CohenSutherLand1.cpp

#include<graphics.h>
#include<conio.h>
#include<iostream.h>
#define xmin 150
#define xmax 500
#define ymin 100
#define ymax 370
enum {ABOVE = 0x8,BELOW = 0x4,RIGHT = 0x2,LEFT = 0x1};
unsigned int encode(int x,int y)
{
unsigned int c=0x0;
enum
{
ABOVE = 0x8,BELOW = 0x4,RIGHT = 0x2,LEFT = 0x1
};
if(x<xmin)
	c=c|LEFT;
	if(x>xmax)
		c=c|RIGHT;
		if(y<ymin)
			c=c|BELOW;
			if(y>ymax)
				c=c|ABOVE;
return c; 
}
// accept=0 line discarder done=0 further calculation requred if 1 no further calculaion required
void check(unsigned int code1,unsigned int code2,int x1,int y1,int x2,int y2){
int accept=0,done=0;
do{
if(!(code1|code2)) // If both 0000
{
accept=1;done=1; // line added and no further calculation
}
else if(code1&code2)  //bit wise and operation if pv
{
accept=0;done=1; //line discarder further calculation
}
else
{
float m =(y2-y1)/float (x2-x1),x,y;
int code=code1?code1:code2;
if(code & ABOVE) //above
{
y=ymax;
x=x1+(y-y1)/m;
}
else if(code & BELOW) //below
{
y=ymin;
x=x1+(y-y1)/m;
}
else if(code & LEFT) //left
{
x=xmin;
y=m*(x-x1)+y1;
}
else   //right
{
x=xmax;
y=m*(x-x1)+y1;
}
//compare the code if equal new value assigned
if(code==code1){
x1=x;y1=y;
code1=encode(x1,y1);
}
else
{
x2=x;y2=y;
code2=encode(x2,y2);
}
}
}
while(!done);
if(accept)
{cout<<"Accepted"<<endl;
line(x1,y1,x2,y2);
}
}
void bin(unsigned int c){
for(int i=8;i>0;i/=2)
(c&i)?cout<<"1":cout<<"0";
cout<<endl;
}
void main(){
int gd=DETECT,gm;
clrscr();
initgraph(&gd,&gm,"");
int x1,x2,y1,y2;
unsigned int code1,code2;
cout<<"Enter Coordinates"<<endl;
cout<<"X1,Y1: ";
cin>>x1>>y1;
cout<<"X2,Y2: ";
cin>>x2>>y2;
code1=encode(x1,y1);
code2=encode(x2,y2);
line(xmin,0,xmin,getmaxy());
line(xmax,0,xmax,getmaxy());
line(0,ymin,getmaxx(),ymin);
line(0,ymax,getmaxx(),ymax);
cout<<"Region Code Point 1: ";
bin(code1);
cout<<"Region Code Point 2: ";
bin(code2);
check(code1,code2,x1,y1,x2,y2);
getch();
closegraph();
}