public function intersect($ray)
{
$info = new RayTracer_IntersectionInfo();
$Vd = $this->position->dot($ray->direction);
if ($Vd == 0) {
return $info;
}
// no intersection
$t = -($this->position->dot($ray->position) + $this->d) / $Vd;
if ($t <= 0) {
return $info;
}
$info->shape = $this;
$info->isHit = true;
$info->position = RayTracer_Vector::add($ray->position, RayTracer_Vector::multiplyScalar($ray->direction, $t));
$info->normal = $this->position;
$info->distance = $t;
if ($this->material->hasTexture) {
$vU = new RayTracer_Vector($this->position->y, $this->position->z, -$this->position->x);
$vV = $vU->cross($this->position);
$u = $info->position->dot($vU);
$v = $info->position->dot($vV);
$info->color = $this->material->getColor($u, $v);
} else {
$info->color = $this->material->getColor(0, 0);
}
return $info;
}
public function getRay($vx, $vy)
{
$pos = RayTracer_Vector::subtract($this->screen, RayTracer_Vector::subtract(RayTracer_Vector::multiplyScalar($this->equator, $vx), RayTracer_Vector::multiplyScalar($this->up, $vy)));
$pos->y = $pos->y * -1;
$dir = RayTracer_Vector::subtract($pos, $this->position);
$ray = new RayTracer_Ray($pos, $dir->normalize());
return $ray;
}
public function intersect($ray)
{
$info = new RayTracer_IntersectionInfo();
$info->shape = $this;
$dst = RayTracer_Vector::subtract($ray->position, $this->position);
$B = $dst->dot($ray->direction);
$C = $dst->dot($dst) - $this->radius * $this->radius;
$D = $B * $B - $C;
if ($D > 0) {
// intersection!
$info->isHit = true;
$info->distance = -$B - sqrt($D);
$info->position = RayTracer_Vector::add($ray->position, RayTracer_Vector::multiplyScalar($ray->direction, $info->distance));
$info->normal = RayTracer_Vector::subtract($info->position, $this->position)->normalize();
$info->color = $this->material->getColor(0, 0);
} else {
$info->isHit = false;
}
return $info;
}
public function getReflectionRay($P, $N, $V)
{
$c1 = -$N->dot($V);
$R1 = RayTracer_Vector::add(RayTracer_Vector::multiplyScalar($N, 2 * $c1), $V);
return new Raytracer_Ray($P, $R1);
}
