#if !defined(Linux)
  #include <windows.h>           //Not Linux must be windows
#endif
#include <stdio.h>
#include <GL/gl.h>
#include <glut.h>
#include <math.h>

#define RANDOM(M) ((float)rand()/RAND_MAX*(M));

/* Author: Brian J. Ross
   November 2015             

   Draw Sierpinski Triangles using IFS algorithm. */


void drawtri(void) {
	int i, j;
	float r;

	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1.0, 1.0, 1.0);

	for (i=0; i < 100000; i++) {
		glLoadIdentity();
		for (j = 0; j < 10; j++) {
			r = (float)rand()/RAND_MAX;
			if (r < 0.33) {
				glTranslatef(-40.0, -40.0, 0.0);
				glScalef(0.5, 0.5, 1.0);
			}
			else if (r < 0.67) {
				glTranslatef(40.0, -40.0, 0.0);
				glScalef(0.5, 0.5, 1.0);
			}
			else {
				glTranslatef(0.0, 40.0, 0.0);
				glScalef(0.5, 0.5, 1.0);
			};
		}; // j

		glBegin(GL_POINTS);
		   glVertex2d((float)rand()/RAND_MAX*(600.0)-300.0, (float)rand()/RAND_MAX*(600.0)-300.0);
		glEnd();
	}; // i

	glFlush(); 
}


main(int argc, char **argv) {
	glutInit(&argc, argv);
	glutInitWindowSize(600, 600);
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutCreateWindow("Sierpinski Triangles");

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(-100.0, 100.0, -100.0, 100.0);
       
	glMatrixMode(GL_MODELVIEW);

	glClearColor(0.0, 0.0, 0.0, 1.0);  /* black */

	glutDisplayFunc(drawtri);
	glutMainLoop();
	return 0;
}