public void getUV(V3 P, out float u, out float v)
{
V3 AB = B - A;
V3 AC = C - A;
V3 AP = P - A;
//alfa
u = V3.prod_scal(ref AP, ref AB) / AB.Norme2();
//beta
V3 aux = AP - u * AB;
v = V3.prod_scal(ref aux, ref AC) / AC.Norme2();
}
public bool intersection_RayObject(V3 R0, V3 Rd, out V3 P, out V3 N, out float t)
{
V3 CR0;
float A, B, C, delta, t1, t2;
P = new V3(0, 0, 0);
N = new V3(0, 0, 0);
t = -1;
CR0 = R0 - Center;
// (t^2) rd^2 + 2*t*rd*b +b^2 = R^2
A = Rd.Norme2();
B = 2f * V3.prod_scal(ref Rd, ref CR0);
C = CR0.Norme2() - (R * R);
delta = (B * B) - (4 * A * C);
if (delta < 0)
{
return(false);
}
t1 = (-B + (float)Math.Sqrt(delta)) / (2 * A);
t2 = (-B - (float)Math.Sqrt(delta)) / (2 * A);
t = (t1 > 0 && t1 < t2) ? t1 : t2;
if (t < MIN_DISTANCE)
{
return(false);
}
P = R0 + t * Rd;
N = getPixelSphereNormal(P);
return(true);
}
public override bool testColition(V3 positionStart, V3 direction, out double TPositionColition)
{
// need aproximation to calculate float
// calculate the aproximation
double a;
double b;
double c;
a = (direction.Norme2());
b = 2 * direction * (positionStart - this.getPosition());
c = (positionStart - this.getPosition()).Norme2() - (this.rayon * this.rayon);
// calcul alpha = B²-4ac
double alpha = (b * b) - (4 * a * c);
// 0 result no colition alpha = 0
if (alpha < 0)
{
TPositionColition = 0;
return(false);
}
// 1 colition tangante
if (alpha == 0)
{
TPositionColition = (-b) / (2 * a);
return(true);
}
// 2 colition
if (alpha > 0)
{
//Console.WriteLine("alpha");
double t2 = (-b + Math.Sqrt(alpha)) / (2 * a);
double t1 = (-b - Math.Sqrt(alpha)) / (2 * a);
if (0 < t1 && t1 < t2)
{
TPositionColition = t1;
return(true);
}
if (t1 < 0 && 0 < t2)
{
TPositionColition = t2;
return(true);
}
if (t1 < 0 && t2 < 0)
{
TPositionColition = 0;
return(false);
}
}
TPositionColition = 0;
return(false);
}
public override float getIntersect(V3 R, V3 cam)
{
float t, t1, t2;
float A = R.Norme2();
float B = 2*(R.x * (cam.x - origin.x) + R.y * (cam.y - origin.y) + R.z * (cam.z - origin.z));
float C = (cam.x - origin.x) * (cam.x - origin.x) + (cam.y - origin.y) * (cam.y - origin.y) + (cam.z - origin.z) * (cam.z - origin.z) - (this.rayon * this.rayon);
float D = B * B - 4 * A * C;
if (D < 0)
{
return -1f;
}
else
{
t = -1f;
if (D > 0)
{
t1 = (-B - IMA.Sqrtf(D)) / (2 * A);
t2 = (-B + IMA.Sqrtf(D)) / (2 * A);
if (t1 < t2 && t1 >= 0)
{
t = t1;
}
else if (t2 < t1 && t2 >= 0)
{
t = t2;
}
}
else
{
t = -B / (2 * A);
}
return t;
}
}
