From a71700e42b40386f55ee43006f003d8d47576dc8 Mon Sep 17 00:00:00 2001
From: Kshitij <kshitijk@tuta.io>
Date: Tue, 5 Dec 2023 16:05:49 +0530
Subject: [PATCH] simplified code for assignment 3 (a and b), added explanation
 for some stuff and added 3b (earlier only 3a was there)

---
 ... using DDA and Bresenham Line Drawing).cpp |  97 ---------------
 ...A Line and Bresenham Circle Algorithm).cpp | 103 ++++++++++++++++
 ...A Line and Bresenham Circle Algorithm).cpp | 111 ++++++++++++++++++
 README.md                                     |  17 +--
 4 files changed, 223 insertions(+), 105 deletions(-)
 delete mode 100644 Assignment A-3 (Pattern using DDA and Bresenham Line Drawing).cpp
 create mode 100755 Assignment A-3a (Pattern using DDA Line and Bresenham Circle Algorithm).cpp
 create mode 100755 Assignment A-3b (Pattern using DDA Line and Bresenham Circle Algorithm).cpp

diff --git a/Assignment A-3 (Pattern using DDA and Bresenham Line Drawing).cpp b/Assignment A-3 (Pattern using DDA and Bresenham Line Drawing).cpp
deleted file mode 100644
index 145eec1..0000000
--- a/Assignment A-3 (Pattern using DDA and Bresenham Line Drawing).cpp	
+++ /dev/null
@@ -1,97 +0,0 @@
-/*
-Problem Statement: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 <bits/stdc++.h>
-using namespace std;
-
-class algo {
-	public:
-		void dda_line(float x1, float y1, float x2, float y2);
-		void bresneham_cir(int r);
-};
-
-void algo::dda_line(float x1, float y1, float x2, float y2) {
-	float x,y,dx,dy,step;
-	int i;
-	//step 2
-	dx=abs(x2-x1);
-	dy=abs(y2-y1);
-	cout<<"dy="<<dy<<"\tdx="<<dx;
-	//step 3
-	if(dx>=dy)
-		step=dx;
-	else
-		step=dy;
-	cout<<"\n"<<step<<endl;
-	//step 4
-	float xinc=float((x2-x1)/step);
-	float yinc=float((y2-y1)/step);
-	//step 5
-	x=x1;
-	y=y1;
-	// outtextxy(0,0,"(0,0)");
-	//step 6
-	i=1;
-	while(i<=step) {
-		// cout<<endl<<"\t"<<i<<"\t(x,y)=("<<x<<","<<y<<")";
-		putpixel(320+x,240-y,4);
-		x=x+xinc;
-		y=y+yinc;
-		i=i+1;
-		// delay(10);
-	}
-}
-
-void algo::bresneham_cir(int r) {
-	float x,y,p;
-	x=0;
-	y=r;
-	p=3-(2*r);
-	while(x<=y) {
-		putpixel(320+x,240+y,1);
-		putpixel(320-x,240+y,2);
-		putpixel(320+x,240-y,3);
-		putpixel(320-x,240-y,5);
-		putpixel(320+y,240+x,6);
-		putpixel(320+y,240-x,7);
-		putpixel(320-y,240+x,8);
-		putpixel(320-y,240-x,9);
-		x=x+1;
-		if(p<0) {
-			p=p+4*(x)+6;
-		}
-		else {
-			p=p+4*(x-y)+10;
-			y=y-1;
-		}
-	// delay(20);
-	}
-}
-
-int main() {
-	algo a1;
-	int i;
-	float r,ang,r1;
-	initwindow(630,480);
-	cout<<"Enter radius of circle";
-	cin>>r;
-	a1.bresneham_cir((int)r);
-	ang=3.24/180;
-	float c=r*cos(30*ang);
-	float s=r*sin(30*ang);
-	a1.dda_line(0,r,0-c,0-s);
-	a1.dda_line(0-c,0-s,0+c,0-s);
-	a1.dda_line(0+c,0-s,0,r);
-	r1=s;
-	a1.bresneham_cir((int)r1);
-	getch();
-	closegraph();
-	return 0;
-}
-// END OF CODE
\ No newline at end of file
diff --git a/Assignment A-3a (Pattern using DDA Line and Bresenham Circle Algorithm).cpp b/Assignment A-3a (Pattern using DDA Line and Bresenham Circle Algorithm).cpp
new file mode 100755
index 0000000..28efd20
--- /dev/null
+++ b/Assignment A-3a (Pattern using DDA Line and Bresenham Circle Algorithm).cpp	
@@ -0,0 +1,103 @@
+#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;
+}
\ No newline at end of file
diff --git a/Assignment A-3b (Pattern using DDA Line and Bresenham Circle Algorithm).cpp b/Assignment A-3b (Pattern using DDA Line and Bresenham Circle Algorithm).cpp
new file mode 100755
index 0000000..e89fc44
--- /dev/null
+++ b/Assignment A-3b (Pattern using DDA Line and Bresenham Circle Algorithm).cpp	
@@ -0,0 +1,111 @@
+#include <iostream>
+#include <graphics.h>
+#include <math.h>
+using namespace std;
+
+void bresenhamCircle(int xcord, int ycord, int rad) {
+// function to draw circle using Bresenhamn algorithm
+	int dec, x, y;
+	dec = 3-2*rad; // dec is decision parameter
+	x = 0;
+	y = rad;
+
+	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
+	float dx, dy, steps, x, y, xinc, yinc;
+
+	dx = abs(x2-x1);
+	dy = abs(y2-y1);
+
+	if (dx>dy) {
+		steps = dx;
+	}
+	else {
+		steps = dy;
+	}
+
+	x = x1;
+	y = y1;
+	putpixel(round(x), round(y), 15);
+
+	xinc = (x2-x1)/steps;
+	yinc = (y2-y1)/steps;
+	
+	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; // variables to store coordinates of rectangle
+	float X, Y; // variables to store coordinates of rhombus
+	int x, y, r; // variables to store coordinates of circle
+
+	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;
+	cout<<endl<<"Enter value for Y2:\t";
+	cin>>y2;
+
+	// initializing graphics window
+		int gd=DETECT, gm;
+		initgraph(&gd, &gm, NULL);
+
+	// making rectangle
+		ddaLine(x1, y1, x1, y2); // left line
+		ddaLine(x1, y2, x2, y2); // bottom line
+		ddaLine(x2, y2, x2, y1); // right line
+		ddaLine(x2, y1, x1, y1); // top line
+
+	// making rhombus
+		X=(x2+x1)/2;
+		Y=(y2+y1)/2;
+
+		ddaLine(X, y1, x2, Y); // top to right edge
+		ddaLine(x2, Y, X, y2); // right to bottom edge
+		ddaLine(X, y2, x1, Y); // bottom to left edge
+		ddaLine(x1, Y, X, y1); // left to top edge
+
+	// making circle inside rhombus
+	/*
+	NEVER REALLY FIGURED OUT HOW TO MAKE THIS ONE. IF YOU KNOW, PLEASE CONTRIBUTE.
+	*/
+		x = (x1+x2)/2;
+		y = (y1+y2)/2;
+		r = sqrt(pow((x2 - x1) / 4, 2) + pow((y2 - y1) / 4, 2));
+		bresenhamCircle(x,y,r);
+
+	delay(50000);
+	closegraph();
+	return 0;
+}
\ No newline at end of file
diff --git a/README.md b/README.md
index 3529452..2e99847 100644
--- a/README.md
+++ b/README.md
@@ -13,13 +13,14 @@ This repository contains codes, write-ups, lab manuals, lab notes and question p
 2. Assignment A-2 (Cohen Sutherland Line Clipping)
 	- [Using DDA](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20A-2%20%28Cohen%20Sutherland%20Line%20Clipping%29%20%28using%20DDA%29.cpp)
 	- [Using built-in functions](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20A-2%20%28Cohen%20Sutherland%20Line%20Clipping%29%20%28using%20built-in%20function%29.cpp)
-3. [Assignment A-3 (Pattern using DDA and Bresenham Line Drawing)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20A-3%20%28Pattern%20using%20DDA%20and%20Bresenham%20Line%20Drawing%29.cpp)
-4. [Assignment B-4 (Transformations)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-4%20%28Transformations%29.cpp)
-5. [Assignment B-5a (Snowflake)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-5a%20%28Snowflake%29.cpp)
-6. [Assignment B-5b (Hilbert Curve)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-5b%20%28Hilbert%20Curve%29.cpp)
-7. [Assignment B-5c (Koch Curve)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-5c%20%28Koch%20Curve%29.cpp)
-8. [Assignment C-6c (Sunrise and Sunset)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20C-6c%20%28Sunrise%20and%20Sunset%29.cpp)
-9. [Assignment C-7b (Bouncing Ball)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20C-7b%20%28Bouncing%20Ball%29.cpp)
+3. [Assignment A-3a (Pattern using DDA Line and Bresenham Circle Algorithm)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20A-3a%20%28Pattern%20using%20DDA%20Line%20and%20Bresenham%20Circle%20Algorithm%29.cpp) (Circle inside a triangle which is inside a bigger circle)
+4. [Assignment A-3b (Pattern using DDA Line and Bresenham Circle Algorithm)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20A-3b20%28Pattern%20using%20DDA%20Line%20and%20Bresenham%20Circle%20Algorithm%29.cpp) (Circle inside a rhombus which is inside a rectangle)
+5. [Assignment B-4 (Transformations)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-4%20%28Transformations%29.cpp)
+6. [Assignment B-5a (Snowflake)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-5a%20%28Snowflake%29.cpp)
+7. [Assignment B-5b (Hilbert Curve)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-5b%20%28Hilbert%20Curve%29.cpp)
+8. [Assignment B-5c (Koch Curve)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20B-5c%20%28Koch%20Curve%29.cpp)
+9. [Assignment C-6c (Sunrise and Sunset)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20C-6c%20%28Sunrise%20and%20Sunset%29.cpp)
+10. [Assignment C-7b (Bouncing Ball)](https://git.kska.io/sppu-se-comp-codes/CG/src/branch/main/Assignment%20C-7b%20%28Bouncing%20Ball%29.cpp)
 
 #### Digital Differential Analyzer (DDA):
 > Digital Differential Analyzer (DDA) is a line-drawing algorithm for digital displays, using incremental calculations to plot points between endpoints.
@@ -67,4 +68,4 @@ Maintained by:
 - [notkshitij](https://git.kska.io/notkshitij)
 - [TanmaySpamzzz](https://git.kska.io/TanmaySpamzzz)
 - [shh_itsourlittlesecret (Afan)](https://git.kska.io/shh_itsourlittlesecret)
-- [Kalaskar_admin03](https://git.kska.io/Kalaskar_admin03/)
\ No newline at end of file
+- [Kalaskar_admin03](https://git.kska.io/Kalaskar_admin03/)