51 lines
2.1 KiB
C++
51 lines
2.1 KiB
C++
#include "scene/scene.h"
|
|
#include "shader/refractionshader.h"
|
|
|
|
RefractionShader::RefractionShader(float indexInside, float indexOutside) : indexInside(indexInside), indexOutside(indexOutside) {}
|
|
|
|
Color RefractionShader::shade(Scene const &scene, Ray const &ray) const {
|
|
// Circumvent getting environment map color into the mix
|
|
if (ray.getRemainingBounces() > 0) {
|
|
// Get the normal of the primitive which was hit
|
|
Vector3d normalVector = ray.normal;
|
|
|
|
// Calculate the index of refraction
|
|
float refractiveIndex = indexOutside / indexInside;
|
|
// What if we are already inside the object?
|
|
if (dotProduct(normalVector, ray.direction) > 0) {
|
|
normalVector = -normalVector;
|
|
refractiveIndex = indexInside / indexOutside;
|
|
}
|
|
|
|
// Using the notation from the lecture
|
|
float cosineTheta = dotProduct(normalVector, -ray.direction);
|
|
float cosinePhi = std::sqrt(1 + refractiveIndex * refractiveIndex * (cosineTheta * cosineTheta - 1));
|
|
// Calculate t, the new ray direction
|
|
Vector3d t = refractiveIndex * ray.direction + (refractiveIndex * cosineTheta - cosinePhi) * normalVector;
|
|
|
|
// Create the refraction ray
|
|
Ray refractionRay = ray;
|
|
// Reset the ray
|
|
refractionRay.length = INFINITY;
|
|
refractionRay.primitive = nullptr;
|
|
|
|
// Check whether it is a refraction.
|
|
if (dotProduct(t, normalVector) <= 0.0) {
|
|
refractionRay.origin = ray.origin + (ray.length + REFR_EPS) * ray.direction;
|
|
refractionRay.direction = normalized(t);
|
|
} else { // Otherwise, it is a total reflection.
|
|
refractionRay.origin = ray.origin + (ray.length - REFR_EPS) * ray.direction;
|
|
// Next we get the reflection vector
|
|
Vector3d const reflectionVector = ray.direction - 2.0f * dotProduct(normalVector, ray.direction) * normalVector;
|
|
|
|
// Change the ray direction and origin
|
|
refractionRay.direction = normalized(reflectionVector);
|
|
}
|
|
|
|
// Send out a new refracted ray into the scene
|
|
return scene.traceRay(refractionRay);
|
|
}
|
|
return Color(0.0f, 0.0f, 0.0f);
|
|
}
|
|
|
|
bool RefractionShader::isTransparent() const { return true; }
|