private bool ProcessHits(
double t1, double t2,
double tmin, double tmax,
ref RayHit3d hit)
{
if (t1 >= tmin)
{
if (t1 < tmax && t1 < hit.T)
{
hit.T = t1;
hit.Point = GetPointOnRay(t1);
hit.Coord = V2d.NaN;
hit.BackSide = false;
return(true);
}
return(false);
}
if (t2 >= tmin)
{
if (t2 < tmax && t2 < hit.T)
{
hit.T = t2;
hit.Point = GetPointOnRay(t2);
hit.Coord = V2d.NaN;
hit.BackSide = true;
return(true);
}
}
return(false);
}
/// <summary>
/// Returns true if the ray hits the sphere given by center and
/// radius within the supplied parameter interval and before the
/// parameter value contained in the supplied hit. Note that a
/// hit is only registered if the front or the backsurface is
/// encountered within the interval.
/// </summary>
public bool HitsSphere(
V3d center, double radius,
double tmin, double tmax,
ref RayHit3d hit)
{
V3d originSubCenter = Origin - center;
double a = Direction.LengthSquared;
double b = Direction.Dot(originSubCenter);
double c = originSubCenter.LengthSquared - radius * radius;
// --------------------- quadric equation : a t^2 + 2b t + c = 0
double d = b * b - a * c; // factor 2 was eliminated
if (d < Constant <double> .PositiveTinyValue) // no root ?
{
return(false); // then exit
}
if (b > 0.0) // stable way to calculate
{
d = -Fun.Sqrt(d) - b; // the roots of a quadratic
}
else // equation
{
d = Fun.Sqrt(d) - b;
}
double t1 = d / a;
double t2 = c / d; // Vieta : t1 * t2 == c/a
return(t1 < t2
? ProcessHits(t1, t2, tmin, tmax, ref hit)
: ProcessHits(t2, t1, tmin, tmax, ref hit));
}
public bool HitsCircle(Circle3d circle, double tmin, double tmax, ref RayHit3d hit)
{
var dc = circle.Normal.Dot(Direction);
var dw = circle.Normal.Dot(circle.Center - Origin);
// If parallel to plane
if (dc == 0.0)
{
return(false);
}
var t = dw / dc;
if (!ComputeHit(t, tmin, tmax, ref hit))
{
return(false);
}
if (V3d.Distance(hit.Point, circle.Center) > circle.Radius)
{
hit.Point = V3d.NaN;
hit.T = tmax;
return(false);
}
return(true);
}
/// <summary>
/// Returns true if the ray hits the quad before the parameter
/// value contained in the supplied hit. Detailed information about
/// the hit is returned in the supplied hit. In order to obtain all
/// potential hits, the supplied hit can be initialized with
/// RayHit3d.MaxRange.
/// </summary>
public bool Hits(
Quad3d quad, ref RayHit3d hit
)
{
return(HitsQuad(quad.P0, quad.P1, quad.P2, quad.P3,
double.MinValue, double.MaxValue, ref hit));
}
/// <summary>
/// Returns true if the ray hits the supplied sphere within the
/// supplied parameter interval and before the parameter value
/// contained in the supplied hit. Note that a hit is only
/// registered if the front or the backsurface is encountered
/// within the interval.
/// </summary>
public bool Hits(
Sphere3d sphere,
double tmin, double tmax,
ref RayHit3d hit)
{
return(HitsSphere(sphere.Center, sphere.Radius, tmin, tmax, ref hit));
}
/// <summary>
/// Returns true if the ray hits the triangle before the parameter
/// value contained in the supplied hit. Detailed information about
/// the hit is returned in the supplied hit.
/// </summary>
public bool Hits(
Triangle3d triangle, ref RayHit3d hit
)
{
return(HitsTrianglePointAndEdges(
triangle.P0, triangle.Edge01, triangle.Edge02,
double.MinValue, double.MaxValue, ref hit));
}
/// <summary>
/// Returns true if the ray hits the other ray before the parameter
/// value contained in the supplied hit. Detailed information about
/// the hit is returned in the supplied hit.
/// </summary>
public bool Hits(
Ray3d ray,
double tmin, double tmax,
ref RayHit3d hit
)
{
return(HitsRay(ray, tmin, tmax, ref hit));
}
private bool GetClosestHit(
double t1, double t2,
double tmin, double tmax,
ref RayHit3d hit)
{
return(t1 < t2
? ProcessHits(t1, t2, tmin, tmax, ref hit)
: ProcessHits(t2, t1, tmin, tmax, ref hit));
}
/// <summary>
/// Returns true if the ray hits the quad within the supplied
/// parameter interval and before the parameter value contained
/// in the supplied hit. Detailed information about the hit is
/// returned in the supplied hit. In order to obtain all potential
/// hits, the supplied hit can be initialized with RayHit3d.MaxRange.
/// </summary>
public bool Hits(
Quad3d quad,
double tmin, double tmax,
ref RayHit3d hit
)
{
return(HitsQuad(quad.P0, quad.P1, quad.P2, quad.P3,
tmin, tmax, ref hit));
}
public bool Hits(
Cylinder3d cylinder,
double tmin, double tmax,
ref RayHit3d hit)
{
var intersects = HitsCylinder(cylinder, tmin, tmax, ref hit);
return(intersects);
}
/// <summary>
/// Returns true if the ray hits the triangle within the supplied
/// parameter interval and before the parameter value contained
/// in the supplied hit. Detailed information about the hit is
/// returned in the supplied hit. In order to obtain all potential
/// hits, the supplied hit can be initialized with RayHit3d.MaxRange.
/// </summary>
public bool Hits(
Triangle3d triangle,
double tmin, double tmax,
ref RayHit3d hit
)
{
return(HitsTrianglePointAndEdges(
triangle.P0, triangle.Edge01, triangle.Edge02,
tmin, tmax, ref hit));
}
/// <summary>
/// Returns true if the ray hits the other ray before the parameter
/// value contained in the supplied hit. Detailed information about
/// the hit is returned in the supplied hit.
/// </summary>
public bool HitsRay(
Ray3d ray,
double tmin, double tmax,
ref RayHit3d hit
)
{
V3d d = Origin - ray.Origin;
V3d u = Direction;
V3d v = ray.Direction;
V3d n = u.Cross(v);
if (Fun.IsTiny(d.Length))
{
return(true);
}
else if (Fun.IsTiny(u.Cross(v).Length))
{
return(false);
}
else
{
//-t0*u + t1*v + t2*n == d
//M = {-u,v,n}
//M*{t0,t1,t2}T == d
//{t0,t1,t2}T == M^-1 * d
M33d M = new M33d();
M.C0 = -u;
M.C1 = v;
M.C2 = n;
if (M.Invertible)
{
V3d t = M.Inverse * d;
if (Fun.IsTiny(t.Z))
{
ProcessHits(t.X, double.MaxValue, tmin, tmax, ref hit);
return(true);
}
else
{
return(false);
}
}
else
{
return(false);
}
}
}
public bool HitsPlane(Plane3d plane, double tmin, double tmax, ref RayHit3d hit)
{
var dc = plane.Normal.Dot(Direction);
var dw = plane.Distance - plane.Normal.Dot(Origin);
// If parallel to plane
if (dc == 0.0)
{
return(false);
}
var t = dw / dc;
return(ComputeHit(t, tmin, tmax, ref hit));
}
/// <summary>
/// Returns true if the ray hits the triangle within the supplied
/// parameter interval and before the parameter value contained
/// in the supplied hit. Detailed information about the hit is
/// returned in the supplied hit. In order to obtain all potential
/// hits, the supplied hit can be initialized with RayHit3d.MaxRange.
/// </summary>
public bool HitsTriangle(
V3d p0, V3d p1, V3d p2,
double tmin, double tmax,
ref RayHit3d hit
)
{
V3d edge01 = p1 - p0;
V3d edge02 = p2 - p0;
V3d plane = V3d.Cross(Direction, edge02);
double det = V3d.Dot(edge01, plane);
if (det > -0.0000001 && det < 0.0000001)
{
return(false);
}
// ray ~= paralell / Triangle
V3d tv = Origin - p0;
det = 1.0 / det; // det is now inverse det
double u = V3d.Dot(tv, plane) * det;
if (u < 0.0 || u > 1.0)
{
return(false);
}
plane = V3d.Cross(tv, edge01); // plane is now qv
double v = V3d.Dot(Direction, plane) * det;
if (v < 0.0 || u + v > 1.0)
{
return(false);
}
double t = V3d.Dot(edge02, plane) * det;
if (t < tmin || t >= tmax || t >= hit.T)
{
return(false);
}
hit.T = t;
hit.Point = Origin + t * Direction;
hit.Coord.X = u; hit.Coord.Y = v;
hit.BackSide = (det < 0.0);
return(true);
}
private bool ComputeHit(
double t,
double tmin, double tmax,
ref RayHit3d hit)
{
if (t >= tmin)
{
if (t < tmax && t < hit.T)
{
hit.T = t;
hit.Point = GetPointOnRay(t);
hit.Coord = V2d.NaN;
hit.BackSide = false;
return(true);
}
return(false);
}
return(false);
}
/// <summary>
/// Returns true if the ray hits the quad within the supplied
/// parameter interval and before the parameter value contained
/// in the supplied hit. The quad is considered to consist of the
/// two triangles [p0,p1,p2] and [p0,p2,p3]. Detailed information
/// about the hit is returned in the supplied hit. In order to obtain
/// all potential hits, the supplied hit can be initialized with
/// RayHit3d.MaxRange.
/// </summary>
public bool HitsQuad(
V3d p0, V3d p1, V3d p2, V3d p3,
double tmin, double tmax,
ref RayHit3d hit
)
{
V3d e02 = p2 - p0;
bool result = false;
if (HitsTrianglePointAndEdges(p0, p1 - p0, e02, tmin, tmax,
ref hit))
{
hit.Coord.X += hit.Coord.Y;
result = true;
}
if (HitsTrianglePointAndEdges(p0, e02, p3 - p0, tmin, tmax,
ref hit))
{
hit.Coord.Y += hit.Coord.X;
result = true;
}
return(result);
}
/// <summary> /// Returns true if the ray hits the other ray before the parameter /// value contained in the supplied hit. Detailed information about /// the hit is returned in the supplied hit. /// </summary> public bool Hits(Ray3d ray, ref RayHit3d hit) => HitsRay(ray, double.MinValue, double.MaxValue, ref hit);
/// <summary>
/// Returns true if the ray hits the other ray before the parameter
/// value contained in the supplied hit. Detailed information about
/// the hit is returned in the supplied hit.
/// </summary>
public bool Hits(
Ray3d ray, ref RayHit3d hit
)
{
return(HitsRay(ray, double.MinValue, double.MaxValue, ref hit));
}
public bool HitsCylinder(Cylinder3d cylinder,
double tmin, double tmax,
ref RayHit3d hit)
{
var axisDir = cylinder.Axis.Direction.Normalized;
// Vector Cyl.P0 -> Ray.Origin
var op = Origin - cylinder.P0;
// normal RayDirection - CylinderAxis
var normal = Direction.Cross(axisDir);
var unitNormal = normal.Normalized;
// normal (Vec Cyl.P0 -> Ray.Origin) - CylinderAxis
var normal2 = op.Cross(axisDir);
var t = -normal2.Dot(unitNormal) / normal.Length;
var radius = cylinder.Radius;
if (cylinder.DistanceScale != 0)
{ // cylinder gets bigger, the further away it is
var pnt = GetPointOnRay(t);
var dis = V3d.Distance(pnt, this.Origin);
radius = ((cylinder.Radius / cylinder.DistanceScale) * dis) * 2;
}
// between enitre rays (caps are ignored)
var shortestDistance = Fun.Abs(op.Dot(unitNormal));
if (shortestDistance <= radius)
{
var s = Fun.Abs(Fun.Sqrt(radius.Square() - shortestDistance.Square()) / Direction.Length);
var t1 = t - s; // first hit of Cylinder shell
var t2 = t + s; // second hit of Cylinder shell
if (t1 > tmin && t1 < tmax)
{
tmin = t1;
}
if (t2 < tmax && t2 > tmin)
{
tmax = t2;
}
hit.T = t1;
hit.Point = GetPointOnRay(t1);
// check if found point is outside of Cylinder Caps
var bottomPlane = new Plane3d(cylinder.Circle0.Normal, cylinder.Circle0.Center);
var topPlane = new Plane3d(cylinder.Circle1.Normal, cylinder.Circle1.Center);
var heightBottom = bottomPlane.Height(hit.Point);
var heightTop = topPlane.Height(hit.Point);
// t1 lies outside of caps => find closest cap hit
if (heightBottom > 0 || heightTop > 0)
{
hit.T = tmax;
// intersect with bottom Cylinder Cap
var bottomHit = HitsPlane(bottomPlane, tmin, tmax, ref hit);
// intersect with top Cylinder Cap
var topHit = HitsPlane(topPlane, tmin, tmax, ref hit);
// hit still close enough to cylinder axis?
var distance = cylinder.Axis.Ray3d.GetMinimalDistanceTo(hit.Point);
if (distance <= radius && (bottomHit || topHit))
{
return(true);
}
}
else
{
return(true);
}
}
hit.T = tmax;
hit.Point = V3d.NaN;
return(false);
}
/// <summary> /// Returns true if the ray hits the other ray before the parameter /// value contained in the supplied hit. Detailed information about /// the hit is returned in the supplied hit. /// </summary> public bool Hits(Ray3d ray, double tmin, double tmax, ref RayHit3d hit) => HitsRay(ray, tmin, tmax, ref hit);
