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 rayTrace(RayTracer_IntersectionInfo $info, RayTracer_Ray $ray, RayTracer_Scene $scene, $depth)
{
// Calc ambient
$color = RayTracer_Color::multiplyScalar($info->color, $scene->background->ambience);
$shininess = pow(10, $info->shape->material->gloss + 1);
foreach ($scene->lights as $light) {
// Calc diffuse lighting
$v = RayTracer_Vector::subtract($light->position, $info->position)->normalize();
if ($this->options['renderDiffuse']) {
$L = $v->dot($info->normal);
if ($L > 0.0) {
$color = RayTracer_Color::add($color, RayTracer_Color::multiply($info->color, RayTracer_Color::multiplyScalar($light->color, $L)));
}
}
// The greater the depth the more accurate the colours, but
// this is exponentially (!) expensive
if ($depth <= $this->options['rayDepth']) {
// calculate reflection ray
if ($this->options['renderReflections'] && $info->shape->material->reflection > 0) {
$reflectionRay = $this->getReflectionRay($info->position, $info->normal, $ray->direction);
$refl = $this->testIntersection($reflectionRay, $scene, $info->shape);
if ($refl->isHit && $refl->distance > 0) {
$refl->color = $this->rayTrace($refl, $reflectionRay, $scene, $depth + 1);
} else {
$refl->color = $scene->background->color;
}
$color = RayTracer_Color::blend($color, $refl->color, $info->shape->material->reflection);
}
// Refraction
/* TODO */
}
/* Render shadows and highlights */
$shadowInfo = new RayTracer_IntersectionInfo();
if ($this->options['renderShadows']) {
$shadowRay = new RayTracer_Ray($info->position, $v);
$shadowInfo = $this->testIntersection($shadowRay, $scene, $info->shape);
if ($shadowInfo->isHit && $shadowInfo->shape != $info->shape) {
$vA = RayTracer_Color::multiplyScalar($color, 0.5);
$dB = 0.5 * pow($shadowInfo->shape->material->transparency, 0.5);
$color = RayTracer_Color::addScalar($vA, $dB);
}
}
// Phong specular highlights
if ($this->options['renderHighlights'] && !$shadowInfo->isHit && $info->shape->material->gloss > 0) {
$Lv = RayTracer_Vector::subtract($info->shape->position, $light->position)->normalize();
$E = RayTracer_Vector::subtract($scene->camera->position, $info->shape->position)->normalize();
$H = RayTracer_Vector::subtract($E, $Lv)->normalize();
$glossWeight = pow(max($info->normal->dot($H), 0), $shininess);
$color = RayTracer_Color::add(RayTracer_Color::multiplyScalar($light->color, $glossWeight), $color);
}
}
$color->limit();
return $color;
}
