feat (wip): real-time gui with rendering in opengl

src/gui/MainWindow.cpp

@@ -0,0 +1,125 @@
+#include "MainWindow.h"
+
+#include <iostream>
+#include <memory>
+
+Window::Window(unsigned int w, unsigned int h) {
+  Window::w = w;
+  Window::h = h;
+}
+
+void framebuffer_size_callback(GLFWwindow* window, int w, int h) {
+  // This function is called by glfw when the window is reized.
+  glViewport(0 , 0, w, h);
+  Window* newWin = reinterpret_cast<Window*>(glfwGetWindowUserPointer(window));
+  newWin->resize(w, h);
+
+}
+
+int Window::init() {
+  // init glfw
+  glfwInit();
+  // requesting context version 1.0 makes glfw try to provide the latest version if possible
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 1);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+
+  this->window = glfwCreateWindow(this->w, this->h, "CUDA ray tracing", NULL, NULL);
+
+  //hide cursor
+  glfwSetInputMode(this->window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
+  glfwSetWindowUserPointer(this->window, reinterpret_cast<void*>(this));
+
+  if (this->window == NULL) {
+    std::cout << "Failed to create window\n";
+    glfwTerminate();
+    return -1;
+  }
+
+	glfwMakeContextCurrent(this->window);
+
+
+  // init glad(opengl)
+  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
+    std::cout << "Failed to initialize GLAD\n";
+    return -1;
+  }
+
+
+  // init framebuffer
+  glViewport(0, 0, this->w, this->h);
+  if (glfwSetFramebufferSizeCallback(this->window, framebuffer_size_callback) != 0) return -1;
+
+
+  if (init_quad()) return -1;
+	this->last_frame = std::chrono::steady_clock::now();
+
+  while (!glfwWindowShouldClose(window)) {
+    Window::tick();
+  }
+
+  Window::free();
+  return 0;
+}
+
+
+int Window::init_quad() {
+  this->current_quad = std::make_unique<Quad>(this->w, this->h);
+  this->current_quad->cuda_init();
+
+  // TODO: default shaders
+  return 0;
+}
+
+
+void Window::free() {
+  // To preserve the proper destruction order we forcefully set the quads to null (calling their destructor in the process)
+  // Not strictly necessary, but i saw some weird errors on exit without this so best to keep it in.
+  this->current_quad = nullptr;
+
+  glfwDestroyWindow(window);
+  glfwTerminate();
+}
+
+
+void Window::tick() {
+  // manually track time diff
+	std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now();
+  float diff = (float) std::chrono::duration_cast<std::chrono::milliseconds>(now - this->last_frame).count();
+  this->last_frame = now;
+
+  // TODO: remove debug line at some point
+  std::cout << 1000.0/diff << " fps\n";
+
+  // TODO: code input logic and class/struct and stuff
+  // ticking input probably involves 4? steps:
+  // * check if window needs to be closed (escape/q pressed)
+  // * check if camera moved (wasd/hjkl pressed)
+  // (phase 3/do later): check if we switched from realtime tracing to that other option - maybe a pause function? (p pressed?)
+  // * if moved -> update camera (raytracing will involve some logic here too? see when i get there)
+  
+  // tick render
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	glDisable(GL_DEPTH_TEST);
+
+	glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+  // render frame
+	glBindFramebuffer(GL_FRAMEBUFFER, this->current_quad->fb);
+	this->current_quad->render();
+	glBindVertexArray(this->current_quad->VAO);
+	glBindTexture(GL_TEXTURE_2D, this->current_quad->tex);
+	glDrawArrays(GL_TRIANGLES, 0, 6); // draw current frame to texture
+  
+  // check for events
+  // + swap buffers; TODO: check if necessary?
+	glfwSwapBuffers(this->window);
+	glfwPollEvents();
+  
+}
+
+void Window::resize(unsigned int w, unsigned int h) {
+  this->w = w;
+  this->h = h;
+  this->current_quad->resize(w, h);
+}

src/gui/MainWindow.h

@@ -0,0 +1,32 @@
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include "Quad.h"
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <chrono>
+
+
+class Window {
+public:
+  unsigned int w;
+  unsigned int h;
+
+  Window(unsigned int w, unsigned int h);
+
+  int init();
+  void free();
+  void resize(unsigned int w, unsigned int h);
+
+private:
+  GLFWwindow* window;
+  std::unique_ptr<Quad> current_quad;
+
+	std::chrono::steady_clock::time_point last_frame;
+
+  void tick();
+  int init_quad();
+
+  // std::unique_ptr<Shader> shader;
+};
+#endif // MAINWINDOW_H

src/gui/Quad.cpp

@@ -0,0 +1,136 @@
+#include "Quad.h"
+
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include "cuda_runtime.h"
+#include "device_launch_parameters.h"
+#include <cuda_gl_interop.h>
+#include <iostream>
+
+Quad::Quad(unsigned int w, unsigned int h) {
+  this->w = w;
+  this->h = h;
+
+  std::vector<float> vertices = {
+    -1.0f,  1.0f,  0.0f, 1.0f,
+    -1.0f, -1.0f,  0.0f, 0.0f,
+     1.0f, -1.0f,  1.0f, 0.0f,
+
+    -1.0f,  1.0f,  0.0f, 1.0f,
+     1.0f, -1.0f,  1.0f, 0.0f,
+     1.0f,  1.0f,  1.0f, 1.0f
+  };
+
+  glGenBuffers(1, &VBO);
+  glGenVertexArrays(1, &VAO);
+
+  glBindVertexArray(VAO);
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+  
+  // copy vertex data to buffer on gpu
+  glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(float), vertices.data(), GL_STATIC_DRAW);
+
+  // set our vertex attributes pointers
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
+
+  glEnableVertexAttribArray(1);
+  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
+
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindVertexArray(0);
+
+  // texture stuff
+  glGenBuffers(1, &PBO);
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, PBO);
+  glBufferData(GL_PIXEL_UNPACK_BUFFER, w * h * 4, NULL, GL_DYNAMIC_COPY);
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
+
+  glEnable(GL_TEXTURE_2D);
+
+  glGenTextures(1, &tex);
+
+  glBindTexture(GL_TEXTURE_2D, tex);
+
+  // parameters for texture
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
+  glBindTexture(GL_TEXTURE_2D, 0);
+
+  // register the FBO
+  glGenFramebuffers(1, &fb);
+  glBindFramebuffer(GL_FRAMEBUFFER, fb);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, this->tex, 0);
+  glBindFramebuffer(GL_FRAMEBUFFER, 0);
+};
+
+
+Quad::~Quad() {
+  int res = cudaGraphicsUnregisterResource(CGR);
+  if (res) {
+    std::cout << "CUDA error while deregistering the graphics resource: " << res;
+    cudaDeviceReset();
+    exit(1);
+  }
+};
+
+
+void Quad::cuda_init() {
+  int res = cudaGraphicsGLRegisterBuffer(&this->CGR, this->PBO, cudaGraphicsRegisterFlagsNone); 
+  if (res) {
+    std::cout << "CUDA error while registering the graphics resource: " << res;
+    cudaDeviceReset();
+    exit(1);
+  }
+  this->renderer = std::make_unique<Raycaster>(this->CGR, this->w, this->h);
+};
+
+
+void Quad::render() {
+  glBindTexture(GL_TEXTURE_2D, 0);
+  this->renderer->render(); 
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, this->PBO);
+  glBindTexture(GL_TEXTURE_2D, this->tex);
+  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, this->w, this->h, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
+};
+
+
+void Quad::resize(unsigned int w, unsigned int h) {
+  this->w = w;
+  this->h = h;
+
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, this->PBO);
+  glBufferData(GL_PIXEL_UNPACK_BUFFER, w * h * 4, NULL, GL_DYNAMIC_COPY);
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
+
+  glBindTexture(GL_TEXTURE_2D, this->tex);
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
+  glBindTexture(GL_TEXTURE_2D, 0);
+
+  glBindFramebuffer(GL_FRAMEBUFFER, this->fb);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, this->tex, 0);
+  glBindFramebuffer(GL_FRAMEBUFFER, 0);    
+
+  if (this->renderer != nullptr) {
+    // TODO: probably make a function for the cuda error checking
+    int res = cudaGraphicsUnregisterResource(CGR);
+    if (res) {
+      std::cout << "CUDA error while deregistering the graphics resource: " << res;
+      cudaDeviceReset();
+      exit(1);
+    }
+
+    res = cudaGraphicsGLRegisterBuffer(&this->CGR, this->PBO, cudaGraphicsRegisterFlagsNone); 
+    if (res) {
+      std::cout << "CUDA error while registering the graphics resource: " << res;
+      cudaDeviceReset();
+      exit(1);
+    }
+      this->renderer->resources = this->CGR;
+      this->renderer->resize(w, h);
+  }
+};

src/gui/Quad.h

@@ -0,0 +1,36 @@
+#ifndef QUAD_H
+#define QUAD_H
+
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <cuda_runtime.h>
+
+#include "illumination/Raycaster.h"
+
+#include <vector>
+#include <memory>
+
+class Quad {
+public:
+  unsigned int VAO;
+  unsigned int VBO;
+  unsigned int PBO;
+  cudaGraphicsResource_t CGR;
+
+  unsigned int tex;
+  unsigned int fb;
+
+  unsigned int w;
+  unsigned int h;
+
+  std::unique_ptr<Raycaster> renderer; 
+
+  Quad(unsigned int w, unsigned int h);
+  ~Quad(); 
+
+  void render();
+  void resize(unsigned int w, unsigned int h);
+  void cuda_init();
+
+};
+#endif // QUAD_H

src/gui/shaders/rendertype_accumulate.frag

@@ -0,0 +1,19 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec2 TexCoords;
+
+uniform sampler2D currentFrameTex;
+uniform sampler2D lastFrameTex;
+uniform int frameCount;
+
+#define MAX_FRAMES 500.0f
+
+void main()
+{
+    vec3 col = texture(currentFrameTex, TexCoords).rgb;
+    vec3 col2 = texture(lastFrameTex, TexCoords).rgb;
+
+    col = mix(col, col2, min(frameCount/MAX_FRAMES,1.0f));
+    FragColor = vec4(col, 1.0);
+}

src/gui/shaders/rendertype_accumulate.vert

@@ -0,0 +1,11 @@
+#version 330 core
+layout(location = 0) in vec2 aPos;
+layout(location = 1) in vec2 aTexCoords;
+
+out vec2 TexCoords;
+
+void main()
+{
+    TexCoords = aTexCoords;
+    gl_Position = vec4(aPos.x, aPos.y, 0.0, 1.0);
+}

src/gui/shaders/rendertype_screen.frag

@@ -0,0 +1,12 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec2 TexCoords;
+
+uniform sampler2D screenTexture;
+
+void main()
+{
+    vec3 col = texture(screenTexture, TexCoords).rgb;
+    FragColor = vec4(col, 1.0);
+}

src/gui/shaders/rendertype_screen.vert

@@ -0,0 +1,11 @@
+#version 330 core
+layout(location = 0) in vec2 aPos;
+layout(location = 1) in vec2 aTexCoords;
+
+out vec2 TexCoords;
+
+void main()
+{
+    TexCoords = aTexCoords;
+    gl_Position = vec4(aPos.x, aPos.y, 0.0, 1.0);
+}