Commit: 90655d06d410b831ff199cfc6f080004cf08ce8c
Author: Campbell Barton
Date: Wed Jul 29 17:48:38 2015 +1000
Branches: master
https://developer.blender.org/rB90655d06d410b831ff199cfc6f080004cf08ce8c
Math Lib: add isect_tri_tri_epsilon_v3 function
===================================================================
M source/blender/blenlib/BLI_math_geom.h
M source/blender/blenlib/intern/math_geom.c
===================================================================
diff --git a/source/blender/blenlib/BLI_math_geom.h
b/source/blender/blenlib/BLI_math_geom.h
index 8820b88..5124da4 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -187,6 +187,11 @@ bool isect_ray_tri_threshold_v3(const float p1[3], const
float d[3],
const float v0[3], const float v1[3], const
float v2[3], float *r_lambda, float r_uv[2], const float threshold);
bool isect_ray_tri_epsilon_v3(const float p1[3], const float d[3],
const float v0[3], const float v1[3], const
float v2[3], float *r_lambda, float r_uv[2], const float epsilon);
+bool isect_tri_tri_epsilon_v3(
+ const float t_a0[3], const float t_a1[3], const float t_a2[3],
+ const float t_b0[3], const float t_b1[3], const float t_b2[3],
+ float r_i1[3], float r_i2[3],
+ const float epsilon);
/* point in polygon */
bool isect_point_poly_v2(const float pt[2], const float verts[][2], const
unsigned int nr, const bool use_holes);
diff --git a/source/blender/blenlib/intern/math_geom.c
b/source/blender/blenlib/intern/math_geom.c
index 3fb6de4..e05cd7c 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -1475,6 +1475,84 @@ bool isect_plane_plane_v3(float r_isect_co[3], float
r_isect_no[3],
return isect_line_plane_v3(r_isect_co, plane_a_co, plane_a_co_other,
plane_b_co, plane_b_no);
}
+/**
+ * Intersect two triangles.
+ *
+ * \param r_i1, r_i2: Optional arguments to retrieve the overlapping edge
between the 2 triangles.
+ * \return true when the triangles intersect.
+ *
+ * \note intersections between coplanar triangles are currently undetected.
+ */
+bool isect_tri_tri_epsilon_v3(
+ const float t_a0[3], const float t_a1[3], const float t_a2[3],
+ const float t_b0[3], const float t_b1[3], const float t_b2[3],
+ float r_i1[3], float r_i2[3],
+ const float epsilon)
+{
+ const float *tri_pair[2][3] = {{t_a0, t_a1, t_a2}, {t_b0, t_b1, t_b2}};
+ float no_a[3], no_b[3];
+ float isect_co[3], isect_no[3];
+
+ BLI_assert((r_i1 != NULL) == (r_i2 != NULL));
+
+ normal_tri_v3(no_a, UNPACK3(tri_pair[0]));
+ normal_tri_v3(no_b, UNPACK3(tri_pair[1]));
+
+ if (isect_plane_plane_v3(isect_co, isect_no, t_a0, no_a, t_b0, no_b)) {
+ float isect_co_other[3];
+ struct {
+ float min, max;
+ } range[2] = {{FLT_MAX, -FLT_MAX}, {FLT_MAX, -FLT_MAX}};
+ int t;
+
+ add_v3_v3v3(isect_co_other, isect_co, isect_no);
+
+ /* For both triangles, find the overlap with the line defined
by (isect_co, isect_co_other).
+ * When the ranges overlap we know the triangles do too. */
+ for (t = 0; t < 2; t++) {
+ int j, j_prev;
+
+ for (j = 0, j_prev = 2; j < 3; j_prev = j++) {
+ /* intersection point on the line intersecting
both planes */
+ float ix_span[3];
+ /* intersection point on the triangles edge */
+ float ix_tri[3];
+
+ if (isect_line_line_epsilon_v3(
+ isect_co, isect_co_other,
+ tri_pair[t][j], tri_pair[t][j_prev],
+ ix_span, ix_tri,
+ epsilon) == 2)
+ {
+ const float edge_fac =
line_point_factor_v3(ix_tri, tri_pair[t][j], tri_pair[t][j_prev]);
+ if (edge_fac >= -epsilon && edge_fac <=
1.0f + epsilon) {
+ const float span_fac =
dist_signed_squared_to_plane3_v3(ix_tri, isect_no);
+ range[t].min =
min_ff(range[t].min, span_fac);
+ range[t].max =
max_ff(range[t].max, span_fac);
+ }
+ }
+ }
+
+ if (range[t].min == FLT_MAX) {
+ return false;
+ }
+ }
+
+ if (((range[0].min > range[1].max) ||
+ (range[0].max < range[1].min)) == 0)
+ {
+ if (r_i1 && r_i2) {
+ project_plane_v3_v3v3(isect_co, isect_co,
isect_no);
+ madd_v3_v3v3fl(r_i1, isect_co, isect_no,
sqrtf_signed(max_ff(range[0].min, range[1].min)));
+ madd_v3_v3v3fl(r_i2, isect_co, isect_no,
sqrtf_signed(min_ff(range[0].max, range[1].max)));
+ }
+
+ return true;
+ }
+ }
+
+ return false;
+}
/* Adapted from the paper by Kasper Fauerby */
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