#include <gl\glut.h>
#include <stdlib.h>


typedef struct {
	float x;
	float y;
	float z;
} point3;

    point3 vertices[4]={{0.0,0.0, 0.0},{250.0,500.0, 	100.0},{500.0,0.0,0.0},{250.0, 250.0, 250.0}};
	int j;
	point3 new_p, old={250,100,250};

	void clear(void){
          glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
	}

	void display( void ){
	j=rand()%4; /* pick a vertex at random */
	new_p.x=(old.x+vertices[j].x)/2;
	new_p.y=(old.y+vertices[j].y)/2;
	new_p.z=(old.z+vertices[j].z)/2;
    glBegin(GL_POINTS);
	glColor3f(1.0-new_p.z/250.,new_p.z/250.0, 0.0);
    glVertex3f(new_p.x,new_p.y,new_p.z); 
    glEnd();
    old.x=new_p.x;
	old.y=new_p.y;
	old.z=new_p.z;
    glFlush();  
	}
void init(){
	glClearColor(1.0, 1.0, 1.0, 1.0); /* white background */
    glColor3f(1.0, 0.0, 0.0); /* draw in red */
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.0, 500.0, 0.0, 500.0, -500.0, 500.0);
     glMatrixMode(GL_MODELVIEW); 
}
void mouse(int btn, int state, int x, int y){/*¸¶¿ì½º ¿Þ/¿À¸¥¹öÆ°, ´©¸§»óÅÂ, ÁÂÇ¥x, ÁÂÇ¥y*/
	if((btn==GLUT_LEFT_BUTTON) & (state==GLUT_DOWN)) glutIdleFunc(display);
	if((btn==GLUT_RIGHT_BUTTON) & (state==GLUT_DOWN)) glutIdleFunc(NULL);

}
void main(int argc, char** argv){
    glutInit(&argc,argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB |GLUT_DEPTH);
    glutInitWindowSize(500,500); /* 500 x 500 pixel window */
    glutInitWindowPosition(0,0); /* place window top left on display */
    glutCreateWindow("Sierpinski Gasket"); /* window title */
    glutDisplayFunc(clear);
	init();
    glutIdleFunc(display); /* display callback invoked when window opened */
    glutMouseFunc(mouse);// 
	glEnable(GL_DEPTH_TEST); /*µÚ¿¡ ¸¸µé¾îÁö´Â°ÍÀÌ ¾È º¸ÀÌ°Ô Çϱâ À§ÇÔ*/
    glutMainLoop();
}