public override Vect3 GetNormalAt(Vect3 hitPoint)
{
Vect3 tmp = hitPoint - Position;
Vect3 tmp2 = tmp.CrossProduct(LookAt);
return(tmp.CrossProduct(tmp2).Normalize());
}
private Color GetTextureColorAt(Vect3 hitPoint)
{
// calculate x (longitude)
Vect3 tmp = (hitPoint - Position).Normalize();
double y = System.Math.Acos(tmp * LookAt) / System.Math.PI;
// project to equator plane
double dist = -(tmp * LookAt);
tmp = (tmp + LookAt * dist).Normalize();
double x = System.Math.Acos(tmp * RotVect) / (2 * System.Math.PI);
tmp = tmp.CrossProduct(RotVect);
if (tmp * LookAt < 0)
{
x = 0.5 + x;
}
else
{
x = 0.5 - x;
}
return(_texture.GetColorAt(x, y));
}
public override void Rotate(Matrix4 rotationMatrix)
{
EdgeV1V2 = VectMatrix.Multiply(EdgeV1V2, rotationMatrix);
EdgeV1V3 = VectMatrix.Multiply(EdgeV1V3, rotationMatrix);
LookAt = EdgeV1V2.CrossProduct(EdgeV1V3);
}
public override bool Contains(Vect3 hitPoint)
{
Vect3 tmp = hitPoint - Position;
Vect3 temp3 = EdgeV1V2.CrossProduct(EdgeV1V3);
if (System.Math.Abs(temp3 * tmp) > Constants.EPS)
{
return(false);
}
double uu = EdgeV1V2 * EdgeV1V2;
double uv = EdgeV1V2 * EdgeV1V3;
double vv = EdgeV1V3 * EdgeV1V3;
double wu = EdgeV1V2 * tmp;
double wv = EdgeV1V3 * tmp;
double d = uv * uv - uu * vv;
double s = (uv * wv - vv * wu) / d;
if (s < 0 || s > 1)
{
return(false);
}
double t = (uv * wu - uu * wv) / d;
if (t < 0 || s + t > 1)
{
return(false);
}
return(true);
}
public Triangle(Vect3 v1, Vect3 v2, Vect3 v3, Color color)
: base(v1, new Vect3())
{
Color = color;
V2 = v2;
V3 = v3;
EdgeV1V2 = v2 - v1;
EdgeV1V3 = v3 - v1;
LookAt = EdgeV1V2.CrossProduct(EdgeV1V3).Normalize();
}
public Sphere(Vect3 position, Vect3 lookAt, double rotationRad, Color color) : base(position, lookAt)
{
Color = color;
Radius = lookAt.Length();
// calculate the rotation of the 0-meridian
RotVect = lookAt;
// check so we don't end up with two linear dependent vectors
if (System.Math.Abs(RotVect.Y) > Constants.EPS &&
System.Math.Abs(RotVect.X) < Constants.EPS &&
System.Math.Abs(RotVect.Z) < Constants.EPS)
{
RotVect.X += 1;
}
else
{
RotVect.Y += 1;
}
RotVect = RotVect.CrossProduct(lookAt).Normalize();
LookAt = LookAt.Normalize();
Rotate(lookAt, rotationRad);
}
