/* The only code you need to modify here is in the
   methods Line, and makeList
*/

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
import com.sun.opengl.util.*;
import java.nio.*;

public class HW1 implements GLEventListener, 
                                  MouseListener, 
                                  MouseMotionListener,
                                  KeyListener {
                                 
   static class ProgramTerminator implements WindowListener
        {
           public void windowClosing(WindowEvent event)
             {
                System.exit(0);
             }
     
           public void windowActivated(WindowEvent event) {}
           public void windowClosed(WindowEvent event) {}
           public void windowDeactivated(WindowEvent event) {}
           public void windowDeiconified(WindowEvent event) {}
           public void windowIconified(WindowEvent event) {}
           public void windowOpened(WindowEvent event) {}
        }

   private GLAutoDrawable draw;    
   public static int xres,yres;
   public static String lineFileName;

   public static void main(String[] args) {

      Frame frame = new Frame("HW1");
      xres = 801;
      yres = 801;
      lineFileName = args[0];
      frame.setSize(xres,yres);
      frame.addWindowListener(new ProgramTerminator());
      GLCanvas canvas = new GLCanvas();
      canvas.addGLEventListener(new HW1());

      frame.add(canvas);
      frame.setVisible(true);
     }

// Methods required for implementation of GLEventListener

   public void init(GLAutoDrawable drawable) {
    draw = drawable;  // save this for use by other methods
    GL gl = drawable.getGL();
    GLU glu = new GLU();
    gl.glMatrixMode(GL.GL_PROJECTION);
    gl.glLoadIdentity();
    glu.gluOrtho2D((double) -xres/2,(double) xres/2,(double) -yres/2,(double) yres/2);
    gl.glTranslatef(0.375f, 0.375f, 0.0f);
    gl.glMatrixMode(GL.GL_MODELVIEW);
    makeList(lineFileName);

    drawable.addMouseListener(this);
    drawable.addMouseMotionListener(this);
    drawable.addKeyListener(this);
   }

   public void display(GLAutoDrawable drawable) {
       GL gl = drawable.getGL();
       gl.glClearColor(1.0f,1.0f,1.0f,0.0f);
       gl.glClear(GL.GL_COLOR_BUFFER_BIT);  // Clear window
       gl.glCallList(1); // There may be more than one List
    }

   public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {}
   public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {}


// Methods required for the implementation of MouseListener

  private int prevMouseX, prevMouseY;
  private boolean mouseRButtonDown = false;

  public void mouseEntered(MouseEvent e) {}  // not implemented
  public void mouseExited(MouseEvent e) {}   // not implemented

  public void mousePressed(MouseEvent e) {
    int x  = e.getX();
    int y  = e.getY();
    if ((e.getModifiers() & e.BUTTON3_MASK) != 0) {
      mouseRButtonDown = true;
    }
  }

  public void mouseReleased(MouseEvent e) {
    if ((e.getModifiers() & e.BUTTON3_MASK) != 0) {
      mouseRButtonDown = false;
    }
  }

  public void mouseClicked(MouseEvent e) {
    int x  = e.getX();
    int y = e.getY();
   }

  // Methods required for the implementation of MouseMotionListener

  public void mouseDragged(MouseEvent e) {
   }

  public void mouseMoved(MouseEvent e) {}
   
  // Methods required for the implementation of KeyListener

  public void keyPressed(KeyEvent e) {}
  public void keyReleased(KeyEvent e) {}
  public void keyTyped(KeyEvent e) {
     char c = e.getKeyChar();
 
     switch (c) {
        case 'q': System.exit(0);
                  break;
      }  
   }

//  OpenGL graphics

   public void line(GL gl,int x1, int y1,int x2,int y2,float color[])
    {
       // Implement Bresenham's algorithm here
       // modified so that it works for all slopes
       // and both positive and negative dx and dy.
       // When a pixel (x,y) is found on the line
       // call setPixel(x,y,color)

      // Test code that you will remove:
         for (int i=x1;i<x2;i++)
              setPixel(gl,i,y1,color);
    }

   public void makeList(String fName)
     {
	Scanner lineFile = null;
        try {
	    lineFile = new Scanner(new FileInputStream(fName));
	}
	catch(FileNotFoundException e) {
	    System.out.println( "Can't find the file " + fName + "." );
	    System.exit(1);
	}
        int x1,x2,y1,y2;

        GL gl = draw.getGL();
        float color[] = {0.0f,0.0f,0.0f};
        gl.glDeleteLists(1, 1);
        gl.glNewList(1,GL.GL_COMPILE);
           while (lineFile.hasNextInt())
             {
                x1 = lineFile.nextInt(); 
                y1 = lineFile.nextInt(); 
                x2 = lineFile.nextInt(); 
                y2 = lineFile.nextInt(); 
                line(gl,x1,y1,x2,y2,color);
                gl.glFlush();
             }
        gl.glEndList();
     }

// This method implemented because in Java, glDrawPixels can't accept
//   arrays of floats but requires a FloatBuffer

   private FloatBuffer arrayToBuffer(float [] x)
     {
      int n = x.length;
      FloatBuffer col = FloatBuffer.allocate(n);
      for (int i=0;i<n;i++) col.put(i,x[i]);
      return col;
     }

   public void setPixel(GL gl,int x, int y, float [] col)
    {
      gl.glRasterPos2i(x,y);
      gl.glDrawPixels(1,1,GL.GL_RGB,GL.GL_FLOAT, arrayToBuffer(col));
    }
}