Bresenhams Line Drawing Algorithm in OpenGL C code

Bresenhams Line Drawing Algorithm in OpenGL C code

//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(" Enter 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("Breshnams Line Drawing Algorithm");
    readInput();
    glutDisplayFunc(Display);
    init();
    glutMainLoop();
    return 0;
}