optimize ngon angle calculation in solidify modifier (was doing prev/next vector subtract and normalize for every vertex). now store the previous normalized vector for re-use.

also add BKE_mesh_poly_calc_angles() which is mostly a reference for now.

1 files changed, 48 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index ecf6fd8e5de..3ccd09257e6 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -3103,3 +3103,51 @@ void BKE_mesh_tessface_clear(Mesh *mesh)
 {
 	mesh_tessface_clear_intern(mesh, TRUE);
 }
+
+#if 0 /* slow version of the function below */
+void BKE_mesh_poly_calc_angles(MVert *mvert, MLoop *mloop,
+                                 MPoly *mp, float angles[])
+{
+	MLoop *ml;
+
+	int j;
+	for (j = 0, ml = mloop + mp->loopstart; j < mp->totloop; j++, ml++) {
+		MLoop *ml_prev = ME_POLY_LOOP_PREV(mloop, mp, j);
+		MLoop *ml_next = ME_POLY_LOOP_NEXT(mloop, mp, j);
+
+		float e1[3], e2[3];
+
+		sub_v3_v3v3(e1, mvert[ml_next->v].co, mvert[ml->v].co);
+		sub_v3_v3v3(e2, mvert[ml_prev->v].co, mvert[ml->v].co);
+
+		angles[j] = (float)M_PI - angle_v3v3(e1, e2);
+	}
+}
+
+#else /* equivalent the function above but avoid multiple subtractions + normalize */
+
+void BKE_mesh_poly_calc_angles(MVert *mvert, MLoop *mloop,
+                                 MPoly *mp, float angles[])
+{
+	MLoop *ml = mloop + mp->loopstart;
+	float nor_prev[3];
+	float nor_next[3];
+
+	int i_this = mp->totloop - 1;
+	int i_next = 0;
+
+	sub_v3_v3v3(nor_prev, mvert[ml[i_this - 1].v].co, mvert[ml[i_this].v].co);
+	normalize_v3(nor_prev);
+
+	while (i_next < mp->totloop) {
+		sub_v3_v3v3(nor_next, mvert[ml[i_this].v].co, mvert[ml[i_next].v].co);
+		normalize_v3(nor_next);
+		angles[i_this] = angle_normalized_v3v3(nor_prev, nor_next);
+
+		/* step */
+		copy_v3_v3(nor_prev, nor_next);
+		i_this = i_next;
+		i_next++;
+	}
+}
+#endif