opengl 绘制简单图形

#include <gl/glut.h>

void display()
{
glClear(GL_COLOR_BUFFER_BIT);

/*
glBegin(GL_POLYGON);
glVertex2f(-0.5,-0.5);
glVertex2f(-0.5,0.5);
glVertex2f(0.5,0.5);
glVertex2f(0.5,-0.5);
glEnd();
*/

glPointSize(5.0);
glBegin(GL_POINTS);
glColor3f(1.0,1.0,1.0);
glVertex2f(-0.5,-0.5);
glColor3f(1.0,0.0,0.0);
glVertex2f(-0.5,0.5);
glColor3f(0.0,0.0,1.0);
glVertex2f(0.5,0.5);
glColor3f(0.0,1.0,0.0);
glVertex2f(0.5, -0.5);
glEnd();

glBegin(GL_LINES);
glVertex2f(-0.5,-0.5);
glVertex2f(-0.5,0.5);
glVertex2f(0.5,0.5);
glVertex2f(0.5,-0.5);
glEnd();

glBegin(GL_LINE_STRIP);
glVertex2f(-0.5,-0.5);
glVertex2f(-0.5,0.5);
glVertex2f(0.5,0.5);
glVertex2f(0.5,-0.5);
glEnd();

glBegin(GL_LINE_LOOP);
glVertex2f(-0.5,-0.5);
glVertex2f(-0.5,0.5);
glVertex2f(0.5,0.5);
glVertex2f(0.5,-0.5);
glEnd();

glBegin(GL_TRIANGLES);
glVertex2f(-0.5,-0.5);
glVertex2f(-0.5,0.5);
glVertex2f(0.5,0.5);
glEnd();

glBegin(GL_TRIANGLE_STRIP);
glColor3f(1.0,1.0,0.0);
glVertex2f(0.5,-0.5);
glColor3f(1.0,0.0,1.0);
glVertex2f(-0.5,0.5);
glColor3f(0.0,0.0,0.0);
glVertex2f(0.5,0.5);
glEnd();

glColor3f(0.0,0.0,1.0);
glBegin(GL_TRIANGLE_FAN);
glVertex2f(0.5,-0.5);
glVertex2f(0.5,0.5);
glVertex2f(-0.5,0.5);
glEnd();

glFlush();
}

void init()
{
glClearColor(0.0,0.0,0.0,0.0);
glColor3f(1.0,1.0,1.0);

glEnable(GL_LINE_STIPPLE);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
glShadeModel(GL_SMOOTH);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(-2.0,2.0,-2.0,2.0);
}

int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutInitWindowSize(500,500);
glutInitWindowPosition(100,100);
glutCreateWindow("simple");
glutDisplayFunc(display);

init();
glutMainLoop();

return 0;
}