00001 #include "sysdep.h"
00002 #include "mytritri.h"
00003
00004 Vector3D my_tri_tri_intersect(const Triangle& t1, const Triangle& t2)
00005 {
00006 Plane p1(t1.v1,t1.v2,t1.v3);
00007 int other_side=0;
00008 {
00009 float f1=p1.Classify(t2.v1);
00010 float f2=p1.Classify(t2.v2);
00011 float f3=p1.Classify(t2.v3);
00012 float f12=f1*f2;
00013 float f23=f2*f3;
00014 if (f12>0.0f && f23>0.0f) return Vector3D::Zero;
00015 other_side=(f12<0.0f?(f23<0.0f?1:0):2);
00016 }
00017 Plane p2(t2.v1,t2.v2,t2.v3);
00018 Vector3D n12(p1.normal+p2.normal);
00019 TriangleDesc td2(t2,p2);
00020 const Vector3D& a2=td2[other_side+1];
00021 const Vector3D& b2=td2[other_side];
00022 const Vector3D& c2=td2[other_side+2];
00023 float t21=-(p1.d+p2.d+a2*n12)/((b2-a2)*n12);
00024 TriangleDesc td1(t1,p1);
00025 Vector3D P21(a2+t21*(b2-a2));
00026 if (td1.pointInTri(P21)) return P21;
00027 float t22=-(p1.d+p2.d+c2*n12)/((b2-c2)*n12);
00028 Vector3D P22(c2+t22*(b2-c2));
00029 if (td1.pointInTri(P22)) return P22;
00030
00031 {
00032 float f1=p2.Classify(t1.v1);
00033 float f2=p2.Classify(t1.v2);
00034 float f3=p2.Classify(t1.v3);
00035 float f12=f1*f2;
00036 float f23=f2*f3;
00037 if (f12>0.0f && f23>0.0f) return Vector3D::Zero;
00038 other_side=(f12<0.0f?(f23<0.0f?1:0):2);
00039 }
00040 const Vector3D& a1=td1[other_side+1];
00041 const Vector3D& b1=td1[other_side];
00042 const Vector3D& c1=td1[other_side+2];
00043 float t11=-(p1.d+p2.d+a1*n12)/((b1-a1)*n12);
00044 Vector3D P11(a1+t11*(b1-a1));
00045 if (td2.pointInTri(P11)) return P11;
00046 float t12=-(p1.d+p2.d+c1*n12)/((b1-c1)*n12);
00047 Vector3D P12(c1+t12*(b1-c1));
00048 if (td2.pointInTri(P12)) return P12;
00049 return Vector3D::Zero;
00050 }
