#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
//函数声明
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);
// settings
//定义窗口宽度与高度
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
int main()
{
// glfw: initialize and configure
// ------------------------------
glfwInit();//初始化GLFW
// 名称 版本号
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);//配置GLFW
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
// glfw window creation
// --------------------
//创建窗口
GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
//失败处理
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
//注册窗口回调函数
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
// glad: load all OpenGL function pointers
// ---------------------------------------
//GLAD管理OpenGL的函数指针
//初始化GLAD
//glfwGetProcAddress 函数指针
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
// render loop
// -----------
//循环渲染:主动关闭前不断绘制图像
//glfwWindowShouldClose(window):检查是否要求退出
while (!glfwWindowShouldClose(window))
{
// input
// -----
//调用检测用户输入函数
processInput(window);
// render
// ------
//以一个自定义颜色清空屏幕
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);//设置清空屏幕的颜色
glClear(GL_COLOR_BUFFER_BIT);//清空屏幕,有三个可选参数值
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
//存储窗口中每一个像素的颜色值的大缓冲
//交换缓冲:交换前缓冲和后缓冲,双缓冲技术
glfwSwapBuffers(window);
//检查用户事件,并调用相应函数;此处无调用。
glfwPollEvents();
}
// glfw: terminate, clearing all previously allocated GLFW resources.
// ------------------------------------------------------------------
//清理资源
glfwTerminate();
return 0;
}
// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
//获取用户输入
void processInput(GLFWwindow *window)
{
if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
// glfw: whenever the window size changed (by OS or user resize) this callback function executes
//回调函数,在窗口大小被调整时调用
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
// make sure the viewport matches the new window dimensions; note that width and
// height will be significantly larger than specified on retina displays.
//设置窗口维度
//坐标系不同??
glViewport(0, 0, width, height);
}
LearnOpenGL代码注释-你好,窗口
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转载自blog.csdn.net/qq_33446100/article/details/82778953
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