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Fix for isect_tri_tri_epsilon_v3 w/ small faces 

tris with ~1e-05 edge lengths would fail
This commit is contained in:
Campbell Barton 2015-09-04 22:25:28 +10:00
parent 1d71ad2eaa
commit 39752eb912
1 changed files with 7 additions and 6 deletions
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13
source/blender/blenlib/intern/math_geom.c
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@ -1668,7 +1668,9 @@ bool isect_tri_tri_epsilon_v3(
plane_a[3] = -dot_v3v3(plane_a, t_a0);
plane_b[3] = -dot_v3v3(plane_b, t_b0);
if (isect_plane_plane_v3(plane_a, plane_b, plane_co, plane_no)) {
if (isect_plane_plane_v3(plane_a, plane_b, plane_co, plane_no) &&
(normalize_v3(plane_no) > epsilon))
{
/**
* Implementation note: its simpler to project the triangles onto the intersection plane
* before intersecting their edges with the ray, defined by 'isect_plane_plane_v3'.
@ -1681,10 +1683,6 @@ bool isect_tri_tri_epsilon_v3(
int t;
float co_proj[3];
/* only for numeric stability
* (and so we can call 'closest_to_plane3_normalized_v3' below) */
normalize_v3(plane_no);
closest_to_plane3_normalized_v3(co_proj, plane_no, plane_co);
/* For both triangles, find the overlap with the line defined by the ray [co_proj, plane_no].
@ -1698,7 +1696,10 @@ bool isect_tri_tri_epsilon_v3(
closest_to_plane3_normalized_v3(tri_proj[2], plane_no, tri_pair[t][2]);
for (j = 0, j_prev = 2; j < 3; j_prev = j++) {
const float edge_fac = line_point_factor_v3_ex(co_proj, tri_proj[j_prev], tri_proj[j], epsilon, -1.0f);
/* note that its important to have a very small nonzero epsilon here
* otherwise this fails for very small faces.
* However if its too small, large adjacent faces will count as intersecting */
const float edge_fac = line_point_factor_v3_ex(co_proj, tri_proj[j_prev], tri_proj[j], 1e-10f, -1.0f);
/* ignore collinear lines, they are either an edge shared between 2 tri's
* (which runs along [co_proj, plane_no], but can be safely ignored).
*