OpenGL基于glfw库的画点、画线、画三角

#include <GLFW/glfw3.h>
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;
}