bool PointOnSegment(Vertex A, Vertex B,
Vertex P,
float distanceEpsilon,
float parametricEpsilon,
out float pointSegmentDistance)
{
// Determines whether P lies within the segment A-B
float segmentLength = Vertex.Distance(A, B);
float tangentABdist = Vertex.Dot(Vertex.Normalize(B - A), Vertex.Normalize(P - A)) * (P - A).Length();
float u = tangentABdist / segmentLength;
if (u < parametricEpsilon || u > 1.0 - parametricEpsilon)
{
pointSegmentDistance = float.MaxValue;
return(false);
}
Vertex isect = A + (B - A) * u;
float dist = (P - isect).Length();
pointSegmentDistance = dist;
if (dist > distanceEpsilon * segmentLength)
{
return(false);
}
return(true);
}
float ClosestAngleOnTri(int vA, int vB, int vC)
{
int[] indices = new int[3];
indices[0] = vA;
indices[1] = vB;
indices[2] = vC;
double closestAngle = Math.PI;
for (int i = 0; i < 3; i++)
{
Vertex nAB = Vertex.Normalize(vertices[indices[(i + 1) % 3]] - vertices[indices[i]]);
Vertex nAC = Vertex.Normalize(vertices[indices[(i + 2) % 3]] - vertices[indices[i]]);
float dot = Vertex.Dot(nAB, nAC);
Debug.Assert(dot >= -1.01f && dot <= 1.01f);
double angle = Math.Acos(dot);
if (angle < closestAngle)
{
closestAngle = angle;
}
}
return((float)closestAngle);
}