Commit of work up to day 11 of learnopengl.com.

03-textures/src/dbc.cpp

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+#include "dbc.hpp"
+#include <iostream>
+
+void dbc::log(const string &message, const std::source_location location) {
+  std::cout << '[' << location.file_name() << ':'
+     << location.line() << "|"
+     << location.function_name() << "] "
+     << message << std::endl;
+}
+
+void dbc::sentinel(const string &message, const std::source_location location) {
+  string err = $F("[SENTINEL!] {}", message);
+  dbc::log(err, location);
+  throw dbc::SentinelError(err);
+}
+
+void dbc::pre(const string &message, bool test, const std::source_location location) {
+  if(!test) {
+    string err = $F("[PRE!] {}", message);
+    dbc::log(err, location);
+    throw dbc::PreCondError(err);
+  }
+}
+
+void dbc::pre(const string &message, std::function<bool()> tester, const std::source_location location) {
+  dbc::pre(message, tester(), location);
+}
+
+void dbc::post(const string &message, bool test, const std::source_location location) {
+  if(!test) {
+    string err = $F("[POST!] {}", message);
+    dbc::log(err, location);
+    throw dbc::PostCondError(err);
+  }
+}
+
+void dbc::post(const string &message, std::function<bool()> tester, const std::source_location location) {
+  dbc::post(message, tester(), location);
+}
+
+void dbc::check(bool test, const string &message, const std::source_location location) {
+  if(!test) {
+    string err = $F("[CHECK!] {}\n", message);
+    dbc::log(err, location);
+    throw dbc::CheckError(err);
+  }
+}

03-textures/src/dbc.hpp

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+#pragma once
+
+#include <string>
+#include <fmt/core.h>
+#include <functional>
+#include <source_location>
+
+// AKA the Fuckit macro
+#define $F(FMT, ...) fmt::format(FMT, ##__VA_ARGS__)
+
+namespace dbc {
+  using std::string;
+
+  using CheckError = std::runtime_error;
+  using SentinelError = std::runtime_error;
+  using PreCondError = std::runtime_error;
+  using PostCondError = std::runtime_error;
+
+  void log(const string &message,
+      const std::source_location location =
+      std::source_location::current());
+
+  [[noreturn]] void sentinel(const string &message,
+      const std::source_location location =
+      std::source_location::current());
+
+  void pre(const string &message, bool test,
+      const std::source_location location =
+      std::source_location::current());
+
+  void pre(const string &message, std::function<bool()> tester,
+      const std::source_location location =
+      std::source_location::current());
+
+  void post(const string &message, bool test,
+      const std::source_location location =
+      std::source_location::current());
+
+  void post(const string &message, std::function<bool()> tester,
+      const std::source_location location =
+      std::source_location::current());
+
+  void check(bool test, const string &message,
+      const std::source_location location =
+      std::source_location::current());
+}

03-textures/src/main.cpp

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+#define _USE_MATH_DEFINES
+#include <math.h>
+#include "dbc.hpp"
+#include <print>
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <vector>
+#include <functional>
+#include "shader.hpp"
+#include <stb_image.h>
+
+void framebuffer_size_callback(GLFWwindow *window, int width, int height);
+void processInput(GLFWwindow *window);
+
+const unsigned int SCR_WIDTH = 800;
+const unsigned int SCR_HEIGHT = 600;
+
+struct Config {
+  Shader shader;
+  unsigned int VAO = 0;
+  unsigned int VBO = 0;
+  unsigned int EBO = 0;
+  unsigned int texture1 = 0;
+  unsigned int texture2 = 0;
+};
+
+void init_glfw() {
+  glfwInit();
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+}
+
+void framebuffer_size_callback(GLFWwindow *, int width, int height) {
+  glViewport(0, 0, width, height);
+}
+
+GLFWwindow* create_window() {
+  GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
+  dbc::check(window != NULL, "failed to open window");
+
+  glfwMakeContextCurrent(window);
+
+  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+  auto good = gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
+  dbc::check(good, "failed to load GLAD");
+
+  return window;
+}
+
+void processInput(GLFWwindow *window) {
+  if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
+    glfwSetWindowShouldClose(window, true);
+  }
+}
+
+unsigned int load_texture(const std::string& image_file) {
+  unsigned int texture_id;
+  glGenTextures(1, &texture_id);
+  glBindTexture(GL_TEXTURE_2D, texture_id);
+
+  // set the texture wrapping parameters
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+  // set texture filtering parameters
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+  int width = 0;
+  int height = 0;
+  int nrChannels = 0;
+  stbi_set_flip_vertically_on_load(true);
+
+  unsigned char *data = stbi_load(image_file.c_str(), &width, &height, &nrChannels, 0);
+
+  dbc::check(data != nullptr, std::format("Failed to load texture: {}", image_file));
+
+  dbc::check(nrChannels == 3 || nrChannels == 4,
+      std::format("Image {} has invalid channels {} should be 3 or 4.", image_file, nrChannels));
+
+  auto rgb_or_a = nrChannels == 3 ? GL_RGB : GL_RGBA;
+
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, rgb_or_a, GL_UNSIGNED_BYTE, data);
+  glGenerateMipmap(GL_TEXTURE_2D);
+
+  stbi_image_free(data);
+
+  return texture_id;
+}
+
+Config setup() {
+  Config config{{"shaders/4.2.texture.vs", "shaders/4.2.texture.fs"}};
+
+  float vertices[] = {
+      // positions          // colors           // texture coords
+       0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
+       0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
+      -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
+      -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left
+  };
+  unsigned int indices[] = {
+      0, 1, 3, // first triangle
+      1, 2, 3  // second triangle
+  };
+
+  unsigned int VBO = 0;
+  unsigned int VAO = 0;
+  unsigned int EBO = 0;
+
+  glGenVertexArrays(1, &VAO);
+  glGenBuffers(1, &VBO);
+  glGenBuffers(1, &EBO);
+
+  glBindVertexArray(VAO);
+
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
+  glEnableVertexAttribArray(0);
+
+  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
+  glEnableVertexAttribArray(1);
+
+  glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
+  glEnableVertexAttribArray(2);
+
+  config.texture1 = load_texture("resources/textures/container.jpg");
+
+  config.texture2 = load_texture("resources/textures/awesomeface.png");
+
+  config.shader.use();
+
+  glUniform1i(glGetUniformLocation(config.shader.ID, "texture1"), 0);
+
+  config.shader.setInt("texture2", 1);
+
+  config.VAO = VAO;
+  config.VBO = VBO;
+  config.EBO = EBO;
+
+  return config;
+}
+
+void render(GLFWwindow* window, const Config& config) {
+  glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+  glClear(GL_COLOR_BUFFER_BIT);
+
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, config.texture1);
+  glActiveTexture(GL_TEXTURE1);
+  glBindTexture(GL_TEXTURE_2D, config.texture2);
+
+  config.shader.use();
+  glBindVertexArray(config.VAO);
+  glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+
+  glfwSwapBuffers(window);
+  glfwPollEvents();
+}
+
+void cleanup(Config& config) {
+  glDeleteVertexArrays(1, &config.VAO);
+  glDeleteBuffers(1, &config.VAO);
+  glDeleteBuffers(1, &config.VBO);
+  glDeleteBuffers(1, &config.EBO);
+  config.shader.cleanup();
+}
+
+int main() {
+  init_glfw();
+
+  auto window = create_window();
+
+  auto config = setup();
+
+  while(!glfwWindowShouldClose(window)) {
+    processInput(window);
+    render(window, config);
+  }
+
+  cleanup(config);
+
+  glfwTerminate();
+
+  return 0;
+}

03-textures/src/shader.cpp

@@ -0,0 +1,101 @@
+#include "shader.hpp"
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <print>
+#include <filesystem>
+#include "dbc.hpp"
+
+namespace fs = std::filesystem;
+
+inline std::string read_file(const std::string& filename) {
+  // load the file
+  std::ifstream in_file{filename, std::ios::binary};
+
+  // get the size of the file
+  std::stringstream in_str;
+  in_str << in_file.rdbuf();
+  return in_str.str();
+}
+
+void check_error(const std::string& what, unsigned int thing, GLenum check_type) {
+  int success = 0;
+  char infoLog[512] = {0};
+
+  if(check_type == GL_LINK_STATUS) {
+    glGetProgramiv(thing, check_type, &success);
+
+    if(!success) {
+      glGetProgramInfoLog(thing, 512, NULL, infoLog);
+      dbc::sentinel(std::format("ERROR: Program {} compile failed: {}", what, infoLog));
+    }
+  } else {
+    glGetShaderiv(thing, check_type, &success);
+
+    if(!success) {
+      glGetShaderInfoLog(thing, 512, NULL, infoLog);
+      dbc::sentinel(std::format("ERROR: Shader {} compile failed: {}", what, infoLog));
+    }
+  }
+}
+
+unsigned int Shader::load_shader(const std::string& filename, GLenum shader_type) {
+  dbc::check(fs::exists(filename),
+      std::format("shader file {} does not exist", filename));
+
+  // create the shader
+  std::string shader_code = read_file(filename);
+  const char* shader_code_ptr = shader_code.c_str();
+
+  int shader_id = glCreateShader(shader_type);
+  glShaderSource(shader_id, 1, &shader_code_ptr, NULL);
+  glCompileShader(shader_id);
+
+  check_error(filename, shader_id, GL_COMPILE_STATUS);
+
+  // check compile error
+  return shader_id;
+}
+
+Shader::Shader(const char* vertexPath, const char* fragmentPath) {
+  unsigned int vertex = load_shader(vertexPath, GL_VERTEX_SHADER);
+  unsigned int fragment = load_shader(fragmentPath, GL_FRAGMENT_SHADER);
+
+  ID = glCreateProgram();
+  glAttachShader(ID, vertex);
+  glAttachShader(ID, fragment);
+  glLinkProgram(ID);
+
+  check_error("link", ID, GL_LINK_STATUS);
+
+  glDeleteShader(vertex);
+  glDeleteShader(fragment);
+}
+
+void Shader::use() const {
+  glUseProgram(ID);
+}
+
+void Shader::cleanup() {
+  glDeleteProgram(ID);
+}
+
+void Shader::setBool(const std::string &name, bool value) const {
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform1i(uniform, (int)value);
+}
+
+void Shader::setInt(const std::string &name, int value) const {
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform1i(uniform, value);
+}
+
+void Shader::setFloat(const std::string &name, float value) const {
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform1f(uniform, value);
+}
+
+void Shader::setVec4(const std::string &name, float v1, float v2, float v3, float v4) const {
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform4f(uniform, v1, v2, v3, v4);
+}

03-textures/src/shader.hpp

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+#pragma once
+
+#include <glad/glad.h>
+#include <string>
+#include <climits>
+
+class Shader
+{
+public:
+  unsigned int ID = UINT_MAX;
+
+  Shader(const char* vertexPath, const char* fragmentPath);
+  unsigned int load_shader(const std::string& filename, GLenum shader_type);
+  void use() const;
+  void setBool(const std::string &name, bool value) const;
+  void setInt(const std::string &name, int value) const;
+  void setFloat(const std::string &name, float value) const;
+  void setVec4(const std::string &name, float v1, float v2, float v3, float v4) const;
+  void cleanup();
+};

03-textures/src/stb_image.cpp

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+#define STB_IMAGE_IMPLEMENTATION
+#include <stb_image.h>