import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.awt.image.ColorModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;


public class BRDFView extends JApplet implements  Runnable, MouseListener, ComponentListener, ChangeListener {
    
    Random generator = new Random();
    BufferedImage offScreenImage;
    int width, height;
    int i = 0;
    Thread t = null;
    boolean threadSuspended;
    Font waterFont = new Font("Georgia", Font.PLAIN,20);
    
    boolean mousePressed = false;
    
    int length = 175;
    double angle;
    
    JPanel canvas = new JPanel();
    JPanel controls = new JPanel();
    sgSlider angleSlider = new sgSlider("Angle:",180,270,235);
    sgSlider glossSlider = new sgSlider("Shiny:",3,1000,10);
    
    boolean valid = false;

    int mouseX = -10;
    
    
    public void init() {
        
        addMouseListener(this);
        addComponentListener(this);

        angleSlider.slider.addChangeListener(this);
        glossSlider.slider.addChangeListener(this);
        controls.add(angleSlider,"West");
        controls.add(glossSlider,"East");
        add(canvas,"Center");
        add(controls,"South");
        
    }
    
    
    public void start() {
        if ( t == null ) {
            t = new Thread( this );
            threadSuspended = false;
            t.start();
            
        } else {
            if ( threadSuspended ) {
                threadSuspended = false;
                
                synchronized( this ) {
                    notify();
                }
            }
        }
    }
    
    public void stop() {
        threadSuspended = true;
    }
    
    // Executed within the thread that this applet created.
    public void run() {
        try {
            while (true) {
                
                // Now the thread checks to see if it should suspend itself
                if ( threadSuspended ) {
                    synchronized( this ) {
                        while ( threadSuspended ) {
                            wait();
                        }
                    }
                }
                
                update(canvas.getGraphics());
                t.sleep( 1000/10 );  // interval given in milliseconds
            }
        } catch (InterruptedException e) { }
    }
    
    public void paint( Graphics g ) {
        
        width = canvas.getSize().width;
        height = canvas.getSize().height;
        
        angle = (angleSlider.getValue()-90)*Math.PI/180;
        
      
        Graphics2D g2d = (Graphics2D)g;
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  
 
        g2d.setFont(waterFont);

        
        g2d.setStroke(new BasicStroke(1.5f));
        g2d.setColor(Color.white);
        g2d.fillRect(0,0,width,height);
  
        
        g2d.translate(0,70); 
        
        g2d.setColor(Color.black);
        
        g2d.drawLine(0,height/2,width,height/2);
 
        g2d.setColor(Color.blue);
        g2d.drawLine(width/2,height/2, (int)(width/2 - length*Math.cos(angle)), (int)(height/2-length*Math.sin(angle)));
  
        g2d.setColor(Color.green);
        g2d.drawLine(width/2,height/2, width/2,height/2-length);       
        
        Path2D.Double brdf  = new Path2D.Double(); 
        brdf.moveTo(width/2,height/2);
        
        g2d.setColor(Color.gray);
        g2d.drawLine(175, height/2, 175, height/2-150);

        
        double val = 0, k,ai,ar;
        int gloss = glossSlider.getValue();

        g2d.setColor(Color.black);
        if (gloss < 900) g2d.drawString("Phong",10,-50);
        else g2d.drawString("Mirror",10,-50);
        for (double i = 0; i < 120*Math.PI/180; i+=.05){
            
            //generate reflected vector
            ai = angle - Math.PI/2;
            ar = Math.PI/2 - ai;
            
           
            g2d.setColor(Color.red);
            if (i == 0) g2d.drawLine(width/2,height/2, (int)(width/2 - 1.1*length*Math.cos(ar)), (int)(height/2-1.1*length*Math.sin(ar)));
           
            
            k = i - ar;
            val = length*Math.pow(Math.cos(k),gloss);
            
            if (gloss < 900) brdf.lineTo(width/2 - val*Math.cos(i), height/2 - val*Math.sin(i));
            
        }
        brdf.lineTo(width/2,height/2);

        g2d.setPaint(new Color(.0f,.0f,.2f,.25f));

        g2d.fill(brdf);
        
        g2d.setColor(Color.black);

        g2d.draw(brdf);
        
        controls.invalidate();
        controls.repaint();
        
    }
    static public void main(String [] argv){
        
        
        
        BRDFView smonkaroni = new BRDFView();
        JFrame frame = new JFrame("Blarg!");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(smonkaroni);
        frame.setSize(550,300);
        frame.setVisible(true);
        
        smonkaroni.init();
        smonkaroni.start();
        
        //yes, call it again. It's a hack
        frame.setSize(550,300);
        frame.setVisible(true);
        
        
    }
    
    public void mousePressed(MouseEvent e) {
        mousePressed = true;

    }
    
    public void mouseReleased(MouseEvent e) {
        mousePressed = false;
    }
    
    public void mouseEntered(MouseEvent e) {
        
    }
    
    public void mouseExited(MouseEvent e) {
        
    }
    
    public void mouseClicked(MouseEvent e) {
        
    }
    
    
//perform double buffering manually
    public void update( Graphics g ){
        
        if ( offScreenImage == null){
            Image img = createImage( getSize().width, getSize().height );
            Image img2 = createImage( getSize().width, getSize().height );
            offScreenImage = (BufferedImage)img;

        }
        Graphics gOffScreenImage = offScreenImage.getGraphics();
        
        //Now draw on the offscreen image.
        if (!valid) paint( gOffScreenImage );
        g.drawImage(offScreenImage, 0, 0, this);
        gOffScreenImage.dispose();
    }
    
    public void componentResized(ComponentEvent e) {
        offScreenImage = null;
    }
    
    public void componentMoved(ComponentEvent e) {
    }
    
    public void componentShown(ComponentEvent e) {
    }
    
    public void componentHidden(ComponentEvent e) {
    }
    
    public void stateChanged(ChangeEvent e) {
        valid = false;

    }
    
    
    
}



class sgSlider extends JPanel{
    
    JLabel label;
    JSlider slider;
    int min,max;
    JPanel area;
    
    public sgSlider(String label, int min, int max, int value){
        this.label = new JLabel(label);
        slider = new JSlider(min,max,value);
        
        add(this.label);
        add(slider);
    }
    
    public int getValue(){
        return slider.getValue();
    }
    
}

class sgText extends JPanel{
    
    JLabel label;
    JTextField text;
    JPanel area;
    
    public sgText(String label, String value){
        this.label = new JLabel(label);
        text = new JTextField(value,15);
        
        add(this.label);
        add(text);
    }
    
    public String getText(){
        return text.getText();
    }
    
}

class sgCheck extends JPanel{
    
    JLabel label;
    JCheckBox check;
    JPanel area;
    
    public sgCheck(String label, boolean checked){
        this.label = new JLabel(label);
        check = new JCheckBox();
        check.setSelected(checked);
        
        add(this.label);
        add(check);
    }
    
    public boolean isChecked(){
        return check.isSelected();
    }
    
}