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

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);
+  }
+};