public override void trace(Ray r)
{
vect3d dst = r.pos - this.pos;
double B = dst * r.dir;
double C = dst.length2() - this.radius2;
double D = B * B - C;
if (D > 0)
{
double dist;
double flip_norm = 1;
if (r.is_outside)
{
dist = -B - Math.Sqrt(D);
}
else
{
dist = -B + Math.Sqrt(D);
flip_norm = -1;
}
if (dist > 0 && dist < r.hit_dist)
{
r.hit_dist = dist;
r.hit_pos = r.pos + r.dir * dist;
r.hit_norm = (r.hit_pos - this.pos) * flip_norm;
r.hit_norm.normalize();
r.hit_tex_coord = r.hit_norm;
r.hit_object = this;
}
}
}
protected void lightDirectPointSpecNoShadow(Ray r, double specular_coeff, ref vect3d diff_accum, ref vect3d spec_accum)
{
Ray shadow_ray = new Ray();
shadow_ray.pos = r.hit_pos;
foreach (var l in r.scene.lights)
{
vect3d dir = l.pos - r.hit_pos;
double dist2 = 1.0 / dir.length2();
dir *= Math.Sqrt(dist2);
// diffuse
double incidence_dif = (dir * r.hit_norm);
if (incidence_dif > 0)
{
diff_accum += l.color * incidence_dif * dist2;
}
// specular highlight
vect3d dir_r = r.hit_norm * ((dir * r.hit_norm) * 2) - dir;
double incidence_spec = (dir_r * r.hit_norm);
if (incidence_spec > 0)
{
spec_accum += l.color * Math.Pow(incidence_spec, specular_coeff) * dist2;
}
}
}
public static vect3d rand_in_sphere()
{
vect3d p;
do
{
p = new vect3d(rand.NextDouble() * 2 - 1, rand.NextDouble() * 2 - 1, rand.NextDouble() * 2 - 1);
} while (p.length2() > 1);
return(p);
}
protected void lightDirectPointSpec(Ray r, double specular_coeff, ref vect3d diff_accum, ref vect3d spec_accum)
{
Ray shadow_ray = new Ray();
shadow_ray.pos = r.hit_pos;
foreach (var l in r.scene.lights)
{
vect3d dir = l.pos - r.hit_pos;
double dist2 = dir.length2();
double dist2_inv = 1.0 / dist2;
dir *= Math.Sqrt(dist2_inv);
// calculate incidences to do early reject of shadow ray
double incidence_dif = (dir * r.hit_norm);
vect3d dir_r = r.hit_norm * ((dir * r.hit_norm) * 2) - dir;
double incidence_spec = (dir_r * r.hit_norm);
if (incidence_dif < 0 && incidence_spec < 0)
{
continue;
}
// shadow ray test
shadow_ray.dir = dir;
shadow_ray.hit_dist = Double.MaxValue;
r.scene.trace(shadow_ray);
if (shadow_ray.hit_dist * shadow_ray.hit_dist < dist2)
{
continue;
}
// diffuse
if (incidence_dif > 0)
{
diff_accum += l.color * incidence_dif * dist2_inv;
}
// specular highlight
if (incidence_spec > 0)
{
spec_accum += l.color * Math.Pow(incidence_spec, specular_coeff) * dist2_inv;
}
}
}
