(四)opengl函数加载和错误处理

#include <glad/glad.h>//glad必须在glfw头文件之前包含
#include <GLFW/glfw3.h>
#include <iostream>void frameBufferSizeCallbakc(GLFWwindow* window, int width, int height)
{glViewport(0, 0, width, height);std::cout << width << "," << height << std::endl;
}
void glfwKeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
{}
int main()
{//初始化glfw环境glfwInit();//设置opengl主版本号glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR,3);//设置opengl次版本号glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);//设置opengl启用核心模式glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);//创建窗体对象GLFWwindow* window = glfwCreateWindow(800, 600, "lenarnOpenGL", nullptr, nullptr);//设置当前窗体对象为opengl的绘制舞台glfwMakeContextCurrent(window);//窗体大小回调glfwSetFramebufferSizeCallback(window, frameBufferSizeCallbakc);//键盘相应回调glfwSetKeyCallback(window, glfwKeyCallback);//使用glad加载所有当前版本opengl的函数if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){std::cout << "初始化glad失败" << std::endl;return -1;}//设置opengl视口大小和清理颜色glViewport(0, 0, 800, 600);glClearColor(0.2f, 0.3f, 0.3f, 1.0f);//执行窗体循环while (!glfwWindowShouldClose(window)){//接受并分发窗体消息//检查消息队列是否有需要处理的鼠标、键盘等消息//如果有的话就将消息批量处理，清空队列glfwPollEvents();//执行opengl画布清理操作glClear(GL_COLOR_BUFFER_BIT);//渲染操作//切换双缓存glfwSwapBuffers(window);}//推出程序前做相关清理glfwTerminate();return 0;
}

使用gladLoadGLLoader函数可以加载opengl中所有的函数。
glGetError函数可以获取上行代码是否报错以及错误信息：

#include <assert.h>
void checkError() {GLenum errorCode = glGetError();std::string error = "";if (errorCode != GL_NO_ERROR) {switch (errorCode){case GL_INVALID_ENUM: error = "INVALID_ENUM"; break;case GL_INVALID_VALUE:  error = "INVALID_VALUE"; break;case GL_INVALID_OPERATION: error = "INVALID_OPERATION"; break;case GL_OUT_OF_MEMORY: error = "OUT OF MEMORY"; break;default:error = "UNKNOWN";break;}std::cout << error << std::endl;//assert会根据传入的bool值，来决定程序是否停止//true：程序顺利运行//false：程序会断死assert(false);}
}