使用现代OpenGL绘制三角形

没有shader的版本

#include<GL/glew.h>//glew必须在glfw前
#include <GLFW/glfw3.h>

#include<iostream>

int main(void)
{
    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
        return -1;

    glewInit();

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "OpenGl", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }

    /* Make the window's context current */
    glfwMakeContextCurrent(window);

    //---此后才有有效的渲染环境---

    if (glewInit() != GLEW_OK) {//检测
        std::cout << "Error" << std::endl;
    }
    std::cout << glGetString(GL_VERSION) << std::endl;

    float position[6] = {
        -0.5f, -0.5f,
         0.0f,  0.5f,
         0.5f, -0.5f
    };
    
    unsigned int buffer;
    glGenBuffers(1, &buffer);
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glBufferData(GL_ARRAY_BUFFER,sizeof(position),position,GL_STATIC_DRAW);

    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);

    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        /* Render here */
        glClear(GL_COLOR_BUFFER_BIT);

        glDrawArrays(GL_TRIANGLES,0,3);

        /* Swap front and back buffers */
        glfwSwapBuffers(window);

        /* Poll for and process events */
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}