OpenGL 编程/中级/细分多边形

#include <GL/glut.h>

void init(){ 
    glClearColor(0,0,0,0);
    glMatrixMode(GL_PROJECTION);
    gluOrtho2D(0,100,0,200);
}
void Display(){
     glClear(GL_COLOR_BUFFER_BIT);
     glBegin(GL_TRIANGLE_FAN);
         glColor3f(1,0,0);
         glVertex2f(0,0.5);
         glVertex2f(-0.4,0);
 	 glVertex2f(0.4,0);
         glColor3f(0,1,0);
 	 glVertex2f(0,-0.5);
     glEnd();
     glFlush(); 
} 

int main(int argc, char **argv){ 	
    glutInit(& argc, argv);
    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
    glutInitWindowSize(500,500);
    glutInitWindowPosition(200,200);
    glutCreateWindow("line");
    glutDisplayFunc(Display);
    init();
    glutMainLoop();
	
    return 0;
}