[Bf-blender-cvs] [3debcc8] master: Math Lib: improve area calculation
Campbell Barton
noreply at git.blender.org
Tue Jan 13 09:10:52 CET 2015
Commit: 3debcc8b517ece352aa325cfd61adc0b16cf91da
Author: Campbell Barton
Date: Tue Jan 13 19:01:40 2015 +1100
Branches: master
https://developer.blender.org/rB3debcc8b517ece352aa325cfd61adc0b16cf91da
Math Lib: improve area calculation
- area_quad_v3 now works correctly with concave quads.
- add area_squared_*** functions, to use when comparing to avoid a sqrt().
===================================================================
M source/blender/blenkernel/intern/mesh_evaluate.c
M source/blender/blenlib/BLI_math_geom.h
M source/blender/blenlib/intern/math_geom.c
M source/blender/blenlib/intern/math_geom_inline.c
M source/blender/bmesh/intern/bmesh_polygon.c
===================================================================
diff --git a/source/blender/blenkernel/intern/mesh_evaluate.c b/source/blender/blenkernel/intern/mesh_evaluate.c
index 4c9e446..915abdb 100644
--- a/source/blender/blenkernel/intern/mesh_evaluate.c
+++ b/source/blender/blenkernel/intern/mesh_evaluate.c
@@ -896,13 +896,6 @@ float BKE_mesh_calc_poly_area(MPoly *mpoly, MLoop *loopstart,
mvarray[loopstart[2].v].co
);
}
- else if (mpoly->totloop == 4) {
- return area_quad_v3(mvarray[loopstart[0].v].co,
- mvarray[loopstart[1].v].co,
- mvarray[loopstart[2].v].co,
- mvarray[loopstart[3].v].co
- );
- }
else {
int i;
MLoop *l_iter = loopstart;
diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index ee99f86..495aa6b 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -52,16 +52,23 @@ float normal_quad_v3(float r[3], const float a[3], const float b[3], const float
float normal_poly_v3(float r[3], const float verts[][3], unsigned int nr);
MINLINE float area_tri_v2(const float a[2], const float b[2], const float c[2]);
+MINLINE float area_squared_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_squared_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_squared_quad_v3(const float a[3], const float b[3], const float c[3], const float d[3]);
float area_poly_v3(const float verts[][3], unsigned int nr);
float area_poly_v2(const float verts[][2], unsigned int nr);
+float area_squared_poly_v3(const float verts[][3], unsigned int nr);
+float area_squared_poly_v2(const float verts[][2], unsigned int nr);
+float area_poly_signed_v2(const float verts[][2], unsigned int nr);
float cotangent_tri_weight_v3(const float v1[3], const float v2[3], const float v3[3]);
void cross_tri_v3(float n[3], const float v1[3], const float v2[3], const float v3[3]);
MINLINE float cross_tri_v2(const float v1[2], const float v2[2], const float v3[2]);
+void cross_poly_v3(float n[3], const float verts[][3], unsigned int nr);
float cross_poly_v2(const float verts[][2], unsigned int nr);
/********************************* Planes **********************************/
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index 59d9cf8..05a527c 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -109,58 +109,44 @@ float normal_quad_v3(float n[3], const float v1[3], const float v2[3], const flo
*/
float normal_poly_v3(float n[3], const float verts[][3], unsigned int nr)
{
- const float *v_prev = verts[nr - 1];
- const float *v_curr = verts[0];
- unsigned int i;
-
- zero_v3(n);
-
- /* Newell's Method */
- for (i = 0; i < nr; v_prev = v_curr, v_curr = verts[++i]) {
- add_newell_cross_v3_v3v3(n, v_prev, v_curr);
- }
-
+ cross_poly_v3(n, verts, nr);
return normalize_v3(n);
}
-/* only convex Quadrilaterals */
float area_quad_v3(const float v1[3], const float v2[3], const float v3[3], const float v4[3])
{
- float len, vec1[3], vec2[3], n[3];
-
- sub_v3_v3v3(vec1, v2, v1);
- sub_v3_v3v3(vec2, v4, v1);
- cross_v3_v3v3(n, vec1, vec2);
- len = len_v3(n);
-
- sub_v3_v3v3(vec1, v4, v3);
- sub_v3_v3v3(vec2, v2, v3);
- cross_v3_v3v3(n, vec1, vec2);
- len += len_v3(n);
+ const float verts[4][3] = {{UNPACK3(v1)}, {UNPACK3(v2)}, {UNPACK3(v3)}, {UNPACK3(v4)}};
+ return area_poly_v3(verts, 4);
+}
- return (len / 2.0f);
+float area_squared_quad_v3(const float v1[3], const float v2[3], const float v3[3], const float v4[3])
+{
+ const float verts[4][3] = {{UNPACK3(v1)}, {UNPACK3(v2)}, {UNPACK3(v3)}, {UNPACK3(v4)}};
+ return area_squared_poly_v3(verts, 4);
}
/* Triangles */
float area_tri_v3(const float v1[3], const float v2[3], const float v3[3])
{
- float vec1[3], vec2[3], n[3];
-
- sub_v3_v3v3(vec1, v3, v2);
- sub_v3_v3v3(vec2, v1, v2);
- cross_v3_v3v3(n, vec1, vec2);
+ float n[3];
+ cross_tri_v3(n, v1, v2, v3);
+ return len_v3(n) * 0.5f;
+}
- return len_v3(n) / 2.0f;
+float area_squared_tri_v3(const float v1[3], const float v2[3], const float v3[3])
+{
+ float n[3];
+ cross_tri_v3(n, v1, v2, v3);
+ mul_v3_fl(n, 0.5f);
+ return len_squared_v3(n);
}
float area_tri_signed_v3(const float v1[3], const float v2[3], const float v3[3], const float normal[3])
{
- float area, vec1[3], vec2[3], n[3];
+ float area, n[3];
- sub_v3_v3v3(vec1, v3, v2);
- sub_v3_v3v3(vec2, v1, v2);
- cross_v3_v3v3(n, vec1, vec2);
- area = len_v3(n) / 2.0f;
+ cross_tri_v3(n, v1, v2, v3);
+ area = len_v3(n) * 0.5f;
/* negate area for flipped triangles */
if (dot_v3v3(n, normal) < 0.0f)
@@ -172,7 +158,17 @@ float area_tri_signed_v3(const float v1[3], const float v2[3], const float v3[3]
float area_poly_v3(const float verts[][3], unsigned int nr)
{
float n[3];
- return normal_poly_v3(n, verts, nr) * 0.5f;
+ cross_poly_v3(n, verts, nr);
+ return len_v3(n) * 0.5f;
+}
+
+float area_squared_poly_v3(const float verts[][3], unsigned int nr)
+{
+ float n[3];
+
+ cross_poly_v3(n, verts, nr);
+ mul_v3_fl(n, 0.5f);
+ return len_squared_v3(n);
}
/**
@@ -200,11 +196,36 @@ float cross_poly_v2(const float verts[][2], unsigned int nr)
return cross;
}
+void cross_poly_v3(float n[3], const float verts[][3], unsigned int nr)
+{
+ const float *v_prev = verts[nr - 1];
+ const float *v_curr = verts[0];
+ unsigned int i;
+
+ zero_v3(n);
+
+ /* Newell's Method */
+ for (i = 0; i < nr; v_prev = v_curr, v_curr = verts[++i]) {
+ add_newell_cross_v3_v3v3(n, v_prev, v_curr);
+ }
+}
+
float area_poly_v2(const float verts[][2], unsigned int nr)
{
return fabsf(0.5f * cross_poly_v2(verts, nr));
}
+float area_poly_signed_v2(const float verts[][2], unsigned int nr)
+{
+ return (0.5f * cross_poly_v2(verts, nr));
+}
+
+float area_squared_poly_v2(const float verts[][2], unsigned int nr)
+{
+ float area = area_poly_signed_v2(verts, nr);
+ return area * area;
+}
+
float cotangent_tri_weight_v3(const float v1[3], const float v2[3], const float v3[3])
{
float a[3], b[3], c[3], c_len;
diff --git a/source/blender/blenlib/intern/math_geom_inline.c b/source/blender/blenlib/intern/math_geom_inline.c
index 5a64ed6..44b1768 100644
--- a/source/blender/blenlib/intern/math_geom_inline.c
+++ b/source/blender/blenlib/intern/math_geom_inline.c
@@ -54,6 +54,12 @@ 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));
}
+MINLINE float area_squared_tri_v2(const float v1[2], const float v2[2], const float v3[2])
+{
+ float area = area_tri_signed_v2(v1, v2, v3);
+ return area * area;
+}
+
/****************************** Spherical Harmonics **************************/
MINLINE void zero_sh(float r[9])
diff --git a/source/blender/bmesh/intern/bmesh_polygon.c b/source/blender/bmesh/intern/bmesh_polygon.c
index f2c4261..e4aa4bb 100644
--- a/source/blender/bmesh/intern/bmesh_polygon.c
+++ b/source/blender/bmesh/intern/bmesh_polygon.c
@@ -214,9 +214,6 @@ float BM_face_calc_area(BMFace *f)
if (f->len == 3) {
area = area_tri_v3(verts[0], verts[1], verts[2]);
}
- else if (f->len == 4) {
- area = area_quad_v3(verts[0], verts[1], verts[2], verts[3]);
- }
else {
area = area_poly_v3((const float (*)[3])verts, f->len);
}
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