Logo 
Search:

C++ Programming Articles

Submit Article
Home » Articles » C++ Programming » Computer GraphicsRSS Feeds

Program of Sutherland Hodgemann Algorithm for Polygon clipping

Posted By: Easy Tutor     Category: C++ Programming     Views: 17188

Write a program of sutherland hodgemann algorithm for polygon clipping.

Code for Program of Sutherland Hodgemann Algorithm for Polygon clipping in C++ Programming

#include<stdio.h>
#include<conio.h>
#include<iostream.h>
#include<graphics.h>
#define ROUND(a) ((int)(a+0.5))
#define n 4

#define LEFT_EDGE 0x1
#define RIGHT_EDGE 0x2
#define BOTTOM_EDGE 0x4
#define TOP_EDGE 0x8

#define INSIDE(a)  (!a)
#define REJECT(a,b) (a&b)
#define ACCEPT(a,b) (!(a|b))

typedef struct wcpt2
{
    int x,y;
}wcpt2;

typedef struct dcpt
{
    int x,y;
}dcpt;

void main()
{
    int gd=DETECT,gm;
    int left,top,right,bottom;
    int x1,x2,y1,y2;
    int maxx, maxy;
       /* our polygon array */int poly[10];
    void clipline(dcpt,dcpt,wcpt2,wcpt2);
    clrscr();

    initgraph(&gd,&gm,"c:\\tc30\\bgi");
    maxx = getmaxx()/4;
    maxy = getmaxy()/4;

    poly[0] = 20;        /* 1st vertex */
    poly[1] = maxy / 2;

    poly[2] = maxx - 10; /* 2nd */
    poly[3] = 10;

    poly[4] = maxx - 50; /* 3rd */
    poly[5] = maxy - 20;

    poly[6] = maxx / 2;  /* 4th */
    poly[7] = maxy / 2;

/*   drawpoly doesn't automatically close   the polygon, so we close it.*/
    poly[8] = poly[0];
    poly[9] = poly[1];

   /* draw the polygon */
    drawpoly(5, poly);

    rectangle(20,25,80,125);
    wcpt2 pt1,pt2;
    dcpt winmin,winmax;

    winmin.x=20;
    winmin.y=25;
    winmax.x=80;
    winmax.y=125;

    pt1.x=20;
    pt1.y=maxy/2;
    pt2.x=maxx-10;
    pt2.y=10;

//    clipline(winmin,winmax,pt1,pt2);int i=0;
    for(int index=0;index<n;index++)
    {
        if(index==n-1)
        {
            pt1.x=poly[i];
            pt1.y=poly[i+1];
            i=0;
            pt2.x=poly[i];
            pt2.y=poly[i+1];
            clipline(winmin,winmax,pt1,pt2);
        }
        else
        {
            pt1.x=poly[i];
            pt1.y=poly[i+1];
            pt2.x=poly[i+2];
            pt2.y=poly[i+3];
            clipline(winmin,winmax,pt1,pt2);
        }
        i+=2;
    }
    pt1.x=poly[i];
    pt1.y=poly[i+1];
    clipline(winmin,winmax,pt1,pt2);
    getch();
}


unsigned char encode(wcpt2 pt,dcpt winmin,dcpt winmax)
{
    unsigned char code=0x00;
    if(pt.x < winmin.x)
        code=code | LEFT_EDGE;
    if(pt.x > winmax.x)
        code=code | RIGHT_EDGE;
    if(pt.y < winmin.y)
        code=code | TOP_EDGE;
    if(pt.y > winmax.y)
        code=code | BOTTOM_EDGE;
    return code;
}


void swappts(wcpt2 *p1,wcpt2 *p2)
{
    wcpt2 tmp;
    tmp = *p1;
    *p1 = *p2;
    *p2 = tmp;
}


void swapcode(unsigned char *c1,unsigned char *c2)
{
    unsigned char tmp;
    tmp = *c1;
    *c1 = *c2;
    *c2 = tmp;
}


void clipline(dcpt winmin,dcpt winmax,wcpt2 p1,wcpt2 p2)
{
    unsigned char encode(wcpt2,dcpt,dcpt);
    unsigned char code1,code2;
    int done = 0 , draw = 0;
    float m;
    void swapcode(unsigned char *c1,unsigned char *c2);
    void swappts(wcpt2 *p1,wcpt2 *p2);

    while(!done)
    {
        code1 = encode(p1,winmin,winmax);
        code2 = encode(p2,winmin,winmax);
        if(ACCEPT(code1,code2))
        {
            draw = 1;
            done = 1;
        }
        elseif(REJECT(code1,code2))
            done = 1;
        elseif(INSIDE(code1))
        {
                swappts(&p1,&p2);
                swapcode(&code1,&code2);
        }
        if(code1 & LEFT_EDGE)
        {
                p1.y += (winmin.x - p1.x) *  (p2.y - p1.y) / (p2.x - p1.x);
                p1.x = winmin.x;
        }
        elseif(code1 & RIGHT_EDGE)
        {
                p1.y += (winmax.x - p1.x) *  (p2.y - p1.y) / (p2.x - p1.x);
                p1.x = winmax.x;
        }
        elseif(code1 & TOP_EDGE)
        {
            if(p2.x != p1.x)
                p1.x += (winmin.y - p1.y) *  (p2.x - p1.x) / (p2.y - p1.y);
                p1.y = winmin.y;
        }
        elseif(code1 & BOTTOM_EDGE)
        {
            if(p2.x != p1.x)
                p1.x += (winmax.y - p1.y) *  (p2.x - p1.x) / (p2.y - p1.y);
                p1.y = winmax.y;
        }
    }
    if(draw)
    {
    setcolor(5);
    line(p1.x,p1.y,p2.x,p2.y);
    }
}
  
Share: 



Easy Tutor
Easy Tutor author of Program of Sutherland Hodgemann Algorithm for Polygon clipping is from United States. Easy Tutor says

Hello Friends,

I am Free Lance Tutor, who helped student in completing their homework.

I have 4 Years of hands on experience on helping student in completing their homework. I also guide them in doing their final year projects.

I have share many programs on this website for everyone to use freely, if you need further assistance, than please contact me on easytutor.2ya [at the rate] gmail [dot] com

I have special discount scheme for providing tutor services. I am providing tutor service to students from various contries, currently most of my students are from United States, India, Australia, Pakistan, Germany, UK and Canada.

I am also here to expand my technical network to receive more opportunity in my career, make friends to help them in resolving their technical problem, learn and share my knowledge, If you like to be my friend, Please send me friend request.

Thanks,
Happy Programming :)

 
View All Articles

 
Please enter your Comment

  • Comment should be atleast 30 Characters.
  • Please put code inside [Code] your code [/Code].

 
No Comment Found, Be the First to post comment!