COSC-3P93-Project/Step 2/src/world.cpp

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/*
* Created by Brett Terpstra 6920201 on 16/10/22.
* Copyright (c) 2022 Brett Terpstra. All Rights Reserved.
*/
#include <world.h>
namespace Raytracing {
World::~World() {
for (auto* p : objects)
delete(p);
}
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Object::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};
}
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Object::HitData World::checkIfHit(const Ray& ray, PRECISION_TYPE min, PRECISION_TYPE max) const {
auto hResult = Object::HitData{false, vec4(), vec4(), max};
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;
}
return hResult;
}
}