OPenGl -Bresenhams

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

void draw(int x ,int y){
	glBegin(GL_POINTS);
	glColor3f(0,1,0);
	glVertex2i(x,y);
	glEnd();
	}

void lineSe(){
	float x0 = 0,y0= 0;
	float xf= 500,yf=500;
	int step = (abs(x0-xf)>abs(y0-yf)?abs(x0-xf):abs(y0-yf) );
	int p=-1;
	int dx = abs(x0-xf);
	int dy = abs(y0-yf);
	if(dx>dy){
	p=2*dy-dx;
	while(x0 != xf && y0 != yf){
 		draw(x0,y0);
		if(p<0){
			x0+=1;
			p+=2*dy;
			}
		else {
			x0+=1;
			y0+=1;
			p+=2*dy-2*dx;
			}
		}
	}else{
	p=2*dx-dy;
	while(x0 != xf && y0 != yf){
 		draw(x0,y0);
		if(p<0){
			y0+=1;
			p+=2*dx;
			}
		else {
			x0+=1;
			y0+=1;
			p+=2*dx-2*dy;
			}
		}
	}
			
	glFlush();
	}

void Init(){
	glClearColor(1.0,1.0,1.0,0.0);
	glClear(GL_COLOR_BUFFER_BIT);
	gluOrtho2D(-640,640,-480,480);
	lineSe();
}

int main(int argc ,char ** argv){
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE );
	glutInitWindowPosition(100,100);
	glutInitWindowSize(800,800);
	glutCreateWindow("BRESENHAM Line");
	Init();
	glutDisplayFunc(lineSe);
	glutMainLoop();
	return 0;
	}