diff options
-rw-r--r-- | source/blender/blenlib/BLI_math_geom.h | 5 | ||||
-rw-r--r-- | source/blender/blenlib/intern/math_geom.c | 78 |
2 files changed, 83 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h index 8820b88b9ac..5124da4cd35 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 3fb6de47f5f..e05cd7c300b 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 */ |