Math Library: add functions cross_poly_v2, cross_tri_v2

also added utility macro for removing elements in the middle of an array

4 files changed, 43 insertions, 22 deletions

diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index f815716148b..9073fbb8b80 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -54,14 +54,17 @@ void cent_quad_v3(float r[3], const float a[3], const float b[3], const float c[
 float normal_tri_v3(float r[3], const float a[3], const float b[3], const float c[3]);
 float normal_quad_v3(float r[3], const float a[3], const float b[3], const float c[3], const float d[3]);
 
-float area_tri_v2(const float a[2], const float b[2], const float c[2]);
-float area_tri_signed_v2(const float v1[2], const float v2[2], const float v3[2]);
+MINLINE float area_tri_v2(const float a[2], const float b[2], const float c[2]);
+MINLINE float area_tri_signed_v2(const float v1[2], const float v2[2], const float v3[2]);
 float area_tri_v3(const float a[3], const float b[3], const float c[3]);
 float area_tri_signed_v3(const float v1[3], const float v2[3], const float v3[3], const float normal[3]);
 float area_quad_v3(const float a[3], const float b[3], const float c[3], const float d[3]);
 float area_poly_v3(int nr, float verts[][3], const float normal[3]);
 float area_poly_v2(int nr, float verts[][2]);
 
+MINLINE float cross_tri_v2(const float v1[2], const float v2[2], const float v3[2]);
+float cross_poly_v2(int nr, float verts[][2]);
+
 /********************************* Planes **********************************/
 
 void  plane_from_point_normal_v3(float r_plane[4], const float plane_co[3], const float plane_no[3]);
diff --git a/source/blender/blenlib/BLI_utildefines.h b/source/blender/blenlib/BLI_utildefines.h
index 0f7c0ac0fd8..db607d6d0c7 100644
--- a/source/blender/blenlib/BLI_utildefines.h
+++ b/source/blender/blenlib/BLI_utildefines.h
@@ -300,6 +300,12 @@
 #define ARRAY_HAS_ITEM(arr_item, arr_start, tot) \
 	((unsigned int)((arr_item) - (arr_start)) < (unsigned int)(tot))
 
+#define ARRAY_DELETE(arr, index, tot_delete, tot)  { \
+		BLI_assert(index + tot_delete <= tot);  \
+		memmove(&(arr)[(index)], \
+		        &(arr)[(index) + (tot_delete)], \
+		         (((tot) - (index)) - (tot_delete)) * sizeof(*(arr))); \
+	} (void)0
 
 /* Warning-free macros for storing ints in pointers. Use these _only_
  * for storing an int in a pointer, not a pointer in an int (64bit)! */
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index 0d15eede9ea..45612335323 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -88,16 +88,6 @@ float normal_quad_v3(float n[3], const float v1[3], const float v2[3], const flo
 	return normalize_v3(n);
 }
 
-float area_tri_v2(const float v1[2], const float v2[2], const float v3[2])
-{
-	return 0.5f * fabsf((v1[0] - v2[0]) * (v2[1] - v3[1]) + (v1[1] - v2[1]) * (v3[0] - v2[0]));
-}
-
-float area_tri_signed_v2(const float v1[2], const float v2[2], const float v3[2])
-{
-	return 0.5f * ((v1[0] - v2[0]) * (v2[1] - v3[1]) + (v1[1] - v2[1]) * (v3[0] - v2[0]));
-}
-
 /* only convex Quadrilaterals */
 float area_quad_v3(const float v1[3], const float v2[3], const float v3[3], const float v4[3])
 {
@@ -157,30 +147,35 @@ float area_poly_v3(int nr, float verts[][3], const float normal[3])
 	area = 0.0f;
 	for (a = 0; a < nr; a++) {
 		area += (co_curr[px] - co_prev[px]) * (co_curr[py] + co_prev[py]);
-		co_prev = verts[a];
-		co_curr = verts[a + 1];
+		co_prev = co_curr;
+		co_curr += 3;
 	}
 
 	return fabsf(0.5f * area / max);
 }
 
-float area_poly_v2(int nr, float verts[][2])
+float cross_poly_v2(int nr, float verts[][2])
 {
 	int a;
-	float area;
-	float *co_curr, *co_prev;
+	float cross;
+	const float *co_curr, *co_prev;
 
 	/* The Trapezium Area Rule */
 	co_prev = verts[nr - 1];
 	co_curr = verts[0];
-	area = 0.0f;
+	cross = 0.0f;
 	for (a = 0; a < nr; a++) {
-		area += (co_curr[0] - co_prev[0]) * (co_curr[1] + co_prev[1]);
-		co_prev = verts[a];
-		co_curr = verts[a + 1];
+		cross += (co_curr[0] - co_prev[0]) * (co_curr[1] + co_prev[1]);
+		co_prev = co_curr;
+		co_curr += 2;
 	}
 
-	return fabsf(0.5f * area);
+	return cross;
+}
+
+float area_poly_v2(int nr, float verts[][2])
+{
+	return fabsf(0.5f * cross_poly_v2(nr, verts));
 }
 
 /********************************* Planes **********************************/
diff --git a/source/blender/blenlib/intern/math_geom_inline.c b/source/blender/blenlib/intern/math_geom_inline.c
index ac5c0033067..1910b964d78 100644
--- a/source/blender/blenlib/intern/math_geom_inline.c
+++ b/source/blender/blenlib/intern/math_geom_inline.c
@@ -34,6 +34,23 @@
 
 #include <string.h>
 
+/********************************** Polygons *********************************/
+
+MINLINE float cross_tri_v2(const float v1[2], const float v2[2], const float v3[2])
+{
+	return (v1[0] - v2[0]) * (v2[1] - v3[1]) + (v1[1] - v2[1]) * (v3[0] - v2[0]);
+}
+
+MINLINE float area_tri_signed_v2(const float v1[2], const float v2[2], const float v3[2])
+{
+	return 0.5f * ((v1[0] - v2[0]) * (v2[1] - v3[1]) + (v1[1] - v2[1]) * (v3[0] - v2[0]));
+}
+
+MINLINE float area_tri_v2(const float v1[2], const float v2[2], const float v3[2])
+{
+	return fabsf(area_tri_signed_v2(v1, v2, v3));
+}
+
 /****************************** Spherical Harmonics **************************/
 
 MINLINE void zero_sh(float r[9])