fix for issues in new decimator

- when an edge exists across a quad, dont attempt to triangulate it. (such a case isn't so common anyway)
- silly mistake when checking if anything needed to be done in the modifier, percent was being checked for 1.0 even when not used.

3 files changed, 24 insertions, 12 deletions

diff --git a/source/blender/bmesh/intern/bmesh_decimate_collapse.c b/source/blender/bmesh/intern/bmesh_decimate_collapse.c
index 8f275f6f3d3..5935a844988 100644
--- a/source/blender/bmesh/intern/bmesh_decimate_collapse.c
+++ b/source/blender/bmesh/intern/bmesh_decimate_collapse.c
@@ -231,12 +231,6 @@ static void bm_decim_build_edge_cost(BMesh *bm,
 
 static int bm_decim_triangulate_begin(BMesh *bm)
 {
-#ifdef USE_SAFETY_CHECKS
-	const int check_double_edges = TRUE;
-#else
-	const int check_double_edges = FALSE;
-#endif
-
 	BMIter iter;
 	BMFace *f;
 	// int has_quad;  // could optimize this a little
@@ -285,6 +279,9 @@ static int bm_decim_triangulate_begin(BMesh *bm)
 				l_b = f_l[3];
 			}
 
+#ifdef USE_SAFETY_CHECKS
+			if (BM_edge_exists(l_a->v, l_b->v) == FALSE)
+#endif
 			{
 				BMFace *f_new;
 				BMLoop *l_new;
@@ -293,7 +290,7 @@ static int bm_decim_triangulate_begin(BMesh *bm)
 				 * - if there is a quad that has a free standing edge joining it along
 				 * where we want to split the face, there isnt a good way we can handle this.
 				 * currently that edge will get removed when joining the tris back into a quad. */
-				f_new = BM_face_split(bm, f, l_a->v, l_b->v, &l_new, NULL, check_double_edges);
+				f_new = BM_face_split(bm, f, l_a->v, l_b->v, &l_new, NULL, FALSE);
 
 				if (f_new) {
 					/* the value of this doesn't matter, only that the 2 loops match and have unique values */
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 23d9a9065d5..1ec2c391efc 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -1143,7 +1143,7 @@ static void rna_def_modifier_decimate(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "iterations", PROP_INT, PROP_UNSIGNED);
 	RNA_def_property_int_sdna(prop, NULL, "iter");
 	RNA_def_property_range(prop, 0, SHRT_MAX);
-	RNA_def_property_ui_range(prop, 1, 100, 1, 0);
+	RNA_def_property_ui_range(prop, 0, 100, 1, 0);
 	RNA_def_property_ui_text(prop, "Iterations", "Number of times reduce the geometry (unsubdivide only)");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 
diff --git a/source/blender/modifiers/intern/MOD_decimate.c b/source/blender/modifiers/intern/MOD_decimate.c
index a9bc9cbf83a..cf409c27b2f 100644
--- a/source/blender/modifiers/intern/MOD_decimate.c
+++ b/source/blender/modifiers/intern/MOD_decimate.c
@@ -103,13 +103,28 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 	float *vweights = NULL;
 
 #ifdef USE_TIMEIT
-	 TIMEIT_START(decim);
+	TIMEIT_START(decim);
 #endif
 
-	if (dmd->percent == 1.0f) {
-		return dm;
+	switch (dmd->mode) {
+		case MOD_DECIM_MODE_COLLAPSE:
+			if (dmd->percent == 1.0f) {
+				return dm;
+			}
+			break;
+		case MOD_DECIM_MODE_UNSUBDIV:
+			if (dmd->iter == 0) {
+				return dm;
+			}
+			break;
+		case MOD_DECIM_MODE_DISSOLVE:
+			if (dmd->angle == 0.0f) {
+				return dm;
+			}
+			break;
 	}
-	else if (dm->getNumPolys(dm) <= 3) {
+
+	if (dm->getNumPolys(dm) <= 3) {
 		modifier_setError(md, "%s", TIP_("Modifier requires more than 3 input faces"));
 		return dm;
 	}