_property_ui_text(prop, "Flip Normals", "Invert the face direction");
+	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 }
 
 static void rna_def_modifier_screw(BlenderRNA *brna)
diff --git a/source/blender/modifiers/intern/MOD_solidify.c b/source/blender/modifiers/intern/MOD_solidify.c
index 5d31420da86..f29455447bb 100644
--- a/source/blender/modifiers/intern/MOD_solidify.c
+++ b/source/blender/modifiers/intern/MOD_solidify.c
@@ -50,19 +50,14 @@
 #include "MOD_modifiertypes.h"
 #include "MOD_util.h"
 
+/* *** derived mesh high quality normal calculation function  *** */
+/* could be exposed for other functions to use */
+
 typedef struct EdgeFaceRef {
 	int f1; /* init as -1 */
 	int f2;
 } EdgeFaceRef;
 
-/* spesific function for solidify - define locally */
-BLI_INLINE void madd_v3v3short_fl(float r[3], const short a[3], const float f)
-{
-	r[0] += (float)a[0] * f;
-	r[1] += (float)a[1] * f;
-	r[2] += (float)a[2] * f;
-}
-
 static void dm_calc_normal(DerivedMesh *dm, float (*temp_nors)[3])
 {
 	int i, numVerts, numEdges, numFaces;
@@ -207,6 +202,13 @@ static CustomDataMask requiredDataMask(Object *UNUSED(ob), ModifierData *md)
 	return dataMask;
 }
 
+/* spesific function for solidify - define locally */
+BLI_INLINE void madd_v3v3short_fl(float r[3], const short a[3], const float f)
+{
+	r[0] += (float)a[0] * f;
+	r[1] += (float)a[1] * f;
+	r[2] += (float)a[2] * f;
+}
 
 static DerivedMesh *applyModifier(ModifierData *md, Object *ob, 
                                   DerivedMesh *dm,
@@ -249,6 +251,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 	const float ofs_new  = smd->offset + ofs_orig;
 	const float offset_fac_vg = smd->offset_fac_vg;
 	const float offset_fac_vg_inv = 1.0f - smd->offset_fac_vg;
+	const int   do_flip = (smd->flag & MOD_SOLIDIFY_FLIP) != 0;
 
 	/* weights */
 	MDeformVert *dvert, *dv = NULL;
@@ -420,7 +423,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 
 		if (ofs_new != 0.0f) {
 			scalar_short = scalar_short_vgroup = ofs_new / 32767.0f;
-			mv = mvert + ((ofs_new >= ofs_orig) ? 0 : numVerts);
+			mv = mvert + (((ofs_new >= ofs_orig) == do_flip) ? numVerts : 0);
 			dv = dvert;
 			for (i = 0; i < numVerts; i++, mv++) {
 				if (dv) {
@@ -435,7 +438,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 
 		if (ofs_orig != 0.0f) {
 			scalar_short = scalar_short_vgroup = ofs_orig / 32767.0f;
-			mv = mvert + ((ofs_new >= ofs_orig) ? numVerts : 0); /* as above but swapped, intentional use 'ofs_new' */
+			mv = mvert + (((ofs_new >= ofs_orig) == do_flip) ? 0 : numVerts); /* as above but swapped, intentional use 'ofs_new' */
 			dv = dvert;
 			for (i = 0; i < numVerts; i++, mv++) {
 				if (dv) {
@@ -536,7 +539,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 		}
 
 		if (ofs_new) {
-			mv = mvert + ((ofs_new >= ofs_orig) ? 0 : numVerts);
+			mv = mvert + (((ofs_new >= ofs_orig) == do_flip) ? numVerts : 0);
 
 			for (i = 0; i < numVerts; i++, mv++) {
 				if (vert_accum[i]) { /* zero if unselected */
@@ -547,7 +550,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 
 		if (ofs_orig) {
 			/* same as above but swapped, intentional use of 'ofs_new' */
-			mv = mvert + ((ofs_new >= ofs_orig) ? numVerts : 0);
+			mv = mvert + (((ofs_new >= ofs_orig) == do_flip) ? 0 : numVerts);
 
 			for (i = 0; i < numVerts; i++, mv++) {
 				if (vert_accum[i]) { /* zero if unselected */