cg/5.c at master · mohammedlutf/cg · GitHub

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#include <stdio.h>
#include <GL/glut.h>
#include <stdbool.h>

double xmin=50,ymin=50, xmax=100,ymax=100;
double xvmin=200,yvmin=200,xvmax=300,yvmax=300;

const int RIGHT = 8;
const int LEFT = 2;
const int TOP = 4;
const int BOTTOM = 1;

int x0, x1, y0, y1;

int ComputeOutCode (double x, double y);

void CohenSutherlandLineClipAndDraw (double x0, double y0,double x1, double y1)
{
int outcode0, outcode1, outcodeOut;
bool accept = false, done = false;
outcode0 = ComputeOutCode (x0, y0);
outcode1 = ComputeOutCode (x1, y1);

do
{
	if (!(outcode0 | outcode1))
	{
		accept = true;
		done = true;
	}
	else if (outcode0 & outcode1)
		done = true;
	else
	{
			double x, y;
			outcodeOut = outcode0 ? outcode0: outcode1;

			if (outcodeOut & TOP)
			{
				x = x0 + (x1 - x0) * (ymax - y0)/(y1 - y0);
				y = ymax;
			}
			else if (outcodeOut & BOTTOM)
			{
				x = x0 + (x1 - x0) * (ymin - y0)/(y1 - y0);
				y = ymin;
			}
			else if (outcodeOut & RIGHT)
			{
				y = y0 + (y1 - y0) * (xmax - x0)/(x1 - x0);
				x = xmax;
			}
			else
			{
				y = y0 + (y1 - y0) * (xmin - x0)/(x1 - x0);
				x = xmin;
			}


			if(outcodeOut == outcode0)
			{
				x0 = x;
				y0 = y;
				outcode0 = ComputeOutCode(x0, y0);
			}
			else
			{
				x1 = x;
				y1 = y;
				outcode1 = ComputeOutCode(x1, y1);
			}
		}

} while (!done);


if (accept)
{
	double sx=(xvmax-xvmin)/(xmax-xmin);
	double sy=(yvmax-yvmin)/(ymax-ymin);
	double vx0=xvmin+(x0-xmin)*sx;
	double vy0=yvmin+(y0-ymin)*sy;
	double vx1=xvmin+(x1-xmin)*sx;
	double vy1=yvmin+(y1-ymin)*sy;

	glColor3f(1.0, 0.0, 0.0);
	glBegin(GL_LINE_LOOP);
	glVertex2f(xvmin, yvmin);
	glVertex2f(xvmax, yvmin);
	glVertex2f(xvmax, yvmax);
	glVertex2f(xvmin, yvmax);
	glEnd();
	glColor3f(0.0,0.0,1.0);
	glBegin(GL_LINES);
	glVertex2d (vx0, vy0);
	glVertex2d (vx1, vy1);
	glEnd();
}
}


int ComputeOutCode (double x, double y)
{
	int code = 0;
	if (y > ymax)
	code |= TOP;
	else if (y < ymin)
	code |= BOTTOM;
	if (x > xmax)
	code |= RIGHT;
	else if (x < xmin)
	code |= LEFT;

	return code;
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1.0,0.0,0.0);
	glBegin(GL_LINES);
	glVertex2d (x0, y0);
	glVertex2d (x1, y1);
	glEnd();
	glColor3f(0.0, 0.0, 1.0);
	glBegin(GL_LINE_LOOP);
	glVertex2f(xmin, ymin);
	glVertex2f(xmax, ymin);
	glVertex2f(xmax, ymax);
	glVertex2f(xmin, ymax);
	glEnd();
	CohenSutherlandLineClipAndDraw(x0,y0,x1,y1);
	glFlush();
}

void myinit()
{
	glClearColor(1.0,1.0,1.0,1.0);
	glColor3f(1.0,0.0,0.0);
	glPointSize(1.0);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0,499.0,0.0,499.0);
}

void main(int argc, char** argv)
{

	printf("Enter End points:");
	scanf("%d%d%d%d", &x0,&y0,&x1,&y1);
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
	glutInitWindowSize(500,500);
	glutInitWindowPosition(0,0);
	glutCreateWindow("Cohen Suderland Line Clipping Algorithm");
	glutDisplayFunc(display);
	myinit();
	glutMainLoop();
}