public static bool IsPointOnLineSegment(Vector2 p, Vector2 v0, Vector2 v1)
{
var vp = p - v0;
var l = v1 - v0;
if (Vector2Ext.Equality(vp, Vector2Ext.Zero))
{
return(true); //p == v0
}
var vpNormal = vp.Normal();
var lNormal = l.Normal();
if ((float)Math.Abs((double)Vector2Ext.Dot(vpNormal, lNormal)) < OneMinusEps)
{
return(false);
}
//Lines are the same, are they within the length
if (vp.Length() <= l.Length())
{
return(true);
}
return(false);
}
public static LineIntersectionResult RobustLineIntersectAndResult(Vector2 a0, Vector2 a1, Vector2 b0, Vector2 b1, bool fireOnOverlap = true)
{
//Fail on zero length lines
if (Vector2Ext.Equality(a0, a1) || Vector2Ext.Equality(b0, b1))
{
return new LineIntersectionResult()
{
Intersecting = false,
CoLinear = false,
IntersectPoint = Vector2.Zero
}
}
;
var r = a1 - a0;
var s = b1 - b0;
var qMp = b0 - a0;
float rXs = Vector2Ext.Cross(r, s);
float qMpXr = Vector2Ext.Cross(qMp, r);
//1. Colinear Check
if (IsFuzzyZero(rXs) && IsFuzzyZero(qMpXr))
{
//They are colinear
if (fireOnOverlap)
{
float qMpDOTr = Vector2Ext.Dot(qMp, r);
float rDOTr = Vector2Ext.Dot(r, r);
var pMq = a0 - b0;
float pMqDOTs = Vector2Ext.Dot(pMq, s);
float sDOTs = Vector2Ext.Dot(s, s);
if ((qMpDOTr >= 0.0f && qMpDOTr <= rDOTr) || (pMqDOTs >= 0.0f && pMqDOTs <= sDOTs))
{
//You do not get provided a valid intersect point as the lines lie on top of each other
return(new LineIntersectionResult()
{
Intersecting = true,
CoLinear = true,
IntersectPoint = Vector2.Zero
});
}
}
//Not classifying overlap as intersection
return(new LineIntersectionResult()
{
Intersecting = false,
CoLinear = true,
IntersectPoint = Vector2.Zero
});
}
//2. Paralell - Do not intersect
if (IsFuzzyZero(rXs) && !IsFuzzyZero(qMpXr))
{
return(new LineIntersectionResult()
{
Intersecting = false,
CoLinear = false,
IntersectPoint = Vector2.Zero
});
}
//3.Intersect at Single Point
float t = Vector2Ext.Cross(qMp, s) / rXs;
float u = Vector2Ext.Cross(qMp, r) / rXs;
if (!IsFuzzyZero(rXs) && t >= 0.0f && t <= 1.0f && u >= 0.0f && u <= 1.0f)
{
return(new LineIntersectionResult()
{
Intersecting = true,
CoLinear = false,
IntersectPoint = a0 + (r * t)
});
}
//4. Do not intersect
return(new LineIntersectionResult()
{
Intersecting = false,
CoLinear = false,
IntersectPoint = Vector2.Zero
});
}
public static float DotWith(this Vector2 v0, Vector2 v1)
{
return(Vector2Ext.Dot(v0, v1));
}