bool hitTriang(Photon *photon, Triang *triang, const float distance, const Material *materials)
{
Shader shader = DIFFUSE;
// Better idea?
if (fDot(triang->direct, photon->direct) > -EPSILON)
triang->direct = vNeg(triang->direct);
// Update ray's position to the point where the ray hits the sphere
photon->origin = fFMA(photon->direct, distance - UM(10), photon->origin);
photon->lambda = materials[triang->mID].lambda;
if (shader == CRAZY) {
photon->direct = vNorm(vSub(newVec(0.99, 0, 0), photon->origin));
return REFLECTED;
}
else if (shader == SPECULAR) {
// Angle between new and old vector is twice the angle between old vector and normal
Vec reflect = vDot(photon->direct, triang->direct);
photon->direct = vSub(photon->direct, vMul(triang->direct, vAdd(reflect, reflect)));
return REFLECTED;
}
else if (shader == DIFFUSE) {
photon->direct = randDir();
if (fDot(photon->direct, triang->direct) < EPSILON)
photon->direct = vNeg(photon->direct);
return REFLECTED;
}
else return ABSORBED;
}
void VerletStick::constrainLen() {
for (int i=0; i<constrainLoopCount; i++) {
Vector3df delta = Vector3df(b2->getPos().x-b1->getPos().x,
b2->getPos().y-b1->getPos().y,
b2->getPos().z-b1->getPos().z);
float deltaLength = delta.mag();
float difference = ((deltaLength - len) / deltaLength);
// nudge positiviely
Vector3df vPos(delta.x * (constrainVal.elem0 * tension * difference),
delta.y * (constrainVal.elem0 * tension * difference),
delta.z * (constrainVal.elem0 * tension * difference) );
b1->addPos(vPos);
// nudge negatively
Vector3df vNeg(delta.x * (constrainVal.elem1 * tension * difference),
delta.y * (constrainVal.elem1 * tension * difference),
delta.z * (constrainVal.elem1 * tension * difference) );
b2->subPos(vNeg);
/*std::cout << "b1.getPos() = " << b1.getPos() << std::endl;
std::cout << "vNeg = " << vNeg << std::endl;
std::cout << "deltaLength = " << deltaLength << std::endl;
std::cout << "difference = " << difference << std::endl;*/
}
}
Photon triangEmit(const Triang *triang, const Material *materials)
{
Photon p;
float u = drand48(), v = drand48();
Vec point = vAdd(fMul(triang->vectab, u), fMul(triang->vectac, v));
// If point is outside triangle
if (!triang->rectan && u + v < EPSILONONE)
p.origin = vSub(vAdd(triang->origin, vAdd(triang->vectab, triang->vectac)), point);
else
p.origin = vAdd(triang->origin, point);
p.direct = randDir();
if (fDot(p.direct, triang->direct) > EPSILON)
p.direct = vNeg(p.direct);
p.lambda = materials[triang->mID].lambda;
return p;
}
