/**
* Test if a given 2D point (x, y) is inside a triangle of this TIN (given
* by index). If so, return true and give the elevation value by reference.
*/
bool vtTin::TestTriangle(int tri, const DPoint2 &p, float &fAltitude) const
{
// get points
const int v0 = m_tri[tri*3];
const int v1 = m_tri[tri*3+1];
const int v2 = m_tri[tri*3+2];
const DPoint2 &p1 = m_vert[v0];
const DPoint2 &p2 = m_vert[v1];
const DPoint2 &p3 = m_vert[v2];
// First try to identify which triangle
if (PointInTriangle(p, p1, p2, p3))
{
double bary[3];
if (BarycentricCoords(p1, p2, p3, p, bary))
{
// compute barycentric combination of function values at vertices
const double val = bary[0] * m_z[v0] +
bary[1] * m_z[v1] +
bary[2] * m_z[v2];
fAltitude = (float) val;
return true;
}
}
return false;
}
// Returns true iff the point is inside or on the exterior of the triangle and not equal to one of the triangle vertices.
bool point_triangle_intersection(ofVec3f &t1, ofVec3f &t2, ofVec3f &t3, ofVec3f &point)
{
if(point == t1 || point == t2 || point == t3)
{
return false;
}
float c1, c2, c3;
BarycentricCoords(t1, t2, t3, point, c1, c2, c3);
if(0 < c1 && c1 < 1 &&
0 < c2 && c2 < 1 &&
0 < c3 && c3 < 1)
{
return true;
}
}
