Graphics/circle.cpp at master · sadeedameen/Graphics · GitHub

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/*
Circle Drawing algorithm
Sadeed Ameen PO
ROll No:267
*/
#include <GL/glut.h>
#include <iostream>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <wchar.h>

using namespace std;
void circlePlotPoints(int xCenter, int yCenter, int x, int y )
{
	glColor3f(0.0, 0.0, 0.0);
	glBegin(GL_POINTS);
		glVertex2i(xCenter + x, yCenter + y );
		glVertex2i(xCenter - x, yCenter + y );
		glVertex2i(xCenter + x, yCenter - y );
		glVertex2i(xCenter - x, yCenter - y );
		glVertex2i(xCenter + y, yCenter + x );
		glVertex2i(xCenter - y, yCenter + x );
		glVertex2i(xCenter + y, yCenter - x );
		glVertex2i(xCenter - y, yCenter - x );
	glEnd();
}

void drawCircle( int xCenter, int yCenter, int radius )
{

	int x = 0, y = radius, p = 1 - radius;
	circlePlotPoints( xCenter, yCenter, x, y );
	while( x < y )
	{
		x++;
		if( p < 0 )
		{
			p += (2 * x) + 1;
		}
		else
		{
			y--;
			p += ( 2*(x-y) ) +1;
		}
		circlePlotPoints(xCenter, yCenter, x, y);
	}

}

void mouseClick( int button, int state, int x, int y )
{
	if( button == GLUT_LEFT_BUTTON )
	{
		if( state == GLUT_DOWN )
		{

			drawCircle(x, 500-y, 20);
			glutSwapBuffers();
		}
	}
}

void display()
{
	glClearColor(1.0, 1.0, 1.0, 0.0);
	glClear(GL_COLOR_BUFFER_BIT);
	glutSwapBuffers();
}
int main(int argc, char **argv)
{

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowPosition(50,50);
	glutInitWindowSize(800, 500);
	glutCreateWindow("Midpoint Circle Generation");
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, 800, 0, 500);
	glutDisplayFunc(display);
	glutMouseFunc(mouseClick);
	glutMainLoop();

	return 0;
}
//End Of program