COSC-3P93-Project/Step 3/include/engine/raytracing.h

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/*
* Created by Brett Terpstra 6920201 on 16/10/22.
* Copyright (c) 2022 Brett Terpstra. All Rights Reserved.
*
* The general class for all things raytracing!
*/
#ifndef STEP_2_RAYTRACING_H
#define STEP_2_RAYTRACING_H
#include "engine/math/vectors.h"
#include "engine/image/image.h"
#include "engine/util/parser.h"
#include "world.h"
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#include <utility>
#include <mutex>
#include <thread>
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#include <queue>
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namespace Raytracing {
class Camera {
private:
/* Image details */
const Image image;
const PRECISION_TYPE aspectRatio;
/* Camera details */
PRECISION_TYPE viewportHeight;
PRECISION_TYPE viewportWidth;
PRECISION_TYPE focalLength = 1.0;
const PRECISION_TYPE NEAR_PLANE = 0.1;
const PRECISION_TYPE FAR_PLANE = 500;
PRECISION_TYPE tanFovHalf;
PRECISION_TYPE frustumLength;
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Vec4 position{0, 0, 0};
Vec4 horizontalAxis;
Vec4 verticalAxis;
Vec4 imageOrigin;
Vec4 up {0, 1, 0};
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public:
Camera(PRECISION_TYPE fov, const Image& image): image(image),
aspectRatio(double(image.getWidth()) / double(image.getHeight())) {
// scale the viewport height based on the camera's FOV
tanFovHalf = tan(degreeeToRadian(fov) / 2);
viewportHeight = (2.0 * tanFovHalf);
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// with must respect the aspect ratio of the image, otherwise we'd get funky results
viewportWidth = (aspectRatio * viewportHeight);
frustumLength = FAR_PLANE - NEAR_PLANE;
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// horizontal direction from the camera. used to translate the camera
horizontalAxis = (Vec4{viewportWidth, 0, 0, 0});
// virtual direction, also used to translate the camera
verticalAxis = (Vec4{0, viewportHeight, 0, 0});
// lower left of the camera's view port. used to project our vectors from image space to world space
imageOrigin = (position - horizontalAxis / 2 - verticalAxis / 2 - Vec4(0, 0, focalLength, 0));
tlog << viewportHeight << "\n";
tlog << viewportWidth << "\n";
tlog << "\n";
tlog << horizontalAxis << "\n";
tlog << verticalAxis << "\n";
tlog << imageOrigin << "\n";
}
Ray projectRay(PRECISION_TYPE x, PRECISION_TYPE y);
void setPosition(const Vec4& pos) { this->position = pos; }
void setRotation(PRECISION_TYPE yaw, PRECISION_TYPE pitch);
// the follow utility functions are actually taking forever to get right
// I can't tell if my projection calculation is off or the view calc?
// got to install GLM to test which function works and which does. Maybe they are both bad. or Maybe it's my matrix impl
// or maybe the whole rendering stack sucks
[[nodiscard]] Mat4x4 project() const {
Mat4x4 project {emptyMatrix};
// this should be all it takes to create a mostly correct projection matrix
project.m00(float(1.0 / (aspectRatio * tanFovHalf)));
project.m11(float(1.0 / tanFovHalf));
project.m22(float(-((FAR_PLANE + NEAR_PLANE) / frustumLength)));
// this has been transposed
project.m32(-1);
project.m23(float(-((2 * NEAR_PLANE * FAR_PLANE) / frustumLength)));
//project.m33(0);
return project;
// use GLM to debug issues with ^
//glm::mat4 projectG = glm::perspective(glm::radians(90.0f), (float)aspectRatio, 0.1f, (float)1000);
//return Mat4x4{projectG};
}
[[nodiscard]] Mat4x4 view(const Vec4& lookAtPos) const {
Mat4x4 view;
auto w = (position - lookAtPos).normalize(); // forward
auto u = (Vec4::cross(up, w)).normalize(); // right
auto v = Vec4::cross(w, u); // up
view.m00(float(w.x()));
view.m01(float(w.y()));
view.m02(float(w.z()));
view.m03(float(w.w()));
view.m10(float(u.x()));
view.m11(float(u.y()));
view.m12(float(u.z()));
view.m13(float(u.w()));
view.m20(float(v.x()));
view.m21(float(v.y()));
view.m22(float(v.z()));
view.m23(float(v.w()));
// view matrix are inverted, dot product to simulate translate matrix multiplication
view.m30(-float(Vec4::dot(u, position)));
view.m31(-float(Vec4::dot(v, position)));
view.m32(-float(Vec4::dot(w, position)));
view.m33(1);
return view;
}
Mat4x4 view(PRECISION_TYPE yaw, PRECISION_TYPE pitch);
[[nodiscard]] inline Vec4 getPosition() const {return position;};
// the camera's position must be set with setPosition(Vec4);
// uses an internal up vector, assumed to be {0, 1, 0}
// will make the camera look at provided position with respects to the current camera position.
void lookAt(const Vec4& lookAtPos);
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};
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static Random rnd{-1.0, 1.0};
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struct RaycasterImageBounds {
int width,height, x,y;
};
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class Raycaster {
private:
int maxBounceDepth = 50;
int raysPerPixel = 50;
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Camera& camera;
Image& image;
World& world;
std::vector<std::unique_ptr<std::thread>> executors {};
// is the raytracer still running?
bool stillRunning = true;
unsigned int finishedThreads = 0;
unsigned int system_threads = std::thread::hardware_concurrency();
// yes this is actually the only sync we need between the threads
// and compared to the actual runtime of the raytracing it's very small!
std::mutex queueSync;
std::queue<RaycasterImageBounds>* unprocessedQuads = nullptr;
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Vec4 raycasti(const Ray& ray, int depth);
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Vec4 raycast(const Ray& ray);
void runRaycastingAlgorithm(RaycasterImageBounds imageBounds, int loopX, int loopY);
void runSTDThread(int threads);
void runOpenMP(int threads);
void runMPI(int threads);
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public:
inline void updateRayInfo(int maxBounce, int perPixel){
raysPerPixel = perPixel;
maxBounceDepth = maxBounce;
}
inline void resetRayInfo(){
raysPerPixel = 50;
maxBounceDepth = 50;
}
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inline static Vec4 randomUnitVector() {
// there are two methods to generating a random unit sphere
// one which is fast and approximate:
auto v = Vec4(rnd.getDouble(), rnd.getDouble(), rnd.getDouble());
return v.normalize();
// and the one which generates an actual unit vector
/*while (true) {
auto v = Vec4(rnd.getDouble(), rnd.getDouble(), rnd.getDouble());
if (v.lengthSquared() >= 1)
continue;
return v;
}*/
// the second creates better results but is 18% slower (better defined shadows)
// likely due to not over generating unit vectors biased towards the corners
}
Raycaster(Camera& c, Image& i, World& world, const Parser& p): camera(c), image(i), world(world) {
world.generateBVH();
}
void run(bool multithreaded, int threads = 0);
[[nodiscard]] inline bool areThreadsStillRunning() const {return finishedThreads == executors.size();}
inline void join(){
for (auto& p : executors)
p->join();
}
void deleteThreads(){
for (auto& p : executors){
// wait for all threads to exit before trying to delete them.
try {
if (p->joinable())
p->join();
} catch (std::exception& e){}
}
// since executors contains the only reference to the unique_ptr it will be deleted automatically
executors.clear();
}
~Raycaster() {
deleteThreads();
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delete(unprocessedQuads);
}
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};
}
#endif //STEP_2_RAYTRACING_H