main.cpp

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <tool/shader.h>
#include <iostream>

#define STB_IMAGE_IMPLEMENTATION
#include <tool/stb_image.h>

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void processInput(GLFWwindow *window);
std::string Shader::dirName;

using namespace std;

int main(int argc, char *argv[])
{
  Shader::dirName = argv[1];
  glfwInit();
  // 设置主要和次要版本
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

  // 创建窗口对象
  GLFWwindow *window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
  if (window == NULL)
  {
    std::cout << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }
  glfwMakeContextCurrent(window);

  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
  {
    std::cout << "Failed to initialize GLAD" << std::endl;
    return -1;
  }
  // 设置视口
  glViewport(0, 0, 800, 600);
  glEnable(GL_PROGRAM_POINT_SIZE);

  // 注册窗口变化监听
  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

  Shader ourShader("./shader/vertex.glsl", "./shader/fragment.glsl");

  // 顶点数据
  float vertices[] = {
      //     ---- 位置 ----       ---- 颜色 ----     - 纹理坐标 -
      0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f,  // 右上
      0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // 右下
      -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0, 0.0f, // 左下
      -0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f  // 左上
  };

  // 索引数据
  unsigned int indices[] = {
      0, 1, 3, // 三角形一
      1, 2, 3  // 三角形二
  };

  // 创建缓冲对象
  unsigned int VBO, EBO, VAO;
  glGenVertexArrays(1, &VAO);
  glGenBuffers(1, &VBO);
  glGenBuffers(1, &EBO);

  // 绑定VAO缓冲对象
  glBindVertexArray(VAO);

  // 绑定VBO缓对象
  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  // 填充VBO数据
  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);

  // 设置顶点位置属性指针
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
  glEnableVertexAttribArray(0);

  // 设置顶点颜色属性指针
  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(3 * sizeof(float)));
  glEnableVertexAttribArray(1);

  // 设置顶点纹理坐标属性指针
  glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(6 * sizeof(float)));
  glEnableVertexAttribArray(2);

  glBindVertexArray(0);

  // 生成纹理
  unsigned int texture1, texture2;
  glGenTextures(1, &texture1);
  glBindTexture(GL_TEXTURE_2D, texture1);

  // 设置环绕和过滤方式
  float borderColor[] = {0.3f, 0.1f, 0.7f, 1.0f};
  glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);

  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_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  // 图像y轴翻转
  stbi_set_flip_vertically_on_load(true);

  // 加载图片
  int width, height, nrChannels;
  unsigned char *data = stbi_load("./static/texture/container.jpg", &width, &height, &nrChannels, 0);

  if (data)
  {
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);
  }
  stbi_image_free(data);

  glGenTextures(1, &texture2);
  glBindTexture(GL_TEXTURE_2D, texture2);

  // 设置环绕和过滤方式
  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_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  // 加载图片
  data = stbi_load("./static/texture/awesomeface.png", &width, &height, &nrChannels, 0);

  if (data)
  {
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);
  }
  stbi_image_free(data);
  ourShader.use();
  ourShader.setInt("texture1", 0);
  ourShader.setInt("texture2", 1);

  float factor = 0.0;

  while (!glfwWindowShouldClose(window))
  {
    processInput(window);

    // 渲染指令
    // ...
    glClearColor(25.0 / 255.0, 25.0 / 255.0, 25.0 / 255.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    ourShader.use();

    factor = glfwGetTime();
    ourShader.setFloat("factor", factor);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture1);

    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, texture2);

    glBindVertexArray(VAO);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    glfwSwapBuffers(window);
    glfwPollEvents();
  }

  glDeleteVertexArrays(1, &VAO);
  glDeleteBuffers(1, &VBO);
  glDeleteBuffers(1, &EBO);

  glfwTerminate();
  return 0;
}

void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
  glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window)
{
  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
  {
    glfwSetWindowShouldClose(window, true);
  }
}