OpenGL基于glfw库的画点、画线、画三角

1)glVertex函数

参考：http://www.cnblogs.com/mattins/articles/4081970.html

2）坐标系

http://blog.csdn.net/meegomeego/article/details/8686816

代码如下：

#include 
void drawPoint()
{
    /* Draw a point */
    glClearColor (0.0, 0.0, 0.0, 0.0); 
    glClear(GL_COLOR_BUFFER_BIT);
        
    glPointSize(2.0f);
    glBegin(GL_POINTS);

    glColor3f(1.0, 0.0, 0.0);    // Red
    glVertex2f(0.0f,0.0f);
    glVertex2f(0.5f,0.8f);
    glEnd();
}
void drawLint()
{
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glClear (GL_COLOR_BUFFER_BIT);

    glLineWidth(2);//设置线段宽度
    glBegin(GL_LINES);
    glColor3f(1.0,0.0,0.0);
    glVertex2f(0.8,1); //定点坐标范围

    glVertex2f(0,-1);
    glEnd();
}
void drawTriangle()
{
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glClear (GL_COLOR_BUFFER_BIT);
    glBegin(GL_TRIANGLES);

    glColor3f(1.0, 0.0, 0.0);    // Red
    glVertex3f(0.0, 1.0, 0.0);

    glColor3f(0.0, 1.0, 0.0);    // Green
    glVertex3f(-1.0, -1.0, 0.0);

    glColor3f(0.0, 0.0, 1.0);    // Blue
    glVertex3f(1.0, -1.0, 0.0);
    glEnd();
}
int main(void)
{
    GLFWwindow* window;

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

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(480, 320, "Hello World", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }

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

    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        
        /*your draw*/
        // drawPoint();
        // drawLint();
        drawTriangle();

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

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

    glfwTerminate();
    return 0;
}

运行一下！

参考：

OpenGL简单画线程序

GLFW初体验

OpenGL绘制点

GLFW--Getting started