function traceRay(&$ray, &$light)
{
$p = $this->intersect($ray, new IntersectionPoint(INFINITY, new Vector(0.0, 0.0, 0.0)));
if (is_infinite($p->distance)) {
return 0.0;
}
$greyscale = -1.0 * $p->normal->dot($light);
if ($greyscale <= 0.0) {
return 0.0;
}
$rayOrigin = $ray->origin;
$scaledDirection = $ray->direction->scaledBy($p->distance);
$scaledNormal = $p->normal->scaledBy(EPSILON);
$o = $rayOrigin->plus($scaledDirection);
$o = $o->plus($scaledNormal);
$v = new Vector(0.0, 0.0, 0.0);
$shadowRay = new Ray($o, $v->minus($light));
$shadowp = $this->intersect($shadowRay, new IntersectionPoint(INFINITY, $p->normal));
if (is_infinite($shadowp->distance)) {
return $greyscale;
} else {
return 0.0;
}
}
public function addLight(Color $col, Light $light, Vector $pos, Scene $scene, Thing $thing, Vector $reflectDir, Vector $norm)
{
$ldis = Vector::minus($light->pos, $pos);
$livec = Vector::norm($ldis);
$neatIsect = $this->testRay(new Ray($pos, $livec), $scene);
$isInShadow = $neatIsect != null && $neatIsect <= Vector::mag($ldis);
if ($isInShadow) {
return $col;
}
$illum = Vector::dot($livec, $norm);
$lcolor = Color::$defaultColor;
if ($illum > 0) {
$lcolor = Color::scale($illum, $light->color);
}
$specular = Vector::dot($livec, Vector::norm($reflectDir));
$scolor = Color::$defaultColor;
$surface = $thing->surface();
if ($specular > 0) {
$scolor = Color::scale(pow($specular, $surface->roughness()), $light->color);
}
return Color::plus($col, Color::plus(Color::times($surface->diffuse($pos), $lcolor), Color::times($surface->specular($pos), $scolor)));
}
