/* * Created by Brett Terpstra 6920201 on 16/10/22. * Copyright (c) 2022 Brett Terpstra. All Rights Reserved. */ #include #include namespace Raytracing { World::~World() { for (auto* p: objects) delete (p); for (const auto& p: materials) delete (p.second); } HitData SphereObject::checkIfHit(const Ray& ray, PRECISION_TYPE min, PRECISION_TYPE max) const { PRECISION_TYPE radiusSquared = radius * radius; // move the ray to be with respects to the sphere vec4 RayWRTSphere = ray.getStartingPoint() - position; // now determine the discriminant for the quadratic formula for the function of line sphere intercept PRECISION_TYPE a = ray.getDirection().lengthSquared(); PRECISION_TYPE b = Raytracing::vec4::dot(RayWRTSphere, ray.getDirection()); PRECISION_TYPE c = RayWRTSphere.lengthSquared() - radiusSquared; // > 0: the hit has two roots, meaning we hit both sides of the sphere // = 0: the ray has one root, we hit the edge of the sphere // < 0: ray isn't inside the sphere. PRECISION_TYPE discriminant = b * b - (a * c); // < 0: ray isn't inside the sphere. Don't need to bother calculating the roots. if (discriminant < 0) return {false, vec4(), vec4(), 0}; // now we have to find the root which exists inside our range [min,max] auto root = (-b - std::sqrt(discriminant)) / a; // if the first root isn't in our range if (root < min || root > max) { // check the second root root = (-b + std::sqrt(discriminant)) / a; if (root < min || root > max) { // if the second isn't in the range then we also must return false. return {false, vec4(), vec4(), 0}; } } // the hit point is where the ray is when extended to the root auto RayAtRoot = ray.along(root); // The normal of a sphere is just the point of the hit minus the center position auto normal = (RayAtRoot - position).normalize(); /*if (Raytracing::vec4::dot(ray.getDirection(), normal) > 0.0) { tlog << "ray inside sphere\n"; } else tlog << "ray outside sphere\n"; */ return {true, RayAtRoot, normal, root}; } std::pair World::checkIfHit(const Ray& ray, PRECISION_TYPE min, PRECISION_TYPE max) const { auto hResult = HitData{false, vec4(), vec4(), max}; Object* objPtr = nullptr; for (auto* obj: objects) { // check up to the point of the last closest hit, // will give the closest object's hit result auto cResult = obj->checkIfHit(ray, min, hResult.length); if (cResult.hit) { hResult = cResult; objPtr = obj; } } return {hResult, objPtr}; } ScatterResults DiffuseMaterial::scatter(const Ray& ray, const HitData& hitData) const { vec4 newRay = hitData.normal + Raytracing::Raycaster::randomUnitVector().normalize(); // rays that are close to zero are liable to floating point precision errors if (newRay.x() < EPSILON && newRay.y() < EPSILON && newRay.z() < EPSILON && newRay.w() < EPSILON) newRay = hitData.normal; return {true, Ray{hitData.hitPoint, newRay}, getBaseColor()}; } ScatterResults MetalMaterial::scatter(const Ray& ray, const HitData& hitData) const { // create a ray reflection vec4 newRay = reflect(ray.getDirection().normalize(), hitData.normal); // make sure our reflected ray is outside the sphere and doesn't point inwards bool shouldReflect = vec4::dot(newRay, hitData.normal) > 0; return {shouldReflect, Ray{hitData.hitPoint, newRay}, getBaseColor()}; } ScatterResults BrushedMetalMaterial::scatter(const Ray& ray, const HitData& hitData) const { // create a ray reflection vec4 newRay = reflect(ray.getDirection().normalize(), hitData.normal); // make sure our reflected ray is outside the sphere and doesn't point inwards bool shouldReflect = vec4::dot(newRay, hitData.normal) > 0; return {shouldReflect, Ray{hitData.hitPoint, newRay + Raycaster::randomUnitVector() * fuzzyness}, getBaseColor()}; } static HitData checkIfTriangleGotHit(Triangle theTriangle, vec4 position, const Ray& ray, PRECISION_TYPE min, PRECISION_TYPE max) { // Möller–Trumbore intersection algorithm // https://en.wikipedia.org/wiki/M%C3%B6ller%E2%80%93Trumbore_intersection_algorithm vec4 edge1, edge2, h, s, q; PRECISION_TYPE a, f, u, v; edge1 = (theTriangle.vertex2 + position) - (theTriangle.vertex1 + position); edge2 = (theTriangle.vertex3 + position) - (theTriangle.vertex1 + position); h = vec4::cross(ray.getDirection(), edge2); a = vec4::dot(edge1, h); if (a > -EPSILON && a < EPSILON) return {false, vec4(), vec4(), 0}; //parallel to triangle f = 1.0 / a; s = ray.getStartingPoint() - (theTriangle.vertex1 + position); u = f * vec4::dot(s, h); if (u < 0.0 || u > 1.0) return {false, vec4(), vec4(), 0}; q = vec4::cross(s, edge1); v = f * vec4::dot(ray.getDirection(), q); if (v < 0.0 || u + v > 1.0) return {false, vec4(), vec4(), 0}; // At this stage we can compute t to find out where the intersection point is on the line. PRECISION_TYPE t = f * vec4::dot(edge2, q); if (t > EPSILON) { // ray intersects vec4 rayIntersectionPoint = ray.along(t); vec4 normal; // normal = theTriangle.findClosestNormal(rayIntersectionPoint - position); if (theTriangle.hasNormals) // returning the closest normal is extra computation when n1 would likely be fine. normal = theTriangle.normal1; else { // standard points to normal algorithm but using already computed edges normal = vec4{edge1.y() * edge2.z(), edge1.z() * edge2.x(), edge1.x() * edge2.y()} - vec4{edge1.z() * edge2.y(), edge1.x() * edge2.z(), edge1.y() * edge2.x()}; } return {true, rayIntersectionPoint, normal, t}; } return {false, vec4(), vec4(), 0}; } HitData TriangleObject::checkIfHit(const Ray& ray, PRECISION_TYPE min, PRECISION_TYPE max) const { return checkIfTriangleGotHit(theTriangle, position, ray, min, max); } HitData ModelObject::checkIfHit(const Ray& ray, PRECISION_TYPE min, PRECISION_TYPE max) const { auto hResult = HitData{false, vec4(), vec4(), max}; for (const Triangle& t : triangles) { auto cResult = checkIfTriangleGotHit(t, position, ray, min, hResult.length); if (cResult.hit) hResult = cResult; } return hResult; } }