Color traceRay(Ray* ray, Scene* scene, int objectCount, int lightCount, int maxBounces, double ambientLighting) {
Color shaderResult (0,0,0);
Ray* shadowRay = new Ray();
Ray* reflectionRay = new Ray();
RayIntersection primaryObjectHit = testRayIntersection(ray, scene, objectCount, 0, MINIMAL_DISTANCE);
if(primaryObjectHit.objectId >= 0) {
Object* sceneObject = scene->getObjectList().at(primaryObjectHit.objectId);
// calulate brightness and specularity
Color specular (0,0,0);
Color diffuse (0,0,0);
Color reflection (0,0,0);
Vect intersectionPoint = primaryObjectHit.location;
Color ambient = sceneObject->getColorAt(intersectionPoint).scale(ambientLighting);
shadowRay->setOrigin(intersectionPoint);
Vect normalAtIntersection = sceneObject->getNormalAt(intersectionPoint);
Vect reflectionDirection = ray->getReflectingDirection(normalAtIntersection);
double lightImportance = 1;
if(lightCount > 1) {
lightImportance = 1.0 / lightCount;
}
for(int lightIndex = 0; lightIndex < lightCount; lightIndex++) {
Light *lightSource = scene->getLightList().at(lightIndex);
Vect pointToLightVect = lightSource->getPosition().subtract(intersectionPoint);
Vect lightDirection = pointToLightVect.normalize();
// Test if light is visible or hidden to render shadows
double diffuseFactor = normalAtIntersection.dot(lightDirection);
double specularFactor = reflectionDirection.dot(lightDirection);
bool shadowed = false;
if(diffuseFactor > 0) // object is facing the light source - add diffuse
{
// check if it is shadowed;
shadowRay->setDirection(lightDirection);
double lightDistance = pointToLightVect.magnitude();
shadowed = (testRayIntersection(shadowRay, scene, objectCount, lightDistance, MINIMAL_DISTANCE).objectId > -1);
}
if(!shadowed && diffuseFactor > 0) {
diffuse = diffuse.add(sceneObject->getColorAt(intersectionPoint).scale(diffuseFactor));
}
if(!shadowed && specularFactor > 0 && sceneObject->getMaterial().getRoughness() > 0) {
specular = specular.add(lightSource->getColor().scale(pow(specularFactor, 10) * sceneObject->getMaterial().getRoughness()));
}
}
if(maxBounces > 0 && sceneObject->getMaterial().getReflectivity() > 0) {
reflectionRay->setOrigin(intersectionPoint);
reflectionRay->setDirection(reflectionDirection);
reflection = traceRay(reflectionRay, scene, objectCount, lightCount, --maxBounces, ambientLighting).scale(sceneObject->getMaterial().getReflectivity() * 0.25);
}
shaderResult = ambient.add(diffuse).add(specular).add(reflection).normalize();
} else {
shaderResult = scene->getBackgroundColor();
}
delete shadowRay;
delete reflectionRay;
return shaderResult;
}
