/* Example 1.1.point.c: draw multiple randomly generated points */
// by Jim X. Chen; September 2000

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

#define Height 400
#define Width 400


void display(void)
{
	int x, y;

	//1. specify a drawing color: red
	glColor3f(1, 0, 0);
	
	//2. generate a random point
	x = rand() % Width; 
	y = rand() % Height; 

	//3. specify to draw the point
	glBegin(GL_POINTS);
		glVertex2i (x,y);
	glEnd();

	//4. make picture appear on the screen
	glFlush();	
}



static void reshape(int w, int h)
{
	//5. specify the window's coordinates
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();
    glOrtho(0, Width, 0, Height, -1.0, 1.0); 
}


int main(int argc, char **argv)
{
    //6. initialize a drawing area & window
	glutInit(&argc, argv);
 	glutInitDisplayMode(GLUT_SINGLE);
    glutInitWindowSize(Width, Height);
    glutCreateWindow("Example 1.1.point.c: randomly generated points");

	//7. event callback functions
    glutReshapeFunc(reshape); 
    glutDisplayFunc(display);
    glutIdleFunc(display);

    glutMainLoop();
}