/*
Problem Statement: a) Write C++ program to draw the following pattern. Use DDA line and Bresenham's circle drawing algorithm. Apply the concept of encapsulation.
Code from Computer Graphics (SPPU - Second Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-se-comp-codes/CG
*/

// BEGINNING OF CODE
#include <iostream>
#include <graphics.h>
#include <math.h>
using namespace std;

void bresenhamCircle(int xcord, int ycord, int rad) {
// function to create circle using Bresenham algorithm
	int dec, x, y;
	dec = 3-2*rad; // dec is the decision parameter
	x = 0;
	y = rad; // set y equals to radius

	while (y >= x) {
		putpixel(xcord+x, ycord+y, 15); // bottom right
		putpixel(xcord+y, ycord+x, 15); // right side
		putpixel(xcord+y, ycord-x, 15); // right up
		putpixel(xcord+x, ycord-y, 15); // top
		putpixel(xcord-x, ycord-y, 15); // left top
		putpixel(xcord-y, ycord-x, 15); // left side
		putpixel(xcord-y, ycord+x, 15); // left bottom
		putpixel(xcord-x, ycord+y, 15); // bottom
		x++;
		// note: 15 is the colour, instead you can also put WHITE, RED, GREEN, etc.

		// decision paramter
		if (dec > 0 ) {
			y--;
			dec = dec+4*(x-y)+10;
		}
		else {
			dec = dec+4*x+6;
		}
	// delay(10); // optional delay to watch the circle being made
	}
}

void ddaLine(float x1, float y1, float x2, float y2) {
// DDA line drawing algorithm (will be used for triangle)
	float dx, dy, steps, xinc, yinc, x, y;

	dx = abs(x2-x1);
	dy = abs(y2-y1);

	if (dx>dy) {
		steps = dx;
	}
	else {
		steps = dy;
	}

	xinc = (x2-x1)/steps;
	yinc = (y2-y1)/steps;

	x = x1;
	y = y1;
	putpixel(round(x), round(y), 15);

	for (int i=0; i<steps; i++) {
		x = x + xinc;
		y = y + yinc;
		putpixel(round(x), round(y), 15);
	}
}

int main() {
	float x1, y1, x2, y2, x3; // variables to store line coordinates
	int x, y, r; // variables to store circle coordinates

	cout<<endl<<"Enter coordinates:";
	cout<<endl<<"Enter value for X1:\t";
	cin>>x1;
	cout<<endl<<"Enter value for Y1:\t";
	cin>>y1;
	cout<<endl<<"Enter value for X2:\t";
	cin>>x2;

	// calculating values for x3 and y2 for triangle
	x3 = (x2+x1)/2;
	y2 = y1 - sqrt(pow((x2-x1), 2) - pow((x2-x1)/2, 2));

	// initializing graphics window
	int gd=DETECT, gm;
	initgraph(&gd, &gm, NULL);

	// make triangle
		ddaLine(x1, y1, x2, y1);
		ddaLine(x2, y1, x3, y2);
		ddaLine(x3, y2, x1, y1);

	// make inner circle
		x = x3;
		y = y2+2*(y1-y2)/3;
		r = (y1-y2)/3;
		bresenhamCircle(x,y,r);

	// make outer circle
		r = 2*(y1-y2)/3; // instead you can also use "r=2*r", it's the same
		bresenhamCircle(x,y,r);

	delay(50000);
	closegraph();
	return 0;
}
// END OF CODE