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

09-basic-light-materials/src/camera.cpp

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+#include "camera.hpp"
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.hpp>
+
+glm::mat4 Camera::lookAt() {
+  return glm::lookAt(pos, pos + front, up);
+}
+
+void Camera::forward() {
+  pos += speed * front;
+}
+
+void Camera::back() {
+  pos -= speed * front;
+}
+
+void Camera::left() {
+  pos -= glm::normalize(glm::cross(front, up)) * speed;
+}
+
+void Camera::right() {
+  pos += glm::normalize(glm::cross(front, up)) * speed;
+}
+
+void Camera::update(float deltaTime) {
+  speed = 2.5f * deltaTime;
+}
+
+void Camera::mouse_move(double xpos, double ypos) {
+  if(firstMouse) {
+    lastX = xpos;
+    lastY = ypos;
+    firstMouse = false;
+  }
+
+  float xoffset = xpos - lastX;
+  float yoffset = lastY - ypos;
+  lastX = xpos;
+  lastY = ypos;
+
+  const float sensitivity = 0.1f;
+  xoffset *= sensitivity;
+  yoffset *= sensitivity;
+
+  yaw += xoffset;
+  pitch += yoffset;
+
+  if(pitch > 89.0f) pitch = 89.0f;
+  if(pitch < -89.0f) pitch = -89.0f;
+
+  direction.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
+  direction.y = sin(glm::radians(pitch));
+  direction.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
+
+  front = glm::normalize(direction);
+}
+
+void Camera::mouse_scroll(double xoffset, double yoffset) {
+  fov -= (float)yoffset;
+
+  if(fov < 1.0f) fov = 1.0f;
+  if(fov > 90.0f) fov = 90.0f;
+}

09-basic-light-materials/src/camera.hpp

@@ -0,0 +1,26 @@
+#pragma once
+#include <glm/glm.hpp>
+
+struct Camera {
+  glm::vec3 pos = glm::vec3(0.0f, 0.0f, 3.0f);
+  glm::vec3 front = glm::vec3(0.0f, 0.0f, -1.0f);
+  glm::vec3 up = glm::vec3(0.0f, 1.0f, 0.0f);
+  glm::vec3 direction = glm::vec3(0.0f, 0.0f, 0.0f);
+
+  float pitch = 0.0f;
+  float yaw = -90.0f;
+  float speed = 0.05f;
+  float lastX = 400;
+  float lastY = 300;
+  float fov = 45.0f;
+  bool firstMouse = true;
+
+  glm::mat4 lookAt();
+  void forward();
+  void back();
+  void left();
+  void right();
+  void update(float deltaTime);
+  void mouse_move(double xpos, double ypos);
+  void mouse_scroll(double xoffset, double yoffset);
+};

09-basic-light-materials/src/data.hpp

@@ -0,0 +1,46 @@
+#pragma once
+#include <glm/glm.hpp>
+
+float vertices[] = {
+    -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
+     0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f, 
+     0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f, 
+     0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f, 
+    -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f, 
+    -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f, 
+
+    -0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
+     0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
+     0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
+     0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
+    -0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
+    -0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
+
+    -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
+    -0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
+    -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
+    -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
+    -0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
+    -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
+
+     0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
+     0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
+     0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
+     0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
+     0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
+     0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
+
+    -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
+     0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
+     0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
+     0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
+    -0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
+    -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
+
+    -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
+     0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
+     0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
+     0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
+    -0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
+    -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f
+};

09-basic-light-materials/src/dbc.cpp

@@ -0,0 +1,47 @@
+#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);
+  }
+}

09-basic-light-materials/src/dbc.hpp

@@ -0,0 +1,46 @@
+#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());
+}

09-basic-light-materials/src/main.cpp

@@ -0,0 +1,319 @@
+#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>
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.hpp>
+#include "data.hpp"
+#include "physics.hpp"
+#include "model.hpp"
+#include "camera.hpp"
+
+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;
+  Shader light;
+  Model model;
+  glm::vec3 lightPos{1.2f, 1.0f, 2.0f};
+  glm::vec3 boxPos{2.0f, 0.0f, 0.0f};
+  unsigned int cubeVAO = 0;
+  unsigned int lightCubeVAO = 0;
+  unsigned int VBO = 0;
+  Camera camera{};
+  float deltaTime = 0.0f;
+  float lastFrame = 0.0f;
+
+  void updateDelta() {
+    float currentFrame = glfwGetTime();
+    deltaTime = currentFrame - lastFrame;
+    lastFrame = currentFrame;
+  }
+};
+
+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);
+}
+
+void mouse_callback(GLFWwindow *window, double xpos, double ypos) {
+  Camera* camera = static_cast<Camera*>(glfwGetWindowUserPointer(window));
+  camera->mouse_move(xpos, ypos);
+}
+
+void scroll_callback(GLFWwindow *window, double xoffset, double yoffset) {
+  Camera* camera = static_cast<Camera*>(glfwGetWindowUserPointer(window));
+  camera->mouse_scroll(xoffset, yoffset);
+}
+
+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");
+
+  glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
+  glfwSetCursorPosCallback(window, mouse_callback);
+  glfwSetScrollCallback(window, scroll_callback);
+
+  return window;
+}
+
+
+void processInput(GLFWwindow *window, BoxTest &box, Camera& camera) {
+
+  if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
+    glfwSetWindowShouldClose(window, true);
+  }
+
+  if(glfwGetKey(window, GLFW_KEY_SPACE) == GLFW_PRESS) {
+    b2Vec2 force(0.0f, 0.5f);
+    for(size_t i = 0; i < BODY_COUNT; i++) {
+      box.bodies[i]->ApplyForceToCenter(force, true);
+      box.bodies[i]->ApplyTorque(0.1f, true);
+    }
+  }
+
+  if(glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
+    camera.forward();
+  }
+
+  if(glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
+    camera.back();
+  }
+
+  if(glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
+    camera.left();
+  }
+
+  if(glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
+    camera.right();
+  }
+}
+
+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, rgb_or_a, width, height, 0, rgb_or_a, GL_UNSIGNED_BYTE, data);
+  glGenerateMipmap(GL_TEXTURE_2D);
+
+  stbi_image_free(data);
+
+  return texture_id;
+}
+
+Config setup() {
+  glEnable(GL_DEPTH_TEST);
+
+  Config config{
+    .shader={"shaders/08-vert.glsl", "shaders/08-frag.glsl"},
+    .light={"shaders/08-vert.glsl", "shaders/08-lightsource.frag.glsl"},
+    .model={"assets/popcorn_model_a.glb"}
+  };
+
+  unsigned int VBO = 0;
+  unsigned int lightCubeVAO = 0;
+  unsigned int cubeVAO = 0;
+
+  // cube vao configure, this is the light target
+  glGenVertexArrays(1, &cubeVAO);
+  glGenBuffers(1, &VBO);
+
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+  glBindVertexArray(cubeVAO);
+
+  // position attribute
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
+  glEnableVertexAttribArray(0);
+
+  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)(3 * sizeof(float)));
+  glEnableVertexAttribArray(1);
+
+  // light vao configure, this is the light source
+  glGenVertexArrays(1, &lightCubeVAO);
+  glBindVertexArray(lightCubeVAO);
+
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
+  glEnableVertexAttribArray(0);
+
+  config.lightCubeVAO = lightCubeVAO;
+  config.cubeVAO = cubeVAO;
+  config.VBO = VBO;
+
+  return config;
+}
+
+void draw_popcorn(Config& config, BoxTest& box, size_t box_i, glm::mat4& projection, glm::mat4& view)
+{
+  config.shader.use();
+  config.shader.setVec3("objectColor", 1.0f, 0.5f, 0.31f);
+  config.shader.setVec3("lightColor", 1.0f, 1.0f, 1.0f);
+  // THIS WAS MISSING
+  config.shader.setVec3("lightPos", config.lightPos);
+
+  config.shader.setMat4("view", view);
+  config.shader.setMat4("projection", projection);
+  config.shader.setVec3("viewPos", config.camera.pos);
+
+  float time = glfwGetTime();
+  // get position from box
+  b2Vec2 position = box.bodies[box_i]->GetPosition();
+  float angle = box.bodies[box_i]->GetAngle();
+
+  glm::mat4 model = glm::mat4(1.0f);
+  model = glm::translate(model, glm::vec3(position.x, position.y, 0.0f));
+
+  model = glm::rotate(model, angle / 5.0f, glm::vec3(1.0f, 0.0f, 0.0f));
+  model = glm::rotate(model, glm::radians(time * 10.0f), glm::vec3(0.0f, 1.0f, 1.0f));
+
+  config.shader.setMat4("model", model);
+
+  config.model.Draw(config.shader);
+}
+
+void draw_cube(Config& config, glm::mat4& projection, glm::mat4& view) {
+  config.shader.use();
+  config.shader.setVec3("objectColor", 1.0f, 0.5f, 0.31f);
+  config.shader.setVec3("lightColor", 1.0f, 1.0f, 1.0f);
+  // THIS WAS MISSING
+  config.shader.setVec3("lightPos", config.lightPos);
+
+  config.shader.setMat4("view", view);
+  config.shader.setMat4("projection", projection);
+  config.shader.setVec3("viewPos", config.camera.pos);
+
+  glm::mat4 model = glm::mat4(1.0f);
+  model = glm::translate(model, config.boxPos);
+  config.shader.setMat4("model", model);
+  glBindVertexArray(config.cubeVAO);
+  glDrawArrays(GL_TRIANGLES, 0, 36);
+}
+
+void draw_light(Config& config, glm::mat4& projection, glm::mat4& view) {
+  config.light.use();
+
+  config.light.setVec3("lightPos", config.lightPos);
+  config.light.setMat4("projection", projection);
+  config.light.setMat4("view", view);
+
+  glm::mat4 model = glm::mat4(1.0f);
+  model = glm::translate(model, config.lightPos);
+  model = glm::scale(model, glm::vec3(0.2f));
+  config.light.setMat4("model", model);
+
+  glBindVertexArray(config.lightCubeVAO);
+  glDrawArrays(GL_TRIANGLES, 0, 36);
+}
+
+
+void render(GLFWwindow* window, Config& config, BoxTest& box, b2World& world) {
+  glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+  config.shader.use();
+
+  Box2d_step_world(world);
+
+  // time is used for fake 3d rotation
+  float time = glfwGetTime();
+
+  config.camera.update(config.deltaTime);
+
+  glm::mat4 view = config.camera.lookAt();
+  glm::mat4 projection = glm::mat4(1.0f);
+  // fov, aspect, near plane, far plane
+  projection = glm::perspective(glm::radians(config.camera.fov), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
+
+  // update light color
+  draw_cube(config, projection, view);
+
+  // the 0 is for which popcorn, so later when we have N for-loop
+  draw_popcorn(config, box, 0, projection, view);
+
+  draw_light(config, projection, view);
+
+  glfwSwapBuffers(window);
+  glfwPollEvents();
+}
+
+void cleanup(Config& config) {
+  glDeleteVertexArrays(1, &config.lightCubeVAO);
+  glDeleteBuffers(1, &config.lightCubeVAO);
+  glDeleteBuffers(1, &config.VBO);
+  config.shader.cleanup();
+}
+
+int main() {
+  init_glfw();
+
+  b2Vec2 gravity(0.0f, -10.0f);
+  b2World world(gravity);
+  BoxTest box = Box2d_setup(world);
+
+  auto window = create_window();
+  auto config = setup();
+
+  glfwSetWindowUserPointer(window, &config.camera);
+
+  while(!glfwWindowShouldClose(window)) {
+    processInput(window, box, config.camera);
+    render(window, config, box, world);
+    config.updateDelta();
+  }
+
+  cleanup(config);
+
+  glfwTerminate();
+
+  return 0;
+}

09-basic-light-materials/src/mesh.cpp

@@ -0,0 +1,57 @@
+#include "mesh.hpp"
+
+void Mesh::Draw(Shader &shader) {
+  unsigned int diffuseNr = 1;
+  unsigned int specularNr = 1;
+  unsigned int normalNr = 1;
+  unsigned int heightNr = 1;
+
+  for(unsigned int i = 0; i < textures.size(); i++) {
+    glActiveTexture(GL_TEXTURE0 + i);
+    std::string number;
+    std::string name = textures[i].type;
+
+    if(name == "texture_diffuse") {
+      number = std::to_string(diffuseNr++);
+    } else if(name == "texture_specular") {
+      number = std::to_string(specularNr++);
+    } else if(name == "texture_normal") {
+      number = std::to_string(normalNr++);
+    } else if(name == "texture_height") {
+      number = std::to_string(heightNr++);
+    }
+
+    // TODO: Get this uniform ID once and cache it?
+    glUniform1i(glGetUniformLocation(shader.ID, (name + number).c_str()), i);
+    glBindTexture(GL_TEXTURE_2D, textures[i].id);
+  }
+
+  glBindVertexArray(VAO);
+  glDrawElements(GL_TRIANGLES, static_cast<unsigned int>(indices.size()), GL_UNSIGNED_INT, 0);
+  glBindVertexArray(0);
+
+  glActiveTexture(GL_TEXTURE0);
+}
+
+
+void Mesh::setupMesh() {
+  glGenVertexArrays(1, &VAO);
+  glGenBuffers(1, &VBO);
+  glGenBuffers(1, &EBO);
+
+  glBindVertexArray(VAO);
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+  glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), vertices.data(), GL_STATIC_DRAW);
+
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+  glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), indices.data(), GL_STATIC_DRAW);
+
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, Position));
+
+  glEnableVertexAttribArray(1);
+  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, Normal));
+
+  glEnableVertexAttribArray(2);
+  glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, TexCoords));
+}

09-basic-light-materials/src/mesh.hpp

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <glad/glad.h>
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+
+#include "shader.hpp"
+
+#include <string>
+#include <vector>
+
+struct Vertex {
+  glm::vec3 Position;
+  glm::vec3 Normal;
+  glm::vec2 TexCoords;
+};
+
+struct Texture {
+  unsigned int id;
+  std::string type;
+  std::string path;
+};
+
+struct Mesh {
+  std::vector<Vertex> vertices;
+  std::vector<unsigned int> indices;
+  std::vector<Texture> textures;
+  unsigned int VAO;
+  unsigned int VBO;
+  unsigned int EBO;
+
+  Mesh(std::vector<Vertex> vertices, std::vector<unsigned int> indices, std::vector<Texture> textures) :
+    vertices(vertices),
+    indices(indices),
+    textures(textures)
+  {
+    setupMesh();
+  }
+
+  void Draw(Shader &shader);
+  void setupMesh();
+};

09-basic-light-materials/src/model.cpp

@@ -0,0 +1,171 @@
+#include "model.hpp"
+#include "dbc.hpp"
+
+unsigned int TextureFromFile(const std::string& path, const std::string& directory, bool gamma)
+{
+  std::string filename = path + "/" + filename;
+
+  unsigned int textureID;
+  glGenTextures(1, &textureID);
+
+  int width = 0;
+  int height = 0;
+  int nrComponents = 0;
+
+  unsigned char *data = stbi_load(filename.c_str(), &width, &height, &nrComponents, 0);
+  dbc::check(data != nullptr, $F("Failed to load texture {}", filename));
+
+  GLenum format = GL_RGB;
+
+  if (nrComponents == 1) {
+    format = GL_RED;
+  } else if (nrComponents == 3) {
+    format = GL_RGB;
+  } else if (nrComponents == 4) {
+    format = GL_RGBA;
+  }
+
+  glBindTexture(GL_TEXTURE_2D, textureID);
+  glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
+  glGenerateMipmap(GL_TEXTURE_2D);
+
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+  stbi_image_free(data);
+
+  return textureID;
+}
+
+void Model::Draw(Shader &shader) {
+  for(unsigned int i = 0; i < meshes.size(); i++) {
+    meshes[i].Draw(shader);
+  }
+}
+
+void Model::loadModel(std::string path) {
+  Assimp::Importer importer;
+  const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_GenSmoothNormals | aiProcess_FlipUVs | aiProcess_CalcTangentSpace);
+
+  dbc::check(scene != nullptr, "Assimp ReadFile return null");
+  dbc::check(!(scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE), "Assimp says incomplete.");
+  dbc::check(scene->mRootNode != nullptr, "Assimp loaded scene doesn't have a root node");
+
+  directory = path.substr(0, path.find_last_of('/'));
+
+  processNode(scene->mRootNode, scene);
+}
+
+void Model::processNode(aiNode *node, const aiScene *scene) {
+  for(unsigned int i = 0; i < node->mNumMeshes; i++) {
+    aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
+    meshes.push_back(processMesh(mesh, scene));
+  }
+
+  for(unsigned int i = 0; i < node->mNumChildren; i++) {
+    processNode(node->mChildren[i], scene);
+  }
+}
+
+Mesh Model::processMesh(aiMesh *mesh, const aiScene *scene) {
+  std::vector<Vertex> vertices;
+  std::vector<unsigned int> indices;
+  std::vector<Texture> textures;
+
+  for(unsigned int i = 0; i < mesh->mNumVertices; i++) {
+    Vertex vertex;
+    vertex.Position = glm::vec3(
+      mesh->mVertices[i].x,
+      mesh->mVertices[i].y,
+      mesh->mVertices[i].z);
+
+    if(mesh->HasNormals()) {
+      vertex.Normal = glm::vec3(
+        mesh->mNormals[i].x,
+        mesh->mNormals[i].y,
+        mesh->mNormals[i].z);
+    }
+
+    if(mesh->mTextureCoords[0]) {
+      vertex.TexCoords = glm::vec2(
+          mesh->mTextureCoords[0][i].x,
+          mesh->mTextureCoords[0][i].y
+      );
+    } else {
+      vertex.TexCoords = glm::vec2(0.0f, 0.0f);
+    }
+
+    vertices.push_back(vertex);
+  }
+
+  for(unsigned int i = 0; i < mesh->mNumFaces; i++) {
+    aiFace face = mesh->mFaces[i];
+
+    for(unsigned int j = 0; j < face.mNumIndices; j++) {
+      indices.push_back(face.mIndices[j]);
+    }
+  }
+
+  aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
+
+  // we assume a convention for sampler names in the shaders. Each diffuse texture should be named
+  // as 'texture_diffuseN' where N is a sequential number ranging from 1 to MAX_SAMPLER_NUMBER.
+  // Same applies to other texture as the following list summarizes:
+  // diffuse: texture_diffuseN
+  // specular: texture_specularN
+  // normal: texture_normalN
+
+  // 1. diffuse maps
+  std::vector<Texture> diffuseMaps = loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");
+  textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
+
+  // 2. specular maps
+  std::vector<Texture> specularMaps = loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
+  textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
+
+  // 3. normal maps
+  std::vector<Texture> normalMaps = loadMaterialTextures(material, aiTextureType_HEIGHT, "texture_normal");
+  textures.insert(textures.end(), normalMaps.begin(), normalMaps.end());
+
+  // 4. height maps
+  std::vector<Texture> heightMaps = loadMaterialTextures(material, aiTextureType_AMBIENT, "texture_height");
+  textures.insert(textures.end(), heightMaps.begin(), heightMaps.end());
+
+  return Mesh(vertices, indices, textures);
+}
+
+std::vector<Texture> Model::loadMaterialTextures(aiMaterial *mat, aiTextureType type, std::string typeName)
+{
+  fmt::println("TEXTURE COUNT: {}, {}, {}", (int)type, typeName, mat->GetTextureCount(type));
+
+  std::vector<Texture> textures;
+  for(unsigned int i = 0; i < mat->GetTextureCount(type); i++) {
+    aiString str;
+    mat->GetTexture(type, i, &str);
+    std::string tx_str{str.C_Str()};
+
+    bool skip = false;
+    for(unsigned int j = 0; j < textures_loaded.size(); j++) {
+      if(textures_loaded[j].path == tx_str) {
+        textures.push_back(textures_loaded[j]);
+        skip = true;
+        break;
+      }
+    }
+
+    if(!skip) {
+      Texture texture{
+        .id = TextureFromFile(tx_str, directory),
+        .type = typeName,
+        .path = tx_str,
+      };
+
+      textures.push_back(texture);
+      textures_loaded.push_back(texture);
+    }
+  }
+
+  return textures;
+}

09-basic-light-materials/src/model.hpp

@@ -0,0 +1,40 @@
+#pragma once
+#include <glad/glad.h>
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <stb_image.h>
+#include <assimp/Importer.hpp>
+#include <assimp/scene.h>
+#include <assimp/postprocess.h>
+
+#include <mesh.hpp>
+#include <shader.hpp>
+
+#include <vector>
+#include <string>
+#include <fstream>
+#include <sstream>
+#include <iostream>
+#include <map>
+#include <vector>
+
+unsigned int TextureFromFile(const std::string& path, const std::string& directory, bool gamma = false);
+
+struct Model {
+  std::vector<Texture> textures_loaded;
+  std::vector<Mesh> meshes;
+  std::string directory;
+  bool gammaCorrection;
+
+  Model(const char *path) {
+    loadModel(path);
+  }
+
+  void Draw(Shader &shader);
+
+  void loadModel(std::string path);
+  void processNode(aiNode *node, const aiScene *scene);
+  Mesh processMesh(aiMesh *mesh, const aiScene *scene);
+
+  std::vector<Texture> loadMaterialTextures(aiMaterial *mat, aiTextureType type, std::string typeName);
+};

09-basic-light-materials/src/physics.cpp

@@ -0,0 +1,49 @@
+#include "physics.hpp"
+
+struct BoxTest Box2d_setup(b2World &world) {
+  BoxTest box;
+  float wall_x[4] = {0.0f, 0.0f, -0.99f, 0.99f};
+  float wall_y[4] = {-0.99, 0.99f, 0.0f, 0.0f};
+  float bound_w[4] = {1.0f, 1.0f, 0.1f, 0.1f};
+  float bound_h[4] = {0.1f, 0.1f, 1.0f, 1.0f};
+
+  for(size_t i = 0; i < 4; i++) {
+    b2BodyDef groundBodyDef;
+    groundBodyDef.position.Set(wall_x[i], wall_y[i]);
+    b2Body *groundBody = world.CreateBody(&groundBodyDef);
+
+    b2PolygonShape groundBox;
+    groundBox.SetAsBox(bound_w[i], bound_h[i]);
+    groundBody->CreateFixture(&groundBox, 1.0f);
+
+    box.walls[i] = groundBody;
+  }
+
+  for(size_t i = 0; i < BODY_COUNT; i++) {
+    b2BodyDef bodyDef;
+    bodyDef.type = b2_dynamicBody;
+    bodyDef.position.Set(0.0f, 0.5f);
+    box.bodies[i] = world.CreateBody(&bodyDef);
+
+    b2PolygonShape dynamicBox;
+    dynamicBox.SetAsBox(0.1f, 0.1f);
+    b2FixtureDef fixtureDef;
+    fixtureDef.shape = &dynamicBox;
+
+    fixtureDef.density = 1.0f;
+    fixtureDef.friction = 0.3f;
+
+    box.bodies[i]->CreateFixture(&fixtureDef);
+  }
+
+  return box;
+}
+
+void Box2d_step_world(b2World& world) {
+  float timeStep = 1.0f / 60.0f;
+  int velocityIterations = 6;
+  int positionIterations = 2;
+
+  // step the world
+  world.Step(timeStep, velocityIterations, positionIterations);
+}

09-basic-light-materials/src/physics.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <box2d/box2d.h>
+
+#define BODY_COUNT 1
+
+struct BoxTest {
+  b2Body *walls[4];
+  b2Body *bodies[BODY_COUNT];
+};
+
+struct BoxTest Box2d_setup(b2World &world);
+void Box2d_step_world(b2World& world);

09-basic-light-materials/src/shader.cpp

@@ -0,0 +1,126 @@
+#include "shader.hpp"
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <print>
+#include <filesystem>
+#include "dbc.hpp"
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.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);
+}
+
+void Shader::setVec4(const std::string &name, const glm::vec4& value) const
+{
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform4fv(uniform, 1, &value[0]);
+}
+
+void Shader::setVec3(const std::string &name, const glm::vec3& value) const
+{
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform3fv(uniform, 1, &value[0]);
+}
+
+void Shader::setVec3(const std::string &name, float v1, float v2, float v3) const {
+  auto uniform = glGetUniformLocation(ID, name.c_str());
+  glUniform3f(uniform, v1, v2, v3);
+}
+
+void Shader::setMat4(const std::string &name, const glm::mat4& mat) const {
+  unsigned int loc = glGetUniformLocation(ID, name.c_str());
+  glUniformMatrix4fv(loc, 1, GL_FALSE, glm::value_ptr(mat));
+}

09-basic-light-materials/src/shader.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <glad/glad.h>
+#include <string>
+#include <climits>
+#include <glm/glm.hpp>
+
+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 setVec4(const std::string &name, const glm::vec4& value) const;
+  void setVec3(const std::string &name, float v1, float v2, float v3) const;
+  void setVec3(const std::string &name, const glm::vec3& value) const;
+  void setMat4(const std::string &name, const glm::mat4& what) const;
+  void cleanup();
+};

09-basic-light-materials/src/stb_image.cpp

@@ -0,0 +1,2 @@
+#define STB_IMAGE_IMPLEMENTATION
+#include <stb_image.h>