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