// First Try: a first OpenGL graphics program

#include <windows.h>  // include windows header file
#include <Gl/glut.h>  // include OpenGL header file
#include <Gl/GL.H>
#include <Gl/GLAUX.H>
#include <Gl/GLU.H>

void myInit();  // function prototype for my initialization function
void myDisplay();  // function prototype for my display function

void main(int argc, char* argv[])  // main program function
{
    glutInit(&argc, argv);  // initialize the GLUT toolkit
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
    glutInitWindowSize(640, 480);  // set window size
    glutInitWindowPosition(50, 100);  // set window position on the screen
    glutCreateWindow("First Try");  // title and open the window

    glutDisplayFunc(myDisplay);  // register my display function

    myInit();  // call my initialization function
    glutMainLoop();  // begin endless main loop
}

void myInit()  // initialize Open GL state
{
    glClearColor(1.0, 1.0, 1.0, 0.0);  // set background color to white
    glColor3f(0.0, 0.0, 0.0);  // set drawing color to black
    glPointSize(4.0);  // set dot size to 4 pixels
    glMatrixMode(GL_PROJECTION);	
    glLoadIdentity();
    gluOrtho2D(0.0, 640.0, 0.0, 480.0);
}

void myDisplay()  // draw my image
{
    glClear(GL_COLOR_BUFFER_BIT);  // clear the screen
    glBegin(GL_POINTS);  // draw four points
        glVertex2i(150, 150);
        glVertex2i(200, 200);
        glVertex2i(150, 200);
        glVertex2i(200, 150);
    glEnd();
    glColor3f(0.0, 1.0, 0.0);  // set drawing color to green
    glBegin(GL_POLYGON);  // draw triangle
        glVertex2f(10.0, 10.0);
        glVertex2f(100.0, 10.0);
        glVertex2f(10.0, 100.0);
    glEnd();
    glFlush();  // send output to display
}