circle.cpp

a source code for banker s algorithm

#include<windows.h>
#include<gl.h>
#include<glut.h>

int x,y,h,k;

void myInit(void)
{
  glClearColor(1.0,1.0,1.0,1.0);
  glColor3f(1.0f,0.0f,0.0f);
  glPointSize(2.0);
  gluOrtho2D(300.0,0.0,300.0,0.0);
}

void drawpixel(GLint m,GLint n)
{
  glColor3f(1.0,0.0,0.0);
  glBegin(GL_POINTS);
  glVertex2i(m,n);
   glEnd();
   glFlush();
}

void plotpixel(GLint h, GLint k, GLint x, GLint y)
{
   drawpixel(x+h,y+k);
   drawpixel(-x+h,y+k);
   drawpixel(x+h,-y+k);
   drawpixel(-x+h,-y+k);
   drawpixel(y+h,x+k);
   drawpixel(-y+h,x+k);
   drawpixel(y+h,-x+k);
   drawpixel(-y+h,-x+k);
   
}



void drawcircle(GLint h, GLint k, GLint r)
{
	GLint d=1-r,x=0,y=r;
  while(y>x)
  {
    plotpixel(h,k,x,y);
	if(d<0)
	{
		d+=2*x+3;
	}
	else
	{
		d+=2*(x-y)+5;
		--y;
	}
	++x;

  }
	plotpixel(h,k,x,y);
  
}


	void display(void)
	{
		int n;
		GLint xc=100,yc=100,r=49;
		glClear(GL_COLOR_BUFFER_BIT);
		for(n=0;n<=10;n++)
		{
		yc+=10;
		drawcircle(xc,yc,r);
		}
		glEnd();
		glFlush();
	}

	void main(void)
	{
		
		glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
		glutInitWindowSize(640,480);
		glutInitWindowPosition(100,50);
		glutCreateWindow("pixels");
		glutDisplayFunc(display);
		myInit();
		glutMainLoop();
	}