Revision: 55966
http://sourceforge.net/p/brlcad/code/55966
Author: phoenixyjll
Date: 2013-07-08 06:30:18 +0000 (Mon, 08 Jul 2013)
Log Message:
-----------
The inverse of the matrix may fail, and actually we don't need to solve a 3*3
system because x+y+z==1. And triangle intersections should handle the cases
where the two planes are coincident.
Modified Paths:
--------------
brlcad/trunk/src/libbrep/intersect.cpp
Modified: brlcad/trunk/src/libbrep/intersect.cpp
===================================================================
--- brlcad/trunk/src/libbrep/intersect.cpp 2013-07-08 05:06:53 UTC (rev
55965)
+++ brlcad/trunk/src/libbrep/intersect.cpp 2013-07-08 06:30:18 UTC (rev
55966)
@@ -1591,16 +1591,21 @@
}
ON_3dPoint BarycentricCoordinate(ON_3dPoint &pt)
{
- ON_Matrix M(3, 3);
- M[0][0] = A[0], M[0][1] = B[0], M[0][2] = C[0];
- M[1][0] = A[1], M[1][1] = B[1], M[1][2] = C[1];
- M[2][0] = A[2], M[2][1] = B[2], M[2][2] = C[2];
- M.Invert(0.0);
- ON_Matrix MX(3, 1);
- MX[0][0] = pt[0], MX[1][0] = pt[1], MX[2][0] = pt[2];
- M.Multiply(M, MX);
- return ON_3dPoint(M[0][0], M[1][0], M[2][0]);
+ double x, y, z, pivot_ratio;
+ if (ON_Solve2x2(A[0]-C[0], B[0]-C[0], A[1]-C[1], B[1]-C[1], pt[0]-C[0],
pt[1]-C[1], &x, &y, &pivot_ratio) == 2)
+ return ON_3dPoint(x, y, 1-x-y);
+ if (ON_Solve2x2(A[0]-C[0], B[0]-C[0], A[2]-C[2], B[2]-C[2], pt[0]-C[0],
pt[2]-C[2], &x, &z, &pivot_ratio) == 2)
+ return ON_3dPoint(x, 1-x-z, z);
+ if (ON_Solve2x2(A[1]-C[1], B[1]-C[1], A[2]-C[2], B[2]-C[2], pt[1]-C[1],
pt[2]-C[2], &y, &z, &pivot_ratio) == 2)
+ return ON_3dPoint(1-y-z, y, z);
+ return ON_3dPoint::UnsetPoint;
}
+ void GetLineSegments(ON_Line line[3]) const
+ {
+ line[0] = ON_Line(A, B);
+ line[1] = ON_Line(A, C);
+ line[2] = ON_Line(B, C);
+ }
};
@@ -1610,6 +1615,33 @@
ON_Plane plane_a(TriA.A, TriA.B, TriA.C);
ON_Plane plane_b(TriB.A, TriB.B, TriB.C);
ON_Line intersect;
+ if (plane_a.Normal().IsParallelTo(plane_b.Normal())) {
+ if (!ON_NearZero(plane_a.DistanceTo(plane_b.origin))) {
+ // parallel
+ return false;
+ }
+ // The two triangles are in the same plane.
+ ON_3dPoint pt(0.0, 0.0, 0.0);
+ int count = 0;
+ ON_Line lineA[3], lineB[3];
+ TriA.GetLineSegments(lineA);
+ TriB.GetLineSegments(lineB);
+ for (int i = 0; i < 3; i++) {
+ for (int j = 0; j < 3; j++) {
+ double t_a, t_b;
+ if (ON_IntersectLineLine(lineA[i], lineB[j], &t_a, &t_b,
ON_ZERO_TOLERANCE, true)) {
+ // we don't care if they are parallel or coincident
+ pt += lineA[i].PointAt(t_a);
+ count++;
+ }
+ }
+ }
+ if (!count)
+ return false;
+ center = pt/count;
+ return true;
+ }
+
if (!ON_Intersect(plane_a, plane_b, intersect))
return false;
ON_3dVector line_normal = ON_CrossProduct(plane_a.Normal(),
intersect.Direction());
@@ -1619,22 +1651,23 @@
double dp2 = ON_DotProduct(TriA.B - intersect.from, line_normal);
double dp3 = ON_DotProduct(TriA.C - intersect.from, line_normal);
- int points_on_one_side = (dp1 >= -ON_ZERO_TOLERANCE) + (dp2 >=
-ON_ZERO_TOLERANCE) + (dp3 >= -ON_ZERO_TOLERANCE);
- if (points_on_one_side == 0 || points_on_one_side == 3)
+ int points_on_line = ON_NearZero(dp1) + ON_NearZero(dp2) +
ON_NearZero(dp3);
+ int points_on_one_side = (dp1 >= ON_ZERO_TOLERANCE) + (dp2 >=
ON_ZERO_TOLERANCE) + (dp3 >= ON_ZERO_TOLERANCE);
+ if (points_on_one_side == 0 || points_on_one_side == 3-points_on_line)
return false;
line_normal = ON_CrossProduct(plane_b.Normal(), intersect.Direction());
double dp4 = ON_DotProduct(TriB.A - intersect.from, line_normal);
double dp5 = ON_DotProduct(TriB.B - intersect.from, line_normal);
double dp6 = ON_DotProduct(TriB.C - intersect.from, line_normal);
- points_on_one_side = (dp4 >= -ON_ZERO_TOLERANCE) + (dp5 >=
-ON_ZERO_TOLERANCE) + (dp6 >= -ON_ZERO_TOLERANCE);
- if (points_on_one_side == 0 || points_on_one_side == 3)
+ points_on_line = ON_NearZero(dp4) + ON_NearZero(dp5) + ON_NearZero(dp6);
+ points_on_one_side = (dp4 >= ON_ZERO_TOLERANCE) + (dp5 >=
ON_ZERO_TOLERANCE) + (dp6 >= ON_ZERO_TOLERANCE);
+ if (points_on_one_side == 0 || points_on_one_side == 3-points_on_line)
return false;
double t[4];
int count = 0;
double t1, t2;
-
// dpi*dpj < 0 - the corresponding points are on different sides
// - the line segment between them are intersected by the plane-plane
// intersection line
This was sent by the SourceForge.net collaborative development platform, the
world's largest Open Source development site.
------------------------------------------------------------------------------
This SF.net email is sponsored by Windows:
Build for Windows Store.
http://p.sf.net/sfu/windows-dev2dev
_______________________________________________
BRL-CAD Source Commits mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/brlcad-commits
