1 files changed, 55 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index ef04e5e9bce..d7880e40626 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -2382,6 +2382,38 @@ void accumulate_vertex_normals(float n1[3], float n2[3], float n3[3],
 	}
 }
 
+/* Add weighted face normal component into normals of the face vertices.
+   Caller must pass pre-allocated vdiffs of nverts length. */
+void accumulate_vertex_normals_poly(float **vertnos, float polyno[3],
+	float **vertcos, float vdiffs[][3], int nverts)
+{
+	int i;
+
+	/* calculate normalized edge directions for each edge in the poly */
+	for (i = 0; i < nverts; i++) {
+		sub_v3_v3v3(vdiffs[i], vertcos[(i+1) % nverts], vertcos[i]);
+		normalize_v3(vdiffs[i]);
+	}
+
+	/* accumulate angle weighted face normal */
+	{
+		const float *prev_edge = vdiffs[nverts-1];
+		int i;
+
+		for(i=0; i<nverts; i++) {
+			const float *cur_edge = vdiffs[i];
+			
+			/* calculate angle between the two poly edges incident on
+			   this vertex */
+			const float fac= saacos(-dot_v3v3(cur_edge, prev_edge));
+
+			/* accumulate */
+			madd_v3_v3fl(vertnos[i], polyno, fac);
+			prev_edge = cur_edge;
+		}
+	}
+}
+
 /********************************* Tangents **********************************/
 
 /* For normal map tangents we need to detect uv boundaries, and only average
@@ -3038,3 +3070,26 @@ float form_factor_hemi_poly(float p[3], float n[3], float v1[3], float v2[3], fl
 
 	return contrib;
 }
+
+/* evaluate if entire quad is a proper convex quad */
+ int is_quad_convex_v3(const float *v1, const float *v2, const float *v3, const float *v4)
+ {
+	float nor[3], nor1[3], nor2[3], vec[4][2];
+	int axis_a, axis_b;
+	
+	/* define projection, do both trias apart, quad is undefined! */
+	normal_tri_v3(nor1, v1, v2, v3);
+	normal_tri_v3(nor2, v1, v3, v4);
+	add_v3_v3v3(nor, nor1, nor2);
+
+	axis_dominant_v3(&axis_a, &axis_b, nor);
+
+	vec[0][0]= v1[axis_a]; vec[0][1]= v1[axis_b];
+	vec[1][0]= v2[axis_a]; vec[1][1]= v2[axis_b];
+
+	vec[2][0]= v3[axis_a]; vec[2][1]= v3[axis_b];
+	vec[3][0]= v4[axis_a]; vec[3][1]= v4[axis_b];
+	
+	/* linetests, the 2 diagonals have to instersect to be convex */
+	return (isect_line_line_v2(vec[0], vec[2], vec[1], vec[3]) > 0) ? 1 : 0;
+}