Sierpinski Ext

/*
 * File: Sierpinski.cpp
 * --------------------------
 * Name: Ana Gurgenidze
 * Section: #2, Michael Nemsitsveridze
 * This file is the final project for the Sierpinski problem
 * on Assignment #3.
 * The program draws Sierpinski triangle.
 */

#include <iostream>
#include "gwindow.h"
#include <cmath>
using namespace std;

void drawSierpinski(double lng, int rank, double x, double y, GWindow &gw, int &index);

/* draws single triangle */
void makeLine(double size, double x, double y, GWindow &gw, int &index) {
	double theta = index * 45;
	GPoint p1 = gw.drawPolarLine(x, y, size, theta);
}

int main() {
    GWindow gw;
	double lng; // length of the starting triangle
	int rank; // Sierpinski triangle level
	cin >> lng >> rank;
	double x = gw.getWidth() / 2; // starting X coordinate
	double y = gw.getHeight(); // starting Y coordinate
	int start = 2;
	drawSierpinski(lng, rank, x, y, gw, start);
    return 0;
}

/* Recursive function that draws Sierpinski triangle */
void drawSierpinski(double lng, int rank, double x, double y, GWindow &gw, int &index) {
	int i = (index + 1) % 8;
	int j = abs(index - 1) % 8;
	if (rank == 0) {
		makeLine(lng, x, y, gw, index);
	} else {
		switch (index) {
			case 0:
				x += lng;
				break;
			case 1:
				x += lng * sqrt(2.0);
				y -= lng * sqrt(2.0);
				break;
			case 2:
				y -= lng;
				break;
			case 3:
				x -= lng * sqrt(2.0);
				y -= lng * sqrt(2.0);
				break;
			case 4:
				x -= lng;
				break;
			case 5:
				x -= lng * sqrt(2.0);
				y += lng * sqrt(2.0);
				break;
			case 6:
				y += lng;
				break;
			default:
				x += lng * sqrt(2.0);
				y += lng * sqrt(2.0);
		}
		lng /= 2;
		rank --;
		drawSierpinski(lng, rank, x, y, gw, i);
		drawSierpinski(lng, rank, x, y, gw, j);
	}
}