justhomework/OpenGL/hello/src/main.cpp

#include "source.h"

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void processInput(GLFWwindow *window);
void mouse_callback(GLFWwindow *window, double xpos, double ypos);
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);

int main() {

  // 设置 glfw
  glfwInit();
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  // glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);

  // 创建窗口
  GLFWwindow *window =
      glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
  if (window == NULL) {
    std::cout << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }
  glfwMakeContextCurrent(window);

  // 加载glad
  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
    std::cout << "Failed to initialize GLAD" << std::endl;
    return -1;
  }

  // 设置视口
  glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
  glfwSetCursorPosCallback(window, mouse_callback);
  glfwSetScrollCallback(window, scroll_callback);

  // 创建着色器程序
  Shader shader = Shader("src/cube.vs", "src/cube.fs");
  Shader lightShader = Shader("src/light.vs", "src/light.fs");

  unsigned int VAO, VBO, EBO;
  // 创建顶点数组对象
  glGenVertexArrays(1, &VAO);
  glBindVertexArray(VAO);

  // 创建顶点缓冲对象
  glGenBuffers(1, &VBO);
  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

  // 顶点属性
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
  glEnableVertexAttribArray(0);

  // 法向量属性
  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float),
                        (void *)(3 * sizeof(float)));
  glEnableVertexAttribArray(1);

  // 设置光源
  unsigned int lightVAO;
  glGenVertexArrays(1, &lightVAO);
  glBindVertexArray(lightVAO);
  // 只需要绑定VBO不用再次设置VBO的数据，因为箱子的VBO数据中已经包含了正确的立方体顶点数据
  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  // 设置灯立方体的顶点属性（对我们的灯来说仅仅只有位置数据）
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
  glEnableVertexAttribArray(0);

  // 开启深度测试
  glEnable(GL_DEPTH_TEST);

  // 循环渲染
  while (!glfwWindowShouldClose(window)) {

    // 计算帧时间差
    float currentFrame = glfwGetTime();
    deltaTime = currentFrame - lastFrame;
    lastFrame = currentFrame;

    // 处理输入
    processInput(window);

    // 设置为白色
    glClearColor(0.1f, 0.1f, 0.1f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    lightPos.x = 1.0f + sin(glfwGetTime()) * 2.0f;
    lightPos.y = sin(glfwGetTime() / 2.0f) * 1.0f;

    glm::mat4 view = camera.GetViewMatrix();
    glm::mat4 projection =
        glm::perspective(glm::radians(camera.Zoom),
                         (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
    glm::mat4 model = glm::mat4(1.0f);

    // 绘制三角形
    shader.use();
    shader.setVec3("objectColor", 1.0f, 0.5f, 0.31f);
    shader.setVec3("lightColor", 1.0f, 1.0f, 1.0f);
    shader.setVec3("lightPos", lightPos);
    shader.setVec3("viewPos", camera.Position);
    shader.setMat4("model", model);
    shader.setMat4("projection", projection);
    shader.setMat4("view", view);
    glBindVertexArray(VAO);
    glDrawArrays(GL_TRIANGLES, 0, 36);

    model = glm::mat4(1.0f);
    model = glm::translate(model, lightPos);
    model = glm::scale(model, glm::vec3(0.2f)); // a smaller cube

    lightShader.use();
    lightShader.setMat4("projection", projection);
    lightShader.setMat4("view", view);
    lightShader.setMat4("model", model);

    glBindVertexArray(lightVAO);
    glDrawArrays(GL_TRIANGLES, 0, 36);

    // 检查并调用事件，交换缓冲
    glfwSwapBuffers(window);
    glfwPollEvents();
  }

  // 释放资源
  glfwTerminate();
  return 0;
}

// 处理输入
void processInput(GLFWwindow *window) {
  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    glfwSetWindowShouldClose(window, true);
  if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
    camera.ProcessKeyboard(FORWARD, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
    camera.ProcessKeyboard(BACKWARD, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    camera.ProcessKeyboard(LEFT, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
    camera.ProcessKeyboard(RIGHT, deltaTime);
}

// 窗口大小改变时回调该函数
void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
  glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow *window, double xpos, double ypos) {
  camera.ProcessMouseMovement(xpos, ypos);
}

void scroll_callback(GLFWwindow *window, double xoffset, double yoffset) {
  camera.ProcessMouseScroll(yoffset);
}