/** 
 * This is based on page 66 of Hill 2nd edition.  It shows how we can get mouse and
 * keyboard input.
 */ 

import java.awt.*;
import java.util.*;
import java.awt.event.*;
import javax.media.opengl.*;
import javax.media.opengl.glu.*;

public class polyLineDraw extends Frame implements GLEventListener, MouseListener, KeyListener {
    

    int width = 640;   //window width and height
    int height = 480;
    ArrayList<Point> polyline = new ArrayList<Point>();  // the polyline we are creating
    GLCanvas canvas;  //the GLCanvas we use for drawing
    public polyLineDraw() {
	
	canvas = new GLCanvas();
	
	canvas.addGLEventListener(this);
	canvas.addMouseListener( this ); 
	canvas.addKeyListener( this ); 

	add("Center", canvas);
	setSize(width,height);
	setVisible(true);
    }
    
    
    public static void main( String args[]) {
    
    
	polyLineDraw frame = new polyLineDraw();
	
	//exit if frame's close box is clicked
	frame.addWindowListener( new WindowAdapter() {
		public void windowClosed(WindowEvent e){
		    System.exit(0);
		}
		public void windowClosing(WindowEvent e) {
		    windowClosed(e);
		}
	    }
				 );
	
    }

    /* The functions below are required because we are a GLEventListener.
       We could also have put them in another class and put that class in the
       addGLEventListener method above.
    */

    //drawing colour
    double red,green,blue;

    /** 
     * Executed exactly once to initialize the 
     * associated GLDrawable
     */ 

    public void init(GLAutoDrawable drawable) {
	GL gl = drawable.getGL();
	/** 
	 * Set the background colour when the GLDrawable 
	 * is cleared 
	 */ 
	gl.glClearColor( 1.0f, 1.0f, 1.0f, 1.0f ); //white
    }
    
    
    /** 
     * Executed if the associated GLDrawable is resized
     */ 
    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
	GL gl = drawable.getGL();
	this.width = width;
        this.height = height;

	gl.glViewport( x, y, width, height );

	gl.glMatrixMode( GL.GL_PROJECTION ); 
	gl.glLoadIdentity();
	gl.glOrtho( x, width , y, height, -1 ,1);
    }

    /** This method handles the painting of the GLDrawable */
    
    public void display(GLAutoDrawable drawable) {
	GL gl = drawable.getGL();
	/** Clear the colour buffer */
	gl.glClear( GL.GL_COLOR_BUFFER_BIT );
        gl.glColor3d(red, green, blue);
	gl.glBegin( GL.GL_LINE_STRIP );  //draw the polyline 
	for(int i = 0; i < polyline.size(); i++) {
	    Point p = polyline.get(i);
	    gl.glVertex2i(p.x, p.y);
	}
	gl.glEnd(); 
    }

    /** This method handles things if display depth changes */
    public void displayChanged(GLAutoDrawable drawable,
			       boolean modeChanged,
			       boolean deviceChanged){
    }

    //need these methods because we are a mouse listener
    public void mouseClicked(MouseEvent e) {
	if (e.isMetaDown()) { //right click
	    //start new polyline
	    polyline = new ArrayList<Point>();
	} else  {
	    Point p = new Point (e.getX(),
				 height - e.getY());
	    // AWT has y axis going up, GL, down
	    polyline.add(p);
	}
	canvas.repaint();
    }

    public void mouseEntered(MouseEvent e) {
    }

    public void mousePressed(MouseEvent e) {
    }

    public void mouseReleased(MouseEvent e) {
    }

    public void mouseExited(MouseEvent e) {
    }
    /** Handles keyboard events */
    public void keyPressed( KeyEvent evt ) { 
	/** 
	 * Check if we've pressed 'c' or 'C'. If so, change 
	 * the colour! 
	 */
	if ( evt.getKeyChar() == 'q' || evt.getKeyChar() == 'Q' ) {
	    System.exit(0);
	}

	if ( evt.getKeyChar() == 'c' || evt.getKeyChar() == 'C' ) { 
	    red = Math.random();
	    green = Math.random();
	    blue = Math.random();
	    
	    canvas.repaint();
	}
	return;
    }

    public void keyTyped( KeyEvent evt ) { }
    public void keyReleased( KeyEvent evt ) { }

}