public double getT(Ray r, RenderObject o) {
Matrix m = new Matrix();
double[][] u = r.u3;
double[][] ut = m.tMatrix(u);
double[][] p = r.p0C.subtract(r.p0C, o.getOrigin()).toArray3D();
double[][] pt = m.tMatrix(p);
double[][] aa = m.multiplyMatrix(ut, u);
double a = aa[0][0];
double bb[][] = m.multiplyMatrix(ut, p);
double b = bb[0][0] * 2;
double cc[][] = m.multiplyMatrix(pt, p);
double cee = cc[0][0] - (o.getRadius() * o.getRadius());
double existance = (b * b) - (4 * a * cee);
if (existance < 0) {
return -1;
} else {
double t1 = ((-1 * b) + Math.sqrt(existance)) / (2 * a);
double t2 = ((-1 * b) - Math.sqrt(existance)) / (2 * a);
if (t1 < 0 && t2 < 0) {
return -1;
} else if (t1 < 0) {
return t2;
} else if (t2 < 0) {
return t1;
} else {
return Math.min(t1, t2);
}
}
}
