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Math Lib: add isect_tri_tri_epsilon_v3 function

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This commit is contained in:
Campbell Barton 2015-07-29 17:48:38 +10:00
parent 792d66527b
commit 90655d06d4
2 changed files with 83 additions and 0 deletions
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5
source/blender/blenlib/BLI_math_geom.h
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@ -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);

78
source/blender/blenlib/intern/math_geom.c
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@ -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 */