/*
Author: Azhar Khan
Rajasthan Technical University
Poornima Institute of Engineering And Technology
*/
#include <GL/glut.h>
#include <windows.h>
#include <stdio.h>
GLint x0,y0,xEnd,yEnd;
void init()
{
glClearColor(1.0,1.0,1.0,0.0);
glColor3f(1.0f,0.0f,0.0f);
glPointSize(1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0,600.0,0.0,600.0);
}
void setPixel(GLint xcoordinate, GLint ycoordinate)
{
glBegin(GL_POINTS);
glVertex2i(xcoordinate,ycoordinate);
glEnd();
glFlush();
}
void lineBA(GLint x0,GLint y0,GLint xEnd,GLint yEnd)
{
GLint dx = xEnd-x0;
GLint dy = yEnd-y0;
GLint steps,k;
steps=dx;
GLint x,y,p0=(2*dy)-dx;
setPixel(x0,y0);
x=x0;
y=y0;
for(k=0;k<steps;k++)
{
if(p0<0)
{
p0=p0+(2*dy);
x+=1;
}
else
{
p0=p0+(2*dy)-(2*dx);
x+=1;
y+=1;
}
setPixel(x,y);
}
}
void readInput()
{
printf("\nEnter x0, y0, xEnd, yEnd(resp): ");
scanf("%i %i %i %i",&x0,&y0,&xEnd,&yEnd);
}
void Display(void)
{
//static int i=1;
glClear(GL_COLOR_BUFFER_BIT);
lineBA(x0,y0,xEnd,yEnd);
}
int main(int argc,char** argv)
{
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutInitWindowSize(600,600);
glutInitWindowPosition(0,0);
glutCreateWindow("Breshnam's Line Drawing Algorithm");
readInput();
glutDisplayFunc(Display);
init();
glutMainLoop();
return 0;
}