#include <GL/gl.h>
#include <GL/glut.h>
#include <stdlib.h>


int   x1, x2, y1, y2, dx, dy;
float ix, iy,step;


void display(void)
{


glClear (GL_COLOR_BUFFER_BIT);
glColor3f (1.0, 1.0, 1.0);


dx = abs(x2-x1);
dy = abs(y2-y1);


if(abs(dx) > abs(dy) ){
        step = abs(dx);
    }
    else
    {
        step = abs(dy);
    }

    ix = dx/step;
    iy = dy/step;

    float x=x1, y=y1;

    glBegin(GL_POINTS);
    glVertex2i (abs(x), abs(y));

    //glEnd(); Can't use glEnd Here otherwise it will not display the next looping poinr



    int i;
    for (i = 0; i<step; i++)
    {
        x = x + ix;
        y = y + iy;

        printf("%.1f %.1f %.1f %.1f %.1f", x, y, step, ix, iy);
        printf("\n");

        glVertex2i (abs(x), abs(y));
        // then again here you can't use glEnd() here otherwise it will stop drawing after one loop
    }

glEnd();

glutSwapBuffers();
}
void init (void)
{

glClearColor (0.0, 0.0, 0.0, 0.0);   /* select clearing (background) color */
glMatrixMode(GL_PROJECTION);        /* initialize viewing values */
glLoadIdentity();
glOrtho(0.0, 200.0, 0.0, 200.0, -200.0, 200.0);

}


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


    printf("Please Enter X1 Value: ");
    scanf("%d", &x1);
    printf("Please Enter Y1 Value: ");
    scanf("%d", &y1);
    printf("Please Enter X2 Value: ");
    scanf("%d", &x2);
    printf("Please Enter Y2 Value: ");
    scanf("%d", &y2);






glutInit(&argc, argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize (300, 300);
glutInitWindowPosition (100, 100);
glutCreateWindow ("hello");
init ();
glutDisplayFunc(display);
glutMainLoop();
return 0; /* ISO C requires main to return int. */
}