public static bool IsPointInCircle(Vector2 point, Vector2 circleCentre, float circleRadius, bool trueOnEdge = true)
{
if (trueOnEdge)
{
return(Vector2Ext.DistanceBetweenTwoPoints(point, circleCentre) <= circleRadius);
}
else
{
return(Vector2Ext.DistanceBetweenTwoPoints(point, circleCentre) < circleRadius);
}
}
public void UpdateParamaters(Vector2 point0, Vector2 tangent0, Vector2 point1, Vector2 tangent1)
{
if (_p0 != null && _p1 != null && _t0 != null && _t1 != null)
{
//Only recompute arc if any of the paramaters have changed
if (Vector2Ext.Equality(_p0, point0) && Vector2Ext.Equality(_t0, tangent0) && Vector2Ext.Equality(_p1, point1) && Vector2Ext.Equality(_t1, tangent1))
{
return;
}
}
SetParams(point0, tangent0, point1, tangent1);
}
public AABB(Vector2 min, Vector2 max, int unused, bool validate = false) //Dirt!
{
if (validate)
{
if (Vector2Ext.Equality(min, max))
{
max.X += 1.0f;
max.Y += 1.0f;
}
if (max.X < min.X)
{
var s = max.X;
max.X = min.X;
min.X = s;
}
if (max.Y < min.Y)
{
var s = max.Y;
max.Y = min.Y;
min.Y = s;
}
}
Min = min;
Max = max;
Centre = 0.5f * (Min + Max);
Extents = 0.5f * (Max - Min);
Top = Max.Y;
Bottom = Min.Y;
Left = Min.X;
Right = Max.X;
Width = Right - Left;
Height = Top - Bottom;
}
private void ComputeArcs()
{
//Using Approach as detailed in: http://www.ryanjuckett.com/programming/biarc-interpolation/
_valid = false;
Arc0 = new Arc();
Arc1 = new Arc();
//Need to ensure tangents are normalised. Technique here is to renormalise and then check for if equal zero length (which happens if the normalise fails). Can replace with more robust / direct method later, if this becomes a concern
_t0 = _t0.Normal();
_t1 = _t1.Normal();
if (_t0.LengthSquared() == 0.0f || _t1.LengthSquared() == 0.0f)
{
return;
}
Vector2 v = _p1 - _p0;
//If points equal then no interpolation required
if (Vector2Ext.Equality(v, Vector2.Zero))
{
Arc0.Centre = _p0;
Arc0.Radius = 0.0f;
Arc0.Axis = v;
Arc0.Angle = 0.0f;
Arc0.ArcLength = 0.0f;
Arc1.Centre = _p1;
Arc1.Radius = 0.0f;
Arc1.Axis = v;
Arc1.Angle = 0.0f;
Arc1.ArcLength = 0.0f;
_valid = true;
return;
}
float pi = (float)Math.PI;
float vDotV = Vector2.Dot(v, v);
//We are using the approach that automatically picks the values of d, where d1 = d2
//The formula for deriving d2 is a quadratic
/*
* d2 = [ -(v.t) +/- sqrt((v.t)^2 + 2.(1 + t1.t2)(v.v)) ] / (2* (1 - t1.t2))
*/
//Compute denominator of the quadratic formula as it tells us if it is solvable or not (i.e. is it = 0)
Vector2 t = _t0 + _t1;
float vDotT = Vector2.Dot(v, t);
float t0DotT1 = Vector2.Dot(_t0, _t1);
float denominator = 2.0f * (1.0f - t0DotT1);
float d; //Set for those cases that do not return straight away with solution
//If quadratic formula denominator is zero. There are 2 cases here. In both cases the tangents are equal. In one the vector between the two curve points are perpendicular to them
if (denominator == 0.0f)
{
float vDotT1 = Vector2.Dot(v, _t1);
if ((float)Math.Abs(vDotT1) == 0.0f)
{
//Tangents are equal to each other AND perpendicular to p0 and p1. The solution is two equal semi-circles
float vMag = v.Length();
float radius = 0.25f * vMag;
Vector2 quarterV = 0.25f * v;
Vector2 pm = _p0 + (2.0f * quarterV);
float vCrossT1 = (v.X * _t1.Y) - (v.Y * _t1.X);
Arc0.Centre = _p0 + quarterV;
Arc0.Radius = radius;
Arc0.Axis = _p0 - Arc0.Centre;
Arc0.Angle = vCrossT1 > 0.0f ? pi : -pi; //Need to check this > or <. standard is < then > but doesn't seem to work...
Arc0.ArcLength = pi * radius;
Arc1.Centre = _p0 + (3.0f * quarterV);
Arc1.Radius = radius;
Arc1.Axis = _p1 - Arc1.Centre;
Arc1.Angle = vCrossT1 > 0.0f ? pi : -pi;
Arc1.ArcLength = pi * radius;
_valid = true;
return;
}
else
{
//The Tangents are equal to each other (this is the only route through where d can be negative)
d = vDotV / (4.0f * vDotT1);
}
}
else
{
//Standard result, we use the positive version of the quadratic formula to calculate d
float discriminant = (vDotT * vDotT) + (denominator * vDotV);
d = (-vDotT + (float)Math.Sqrt(discriminant)) / denominator;
}
//At this stage we have either calculated the value of d (d1 = d2), or we have set the two arcs appropriately for special cases
//Calculate the mid point
//pm=p1+p2+d2(t1−t2)/2
Vector2 mid = 0.5f * (_p0 + _p1 + (d * (_t0 - _t1)));
//Caclulate Vectors from the curve points to the mid point
Vector2 p0ToMid = mid - _p0;
Vector2 p1ToMid = mid - _p1;
//Calculate Arc Centre, Radius and Angle values
Arc0 = ComputeSingleArc(_p0, _t0, p0ToMid);
Arc1 = ComputeSingleArc(_p1, _t1, p1ToMid);
if (d < 0.0f)
{
//Use longer path around if d is negative (doesn't seem to work right yet)
/*
* float arc0mul = 2.0f * pi;
* arc0mul *= _arc0.Angle >= 0.0f ? 1.0f : -1.0f;
* _arc0.Angle = arc0mul - _arc0.Angle;
*
* float arc1mul = 2.0f * pi;
* arc1mul *= _arc1.Angle >= 0.0f ? 1.0f : -1.0f;
* _arc1.Angle = arc1mul - _arc1.Angle;
*/
}
//Ignoring the code to check for negative d in the example, as surely should always be positive (i.e. we are taking the shorter parth around the circles)
Arc0.Axis = _p0 - Arc0.Centre;
Arc1.Axis = _p1 - Arc1.Centre;
Arc0.ArcLength = Arc0.Radius == 0.0f ? p0ToMid.Length() : (float)Math.Abs(Arc0.Radius * Arc0.Angle);
Arc1.ArcLength = Arc1.Radius == 0.0f ? p1ToMid.Length() : (float)Math.Abs(Arc1.Radius * Arc1.Angle);
_valid = true;
}
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));
}
