/**
* The fresnel rayTrace function creates a fresnel effect for the objects it affects.
*/
glm::vec3 rayTrace(Ray &ray, const float& t, const glm::vec3& normal, RayTracerState& state) {
glm::vec3 n = glm::normalize(normal);
glm::vec3 v = glm::normalize(ray.getDirection());
if(glm::dot(n, v) < 0.0f){
glm::vec3 refl_dir = reflect(n, v);
glm::vec3 refract_dir = refract(n, v, eta_in);
float fresnel = RF0_in + (1.0f-RF0_in)*glm::pow((1.0f-glm::dot(-v, n)), 5.0f);
float reflect_contribution = ray.getColorContribution()*fresnel;
float refract_contribution = ray.getColorContribution()*(1.0f-fresnel);
glm::vec3 reflect = state.rayTrace(ray.spawn(t, refl_dir, reflect_contribution));
glm::vec3 refract = state.rayTrace(ray.spawn(t, refract_dir, refract_contribution));
return glm::mix(refract, reflect, fresnel);
}
else {
glm::vec3 refl_dir(glm::reflect(v, n));
glm::vec3 refract_dir = refract(-n, v, eta_out);
float fresnel = RF0_out + (1.0f-RF0_out)*glm::pow((1.0f-glm::dot(refract_dir, n)), 5.0f);
float reflect_contribution = ray.getColorContribution()*fresnel;
float refract_contribution = ray.getColorContribution()*(1.0f-fresnel);
glm::vec3 reflect = state.rayTrace(ray.spawn(t, refl_dir, reflect_contribution));
glm::vec3 refract = state.rayTrace(ray.spawn(t, refract_dir, refract_contribution));
return glm::mix(refract, reflect, fresnel);
}
}
glm::vec3 rayTrace(Ray &ray, const float& t, const glm::vec3& normal, RayTracerState& state) {
glm::vec3 p = ray.getOrigin() + (t*ray.getDirection());
Ray reflected_ray(p, glm::reflect(ray.getDirection(), normal));
float dotval = glm::dot(normal, -ray.getDirection());
float s = 0.7f;
dotval = s*1.0f + (1.0f-s) * dotval;
return state.rayTrace(reflected_ray) * dotval;
}
glm::vec3 rayTrace(Ray &ray, const float& t, const glm::vec3& normal, RayTracerState& state) {
glm::vec3 n = glm::normalize(normal);
glm::vec3 v = glm::normalize(ray.getDirection());
glm::vec3 reflect = glm::reflect(v, n);
Ray reflect_ray = ray.spawn(t, reflect, 10);
glm::vec3 reflect1 = state.rayTrace(reflect_ray);
return glm::vec3(reflect1);
}
glm::vec3 rayTrace(Ray &ray, const float& t, const glm::vec3& normal, RayTracerState& state) {
const float eta_air = 1.000293f;
const float eta_carbondioxide = 1.00045f;
const float eta_water = 1.3330f;
const float eta_ethanol = 1.361f;
const float eta_pyrex = 1.470f;
const float eta_diamond = 2.419f;
const float eta0 = eta_air;
const float eta1 = eta_water;
float eta = eta0/eta1;
float R0 = pow((eta0-eta1)/(eta0+eta1), 2.0f);
glm::vec3 n = normal;
glm::vec3 v = ray.getDirection();
float fresnel;
glm::vec3 reflect;
glm::vec3 refract;
/*
if(glm::dot(v, n) <= 0) {
// enter
R0 = pow((eta0-eta1)/(eta0+eta1), 2.0f);
eta = eta0/eta1;
newRefractDir = glm::refract(v, n, eta);
newReflectDir = glm::reflect(v, n);
fresnel = R0 + (1.0f-R0)*glm::pow((1.0f-glm::dot(-v, n)), 5.0f);
} else {
// exit
R0 = pow((eta1-eta0)/(eta0+eta1), 2.0f);
eta = eta1/eta0;
newRefractDir = glm::refract(v, -n, eta);
newReflectDir = glm::reflect(v, -n);
fresnel = R0 + (1.0f-R0)*glm::pow((1.0f-glm::dot(newRefractDir, n)), 5.0f);
}
if(glm::dot(v, n) <= 0) { // enter
R0 = pow((eta0-eta1)/(eta0+eta1), 2.0f);
eta = eta0/eta1;
refract = glm::refract(v, n, eta);
reflect = glm::reflect(v, n);
fresnel = R0 + (1.0f-R0)*glm::pow((1.0f-glm::dot(-v, n)), 5.0f);
} else { //exit
R0 = pow((eta1-eta0)/(eta0+eta1), 2.0f);
eta = eta1/eta0;
//reflect = glm::reflect(v, n);
//refract = glm::refract(v, n, eta);
refract = glm::refract(v, -n, eta);
reflect = glm::reflect(v, -n);
fresnel = R0 + (1.0f-R0)*glm::pow((1.0f-glm::dot(refract, n)), 5.0f);
} */
if(glm::dot(v, n) >= 0) { // exiting
R0 = pow((eta1-eta0)/(eta0+eta1), 2.0f);
eta = eta1/eta0;
//fresnel = R0 + (1.0f-R0)*pow((1.0f-glm::dot(v, n)), 5.0f);
//reflect = glm::reflect(v, n);
//refract = glm::refract(v, n, eta);
refract = glm::refract(v, -n, eta);
reflect = glm::reflect(v, -n);
fresnel = R0 + (1.0f-R0)*glm::pow((1.0f-glm::dot(refract, n)), 5.0f);
} else { //entering
R0 = pow((eta0-eta1)/(eta0+eta1), 2.0f);
eta = eta0/eta1;
refract = glm::refract(-v, n, eta);
reflect = glm::reflect(-v, n);
fresnel = R0 + (1.0f-R0)*glm::pow((1.0f-glm::dot(-v, n)), 5.0f);
}
Ray reflect_ray = ray.spawn(t, reflect, 10);
Ray refract_ray = ray.spawn(t, refract, 10);
glm::vec3 reflect1 = state.rayTrace(reflect_ray);
glm::vec3 refract1 = state.rayTrace(refract_ray);
refract1 *= glm::vec3(eta, 1.0f, eta);
//return normal;
return glm::mix(refract1, reflect1, fresnel);
//return refract1;
}
glm::vec3 rayTrace(Ray &ray, const float& t, const glm::vec3& normal, RayTracerState& state) {
return state.rayTrace(ray.spawn(t, glm::reflect(ray.getDirection(), normal), ray.getColorContribution() - absorb_amount));
}