//--------------------------------------------------
// GLWidget.cpp -- implementation of GLWidget class
//--------------------------------------------------

import javax.media.opengl.*;
import javax.media.opengl.glu.GLU;
import java.awt.event.*;
import java.lang.String;
import java.lang.*;

			// the main class that facilitates OpenGL rendering
			// the listeners are combined to consolidate all interaction
			// but must add each listener separately to the canvas
			// --- done in mainWindow
public class glWidget implements GLEventListener, MouseListener, 
						MouseMotionListener
{
	int x0, x1, y0, y1;
	int num_points;
	static mainWindow gui;
	GLJPanel canvas;

	private static final GLU glu = new GLU();

	glWidget(mainWindow mainwin, GLJPanel cnvs)
	{
		gui = mainwin;
		canvas = cnvs;
		num_points = 0;
	}
								// all GL rendering is generally done
								// in the display function.
	public void display(GLAutoDrawable gLDrawable)
	{
								// get the gl context
		final GL gl = gLDrawable.getGL();
		if (gui.getCurrentMode() == "Draw Line")
		{
								// two succeeding mouse clicks draws a line
								// controlled from mousePressed()
			if (num_points == 2) 
			{
						// Draw a "tan" line from (x0,y0) to (x1,y1)
				gl.glBegin(gl.GL_LINES);
          			gl.glColor3f( 1.0f, 0.5f, 0.0f );
					gl.glVertex2i( x0, y0 );
					gl.glVertex2i( x1, y1 );
				gl.glEnd();
				num_points = 0;
			}
		}
								// initial mouse click + dragging draws
								// a continuous line
		else if (gui.getCurrentMode() == "Draw Freehand")
		{		
			gl.glBegin(gl.GL_LINES);
          		gl.glColor3f( 0.0f, 1.0f, 0.5f );
				gl.glVertex2i( x0, y0 );
				gl.glVertex2i( x1, y1 );
			gl.glEnd();
		}
		else if (gui.getCurrentMode() == "Clear Canvas")
		{
			gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
			gl.glClear(gl.GL_COLOR_BUFFER_BIT);
		}
	}

	public void displayChanged(GLAutoDrawable gLDrawable,
			boolean modeChanged, boolean deviceChanged) 
	{
    }
	public void init(GLAutoDrawable gLDrawable) 
	{
		final GL gl = gLDrawable.getGL();
		gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
		gl.glClear(gl.GL_COLOR_BUFFER_BIT);
 		glu.gluOrtho2D(0, 640, 437, 0);
		display(gLDrawable);
	}

								// when window is resized, gl is notified
								// through this function
	public void reshape(GLAutoDrawable gLDrawable, int x,
					int y, int width, int height)
	{
		if (height <= 0) 
			height = 1;

		final GL gl = gLDrawable.getGL();
		gl.glMatrixMode(GL.GL_PROJECTION);
		gl.glLoadIdentity();
		glu.gluOrtho2D(0, width, height, 0);
		gl.glMatrixMode(GL.GL_MODELVIEW);
		gl.glLoadIdentity();
		display(gLDrawable);
	}
	public void changeMode (String m)
	{
						// do some initializations
		x0 = x1 = y0 = y1 = 0;
		num_points = 0;
	}
						// Mouse callbacks
	public void mousePressed(MouseEvent e)
	{
		if (gui.getCurrentMode() == "Draw Line") 
		{
			if (num_points == 0)
			{
				x0 = e.getX();
				y0 = e.getY();
				num_points++;
			}
			else if (num_points == 1)
        	{
					// Get the second point and draw line
          		x1 = e.getX();
				y1 = e.getY();
				num_points++;
				canvas.display();

			}
		}
		else if (gui.getCurrentMode() == "Draw Freehand") 
		{
			x0 = x1 = e.getX();
			y0 = y1 = e.getY();
		}
	}
	public void mouseDragged(MouseEvent e)
	{
		if (gui.getCurrentMode() == "Draw Freehand") 
		{
			x1 = e.getX();
			y1 = e.getY();

			canvas.display();

			x0 = x1;
			y0 = y1;
		}
	}
	public void mouseMoved(MouseEvent e)
	{
	}
	public void mouseReleased(MouseEvent e)
	{
	}
	public void mouseEntered(MouseEvent e)
	{
	}
	public void mouseExited(MouseEvent e)
	{
	}
	public void mouseClicked(MouseEvent e)
	{
	}
};