/*
 * Portions Copyright (C) 2003 Sun Microsystems, Inc.
 * All rights reserved.
 */

/*
 *
 * COPYRIGHT NVIDIA CORPORATION 2003. ALL RIGHTS RESERVED.
 * BY ACCESSING OR USING THIS SOFTWARE, YOU AGREE TO:
 *
 *  1) ACKNOWLEDGE NVIDIA'S EXCLUSIVE OWNERSHIP OF ALL RIGHTS
 *     IN AND TO THE SOFTWARE;
 *
 *  2) NOT MAKE OR DISTRIBUTE COPIES OF THE SOFTWARE WITHOUT
 *     INCLUDING THIS NOTICE AND AGREEMENT;
 *
 *  3) ACKNOWLEDGE THAT TO THE MAXIMUM EXTENT PERMITTED BY
 *     APPLICABLE LAW, THIS SOFTWARE IS PROVIDED *AS IS* AND
 *     THAT NVIDIA AND ITS SUPPLIERS DISCLAIM ALL WARRANTIES,
 *     EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED
 *     TO, IMPLIED WARRANTIES OF MERCHANTABILITY  AND FITNESS
 *     FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL NVIDIA OR ITS SUPPLIERS BE LIABLE FOR ANY
 * SPECIAL, INCIDENTAL, INDIRECT, OR CONSEQUENTIAL DAMAGES
 * WHATSOEVER (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS
 * OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS
 * INFORMATION, OR ANY OTHER PECUNIARY LOSS), INCLUDING ATTORNEYS'
 * FEES, RELATING TO THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF NVIDIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 */

package demos.hwShadowmapsSimple;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import java.nio.*;
import java.util.*;
import javax.imageio.*;
import javax.swing.*;

import net.java.games.jogl.*;
import net.java.games.jogl.util.*;
import demos.util.*;
import gleem.*;
import gleem.linalg.*;

/** This demo is a simple illustration of ARB_shadow and ARB_depth_texture. <P>
    Cass Everitt <BR>
    12-11-00 <P>

    hw_shadowmaps_simple (c) 2001 NVIDIA Corporation <P>

    Ported to Java by Kenneth Russell
*/

public class HWShadowmapsSimple {
  private volatile boolean quit;

  private GLCanvas canvas;
  private GLPbuffer pbuffer;

  private GLUT glut;

  private float[] light_ambient   = { 0, 0, 0, 0 };
  private float[] light_intensity = { 1, 1, 1, 1 };
  private float[] light_pos       = { 0, 0, 0, 1 };

  static class Tweak {
    String name;
    float val;
    float incr;

    Tweak(String name, float val, float incr) {
      this.name = name;
      this.val = val;
      this.incr = incr;
    }
  };
  private java.util.List/*<Tweak>*/ tweaks = new ArrayList();
  private static final int R_COORDINATE_SCALE   = 0;
  private static final int R_COORDINATE_BIAS    = 1;
  private static final int POLYGON_OFFSET_SCALE = 2;
  private static final int POLYGON_OFFSET_BIAS  = 3;
  private int curr_tweak;

  // Texture objects
  private static final int TEX_SIZE = 1024;
  private int decal;
  private int light_image;
  private int light_view_depth;

  // Depth buffer format
  private int depth_format;

  private boolean fullyInitialized;

  // Display mode
  private static final int RENDER_SCENE_FROM_CAMERA_VIEW = 0;
  private static final int RENDER_SCENE_FROM_CAMERA_VIEW_SHADOWED = 1;
  private static final int RENDER_SCENE_FROM_LIGHT_VIEW = 2;
  private static final int NUM_DISPLAY_MODES = 3;
  private int displayMode = 1;

  // Display lists
  private int quad;
  private int wirecube;
  private int geometry;

  // Shadowing light
  private float lightshaper_fovy  = 60.0f;
  private float lightshaper_zNear = 0.5f;
  private float lightshaper_zFar  = 5.0f;

  // Manipulators
  private ExaminerViewer viewer;
  private boolean  doViewAll = true;
  //  private float    zNear = 0.5f;
  //  private float    zFar  = 5.0f;
  private float    zNear = 0.5f;
  private float    zFar  = 50.0f;
  private HandleBoxManip object;
  private HandleBoxManip spotlight;
  private Mat4f cameraPerspective = new Mat4f();
  private Mat4f cameraTransform = new Mat4f();
  private Mat4f cameraInverseTransform = new Mat4f();
  private Mat4f spotlightTransform = new Mat4f();
  private Mat4f spotlightInverseTransform = new Mat4f();
  private Mat4f objectTransform = new Mat4f();

  // Profiling
  private DurationTimer timer = new DurationTimer();
  private boolean  firstRender = true;
  private int      frameCount;

  public static void main(String[] args) {
    new HWShadowmapsSimple().run(args);
  }

  public void run(String[] args) {
    canvas = GLDrawableFactory.getFactory().createGLCanvas(new GLCapabilities());
    canvas.addGLEventListener(new Listener());
    canvas.setNoAutoRedrawMode(true);

    Frame frame = new Frame("ARB_shadow Shadows");
    frame.setLayout(new BorderLayout());
    canvas.setSize(512, 512);
    frame.add(canvas, BorderLayout.CENTER);
    frame.pack();
    frame.show();
    canvas.requestFocus();

    frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          quit = true;
        }
      });

    try {
      while (!quit) {
        if (viewer != null) {
          viewer.update();

          // Grab these values once per render to avoid multithreading
          // issues with their values being changed by manipulation from
          // the AWT thread during the render
          CameraParameters params = viewer.getCameraParameters();

          cameraPerspective.set(params.getProjectionMatrix());
          cameraInverseTransform.set(params.getModelviewMatrix());
          cameraTransform.set(cameraInverseTransform);
          cameraTransform.invertRigid();
          spotlightTransform.set(spotlight.getTransform());
          spotlightInverseTransform.set(spotlightTransform);
          spotlightInverseTransform.invertRigid();
          objectTransform.set(object.getTransform());
        }

        if (displayMode == RENDER_SCENE_FROM_CAMERA_VIEW_SHADOWED || !fullyInitialized) {
          if (pbuffer != null) {
            pbuffer.display();
          }
        }
        canvas.display();
      }
    } finally {
      System.exit(0);
    }
  }

  //----------------------------------------------------------------------
  // Internals only below this point
  //

  class Listener implements GLEventListener {

    public void init(GLDrawable drawable) {
      //      drawable.setGL(new DebugGL(drawable.getGL()));

      GL gl = drawable.getGL();
      GLU glu = drawable.getGLU();
      glut = new GLUT();

      try {
        checkExtension(gl, "GL_ARB_multitexture");
        checkExtension(gl, "GL_ARB_depth_texture");
        checkExtension(gl, "GL_ARB_shadow");
        checkExtension(gl, "GL_ARB_pbuffer");
        checkExtension(gl, "GL_ARB_pixel_format");
      } catch (GLException e) {
	e.printStackTrace();
        quit = true;
	throw(e);
      }
      
      gl.glClearColor(.5f, .5f, .5f, .5f);

      decal = genTexture(gl);
      gl.glBindTexture(GL.GL_TEXTURE_2D, decal);
      BufferedImage img = readPNGImage("demos/data/images/decal_image.png");
      makeRGBTexture(gl, glu, img, GL.GL_TEXTURE_2D, true);
      gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR_MIPMAP_LINEAR);
      gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);

      light_image = genTexture(gl);
      gl.glBindTexture(GL.GL_TEXTURE_2D, light_image);
      img = readPNGImage("demos/data/images/nvlogo_spot.png");
      makeRGBTexture(gl, glu, img, GL.GL_TEXTURE_2D, true);
      gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR);
      gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);
      gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP_TO_EDGE);
      gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP_TO_EDGE);

      quad = gl.glGenLists(1);
      gl.glNewList(quad, GL.GL_COMPILE);
      gl.glPushMatrix();
      gl.glRotatef(-90, 1, 0, 0);
      gl.glScalef(4,4,4);
      gl.glBegin(GL.GL_QUADS);
      gl.glNormal3f(0, 0, 1);
      gl.glVertex2f(-1, -1);
      gl.glVertex2f(-1,  1);
      gl.glVertex2f( 1,  1);
      gl.glVertex2f( 1, -1);
      gl.glEnd();
      gl.glPopMatrix();
      gl.glEndList();

      wirecube = gl.glGenLists(1);
      gl.glNewList(wirecube, GL.GL_COMPILE);
      glut.glutWireCube(gl, 2);
      gl.glEndList();

      geometry = gl.glGenLists(1);
      gl.glNewList(geometry, GL.GL_COMPILE);
      gl.glPushMatrix();
      //      gl.glTranslatef(0, .4f, 0);
      // FIXME
      //      glutSolidTeapot(.5f);
      glut.glutSolidTorus(gl, 0.25f, 0.5f, 40, 20);
      gl.glPopMatrix();
      gl.glEndList();

      gl.glEnable(GL.GL_LIGHT0);
      gl.glLightfv(GL.GL_LIGHT0, GL.GL_AMBIENT, light_ambient);
      gl.glLightfv(GL.GL_LIGHT0, GL.GL_DIFFUSE, light_intensity);
      gl.glLightfv(GL.GL_LIGHT0, GL.GL_SPECULAR, light_intensity);

      gl.glEnable(GL.GL_DEPTH_TEST);

      // init pbuffer
      GLCapabilities caps = new GLCapabilities();
      caps.setDoubleBuffered(false);
      pbuffer = drawable.createOffscreenDrawable(caps, TEX_SIZE, TEX_SIZE);
      pbuffer.addGLEventListener(new PbufferListener());

      // Register the window with the ManipManager
      ManipManager manager = ManipManager.getManipManager();
      manager.registerWindow(drawable);

      object = new HandleBoxManip();
      object.setTranslation(new Vec3f(0, 0.7f, 1.8f));
      object.setGeometryScale(new Vec3f(0.7f, 0.7f, 0.7f));
      manager.showManipInWindow(object, drawable);

      spotlight = new HandleBoxManip();
      spotlight.setScale(new Vec3f(0.5f, 0.5f, 0.5f));
      spotlight.setTranslation(new Vec3f(-0.25f, 2.35f, 5.0f));
      spotlight.setRotation(new Rotf(Vec3f.X_AXIS, (float) Math.toRadians(-30.0f)));
      manager.showManipInWindow(spotlight, drawable);

      viewer = new ExaminerViewer(MouseButtonHelper.numMouseButtons());
      viewer.attach(drawable, new BSphereProvider() {
	  public BSphere getBoundingSphere() {
	    return new BSphere(object.getTranslation(), 2.0f);
	  }
	});
      viewer.setOrientation(new Rotf(Vec3f.Y_AXIS, (float) Math.toRadians(45.0f)).times
                            (new Rotf(Vec3f.X_AXIS, (float) Math.toRadians(-15.0f))));
      viewer.setVertFOV((float) Math.toRadians(lightshaper_fovy / 2.0f));
      viewer.setZNear(zNear);
      viewer.setZFar(zFar);

      float bias = 1/((float) Math.pow(2.0,16.0)-1);

      tweaks.add(new Tweak("r coordinate scale",    0.5f, bias));
      tweaks.add(new Tweak("r coordinate bias",     0.5f, bias));
      tweaks.add(new Tweak("polygon offset scale",  2.5f, 0.5f));
      tweaks.add(new Tweak("polygon offset bias",  10.0f, 1.0f));

      drawable.addKeyListener(new KeyAdapter() {
          public void keyPressed(KeyEvent e) {
            dispatchKey(e.getKeyChar());
          }
        });
    }

    public void display(GLDrawable drawable) {
      if (quit) {
        return;
      }

      if (!fullyInitialized) {
        return;
      }

      if (!firstRender) {
        if (++frameCount == 30) {
          timer.stop();
          System.err.println("Frames per second: " + (30.0f / timer.getDurationAsSeconds()));
          timer.reset();
          timer.start();
          frameCount = 0;
        }
      } else {
        firstRender = false;
        timer.start();
      }

      GL gl = drawable.getGL();
      GLU glu = drawable.getGLU();

      gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

      if (doViewAll) {
	viewer.viewAll(gl);
	doViewAll = false;
        // Immediately zap effects
        gl.glMatrixMode(GL.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glMatrixMode(GL.GL_MODELVIEW);
        gl.glLoadIdentity();
      }

      CameraParameters params = viewer.getCameraParameters();

      switch (displayMode) {
        case RENDER_SCENE_FROM_CAMERA_VIEW:          render_scene_from_camera_view(gl, glu, drawable, params); break;
        case RENDER_SCENE_FROM_CAMERA_VIEW_SHADOWED: render_scene_from_camera_view_shadowed(gl, glu, drawable, params); break;
        case RENDER_SCENE_FROM_LIGHT_VIEW:           render_scene_from_light_view(gl, glu);           break;
        default: throw new RuntimeException("Illegal display mode " + displayMode);
      }
    }

    // Unused routines
    public void reshape(GLDrawable drawable, int x, int y, int width, int height) {}
    public void displayChanged(GLDrawable drawable, boolean modeChanged, boolean deviceChanged) {}

    //----------------------------------------------------------------------
    // Internals only below this point
    //

    private void checkExtension(GL gl, String extensionName) {
      if (!gl.isExtensionAvailable(extensionName)) {
        String message = "Unable to initialize " + extensionName + " OpenGL extension";
        JOptionPane.showMessageDialog(null, message, "Unavailable extension", JOptionPane.ERROR_MESSAGE);
	throw new GLException(message);
      }
    }

    private void dispatchKey(char k) {
      if ((k == (char) 27) || (k == 'q')) {
        quit = true;
	return;
      }

      switch (k) {
        case 27:
        case 'q':
          quit = true;
          break;

        case 'v':
          doViewAll = true;
          System.err.println("Forcing viewAll()");
          break;

        case ' ':
          displayMode = (displayMode + 1) % NUM_DISPLAY_MODES;
          System.err.println("Switching to display mode " + displayMode);
          break;

        // FIXME: add more key behaviors from original demo

        default:
          break;
      }
    }
  }

  class PbufferListener implements GLEventListener {
    public void init(GLDrawable drawable) {
      //      drawable.setGL(new DebugGL(drawable.getGL()));

      GL gl = drawable.getGL();
      GLU glu = drawable.getGLU();

      gl.glEnable(GL.GL_DEPTH_TEST);

      int[] depth_bits = new int[1];
      gl.glGetIntegerv(GL.GL_DEPTH_BITS, depth_bits);
        
      if (depth_bits[0] == 16)  depth_format = GL.GL_DEPTH_COMPONENT16_ARB;
      else                      depth_format = GL.GL_DEPTH_COMPONENT24_ARB;

      light_view_depth = genTexture(gl);
      gl.glBindTexture(GL.GL_TEXTURE_2D, light_view_depth);
      gl.glTexImage2D(GL.GL_TEXTURE_2D, 0, depth_format, TEX_SIZE, TEX_SIZE, 0, 
                      GL.GL_DEPTH_COMPONENT, GL.GL_UNSIGNED_INT, (byte[]) null);
      set_light_view_texture_parameters(gl);

      fullyInitialized = true;
    }

    public void display(GLDrawable drawable) {
      GL gl = drawable.getGL();
      GLU glu = drawable.getGLU();

      gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

      gl.glPolygonOffset(((Tweak) tweaks.get(POLYGON_OFFSET_SCALE)).val,
                         ((Tweak) tweaks.get(POLYGON_OFFSET_BIAS)).val);
      gl.glEnable(GL.GL_POLYGON_OFFSET_FILL);

      render_scene_from_light_view(gl, glu);

      gl.glDisable(GL.GL_POLYGON_OFFSET_FILL);
    
      gl.glBindTexture(GL.GL_TEXTURE_2D, light_view_depth);

      // trying different ways of getting the depth info over
      gl.glCopyTexSubImage2D(GL.GL_TEXTURE_2D, 0,   0, 0,   0, 0,  TEX_SIZE, TEX_SIZE);
    }

    // Unused routines
    public void reshape(GLDrawable drawable, int x, int y, int width, int height) {}
    public void displayChanged(GLDrawable drawable, boolean modeChanged, boolean deviceChanged) {}
  }

  private void set_light_view_texture_parameters(GL gl) {
    gl.glBindTexture(GL.GL_TEXTURE_2D, light_view_depth);
    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR);
    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);
    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP_TO_EDGE);
    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP_TO_EDGE);
    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_COMPARE_MODE_ARB, GL.GL_COMPARE_R_TO_TEXTURE_ARB);
    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_COMPARE_FUNC_ARB, GL.GL_LEQUAL);
  }

  private int genTexture(GL gl) {
    int[] tmp = new int[1];
    gl.glGenTextures(1, tmp);
    return tmp[0];
  }

  private BufferedImage readPNGImage(String resourceName) {
    try {
      BufferedImage img = ImageIO.read(getClass().getClassLoader().getResourceAsStream(resourceName));
      if (img == null) {
        throw new RuntimeException("Error reading resource " + resourceName);
      }
      return img;
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  private void makeRGBTexture(GL gl, GLU glu, BufferedImage img, int target, boolean mipmapped) {
    ByteBuffer dest = null;
    switch (img.getType()) {
    case BufferedImage.TYPE_3BYTE_BGR:
    case BufferedImage.TYPE_CUSTOM: {
      byte[] data = ((DataBufferByte) img.getRaster().getDataBuffer()).getData();
      dest = ByteBuffer.allocateDirect(data.length);
      dest.order(ByteOrder.nativeOrder());
      dest.put(data, 0, data.length);
      break;
    }

    case BufferedImage.TYPE_INT_RGB: {
      int[] data = ((DataBufferInt) img.getRaster().getDataBuffer()).getData();
      dest = ByteBuffer.allocateDirect(data.length * BufferUtils.SIZEOF_INT);
      dest.order(ByteOrder.nativeOrder());
      dest.asIntBuffer().put(data, 0, data.length);
      break;
    }

    default:
      throw new RuntimeException("Unsupported image type " + img.getType());
    }

    if (mipmapped) {
      glu.gluBuild2DMipmaps(target, GL.GL_RGB8, img.getWidth(), img.getHeight(), GL.GL_RGB,
                            GL.GL_UNSIGNED_BYTE, dest);
    } else {
      gl.glTexImage2D(target, 0, GL.GL_RGB, img.getWidth(), img.getHeight(), 0,
                      GL.GL_RGB, GL.GL_UNSIGNED_BYTE, dest);
    }
  }

  private void eye_linear_texgen(GL gl) {
    Mat4f m = new Mat4f();
    m.makeIdent();

    set_texgen_planes(gl, GL.GL_EYE_PLANE, m);
    gl.glTexGeni(GL.GL_S, GL.GL_TEXTURE_GEN_MODE, GL.GL_EYE_LINEAR);
    gl.glTexGeni(GL.GL_T, GL.GL_TEXTURE_GEN_MODE, GL.GL_EYE_LINEAR);
    gl.glTexGeni(GL.GL_R, GL.GL_TEXTURE_GEN_MODE, GL.GL_EYE_LINEAR);
    gl.glTexGeni(GL.GL_Q, GL.GL_TEXTURE_GEN_MODE, GL.GL_EYE_LINEAR);
  }

  private void obj_linear_texgen(GL gl) {
    Mat4f m = new Mat4f();
    m.makeIdent();

    set_texgen_planes(gl, GL.GL_OBJECT_PLANE, m);
    gl.glTexGeni(GL.GL_S, GL.GL_TEXTURE_GEN_MODE, GL.GL_OBJECT_LINEAR);
    gl.glTexGeni(GL.GL_T, GL.GL_TEXTURE_GEN_MODE, GL.GL_OBJECT_LINEAR);
    gl.glTexGeni(GL.GL_R, GL.GL_TEXTURE_GEN_MODE, GL.GL_OBJECT_LINEAR);
    gl.glTexGeni(GL.GL_Q, GL.GL_TEXTURE_GEN_MODE, GL.GL_OBJECT_LINEAR);
  }

  private void set_texgen_planes(GL gl, int plane_type, Mat4f m) {
    int[] coord = {GL.GL_S, GL.GL_T, GL.GL_R, GL.GL_Q};
    float[] row = new float[4];
    for(int i = 0; i < 4; i++) {
      getRow(m, i, row);
      gl.glTexGenfv(coord[i], plane_type, row);
    }
  }

  private void texgen(GL gl, boolean enable) {
    if(enable) {
      gl.glEnable(GL.GL_TEXTURE_GEN_S);
      gl.glEnable(GL.GL_TEXTURE_GEN_T);
      gl.glEnable(GL.GL_TEXTURE_GEN_R);
      gl.glEnable(GL.GL_TEXTURE_GEN_Q);
    } else {
      gl.glDisable(GL.GL_TEXTURE_GEN_S);
      gl.glDisable(GL.GL_TEXTURE_GEN_T);
      gl.glDisable(GL.GL_TEXTURE_GEN_R);
      gl.glDisable(GL.GL_TEXTURE_GEN_Q);
    }
  }

  private void render_light_frustum(GL gl) {
    gl.glPushMatrix();
    applyTransform(gl, cameraInverseTransform);
    applyTransform(gl, spotlightTransform);
    applyTransform(gl, perspectiveInverse(lightshaper_fovy, 1, lightshaper_zNear, lightshaper_zFar));
    gl.glDisable(GL.GL_LIGHTING);
    gl.glColor3f(1,1,0);
    gl.glCallList(wirecube);
    gl.glColor3f(1,1,1);
    gl.glEnable(GL.GL_LIGHTING);
    gl.glPopMatrix();
  }

  private void render_quad(GL gl) {
    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);
    obj_linear_texgen(gl);
    texgen(gl, true);
    gl.glMatrixMode(GL.GL_TEXTURE);
    gl.glLoadIdentity();
    gl.glScalef(4,4,1);
    gl.glMatrixMode(GL.GL_MODELVIEW);

    gl.glDisable(GL.GL_LIGHTING);
    gl.glBindTexture(GL.GL_TEXTURE_2D, decal);
    gl.glEnable(GL.GL_TEXTURE_2D);
    gl.glCallList(quad);
    gl.glDisable(GL.GL_TEXTURE_2D);
    gl.glEnable(GL.GL_LIGHTING);

    texgen(gl, false);
    gl.glMatrixMode(GL.GL_TEXTURE);
    gl.glLoadIdentity();
    gl.glMatrixMode(GL.GL_MODELVIEW);
  }

  private void render_scene(GL gl, Mat4f view, GLDrawable drawable, CameraParameters params) {
    gl.glColor3f(1,1,1);
    gl.glPushMatrix();
    Mat4f inverseView = new Mat4f(view);
    inverseView.invertRigid();
    applyTransform(gl, inverseView);

    gl.glPushMatrix();
    render_quad(gl);

    applyTransform(gl, objectTransform);

    gl.glEnable(GL.GL_LIGHTING);
    gl.glCallList(geometry);
    gl.glDisable(GL.GL_LIGHTING);

    gl.glPopMatrix();

    gl.glPopMatrix();
  }

  private void render_manipulators(GL gl, Mat4f view, GLDrawable drawable, CameraParameters params) {
    gl.glColor3f(1,1,1);
    gl.glPushMatrix();
    Mat4f inverseView = new Mat4f(view);
    inverseView.invertRigid();
    applyTransform(gl, inverseView);

    if (params != null) {
      ManipManager.getManipManager().updateCameraParameters(drawable, params);
      ManipManager.getManipManager().render(drawable, gl);
    }

    gl.glPopMatrix();
  }

  private void render_scene_from_camera_view(GL gl, GLU glu, GLDrawable drawable, CameraParameters params) {
    // place light
    gl.glPushMatrix();
    gl.glLoadIdentity();
    applyTransform(gl, cameraInverseTransform);
    applyTransform(gl, spotlightTransform);
    gl.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION, light_pos);
    gl.glPopMatrix();

    // spot image
    gl.glActiveTextureARB(GL.GL_TEXTURE1_ARB);

    gl.glPushMatrix();
    applyTransform(gl, cameraInverseTransform);
    eye_linear_texgen(gl);    
    texgen(gl, true);
    gl.glPopMatrix();

    gl.glMatrixMode(GL.GL_TEXTURE);
    gl.glLoadIdentity();
    gl.glTranslatef(.5f, .5f, .5f);
    gl.glScalef(.5f, .5f, .5f);
    glu.gluPerspective(lightshaper_fovy, 1, lightshaper_zNear, lightshaper_zFar);
    applyTransform(gl, spotlightInverseTransform);
    gl.glMatrixMode(GL.GL_MODELVIEW);

    gl.glBindTexture(GL.GL_TEXTURE_2D, light_image);
    gl.glEnable(GL.GL_TEXTURE_2D);
    gl.glTexEnvi(GL.GL_TEXTURE_ENV, GL.GL_TEXTURE_ENV_MODE, GL.GL_MODULATE);

    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);
    gl.glMatrixMode(GL.GL_PROJECTION);
    gl.glLoadIdentity();
    gl.glViewport(0, 0, canvas.getWidth(), canvas.getHeight());
    applyTransform(gl, cameraPerspective);
    gl.glMatrixMode(GL.GL_MODELVIEW);
    render_scene(gl, cameraTransform, drawable, params);

    gl.glActiveTextureARB(GL.GL_TEXTURE1_ARB);
    gl.glDisable(GL.GL_TEXTURE_2D);
    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);

    render_manipulators(gl, cameraTransform, drawable, params);

    render_light_frustum(gl);
  }

  private void render_scene_from_camera_view_shadowed(GL gl, GLU glu, GLDrawable drawable, CameraParameters params) {
    // place light
    gl.glPushMatrix();
    gl.glLoadIdentity();
    applyTransform(gl, cameraInverseTransform);
    applyTransform(gl, spotlightTransform);
    gl.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION, light_pos);
    gl.glPopMatrix();

    // spot image
    gl.glActiveTextureARB(GL.GL_TEXTURE1_ARB);

    gl.glPushMatrix();
    applyTransform(gl, cameraInverseTransform);
    eye_linear_texgen(gl);    
    texgen(gl, true);
    gl.glPopMatrix();

    gl.glMatrixMode(GL.GL_TEXTURE);
    gl.glLoadIdentity();
    gl.glTranslatef(.5f, .5f, .5f);
    gl.glScalef(.5f, .5f, .5f);
    glu.gluPerspective(lightshaper_fovy, 1, lightshaper_zNear, lightshaper_zFar);
    applyTransform(gl, spotlightInverseTransform);
    gl.glMatrixMode(GL.GL_MODELVIEW);

    gl.glBindTexture(GL.GL_TEXTURE_2D, light_image);
    gl.glEnable(GL.GL_TEXTURE_2D);
    gl.glTexEnvi(GL.GL_TEXTURE_ENV, GL.GL_TEXTURE_ENV_MODE, GL.GL_MODULATE);

    // depth compare
    gl.glActiveTextureARB(GL.GL_TEXTURE2_ARB);

    gl.glPushMatrix();
    applyTransform(gl, cameraInverseTransform);
    eye_linear_texgen(gl);    
    texgen(gl, true);
    gl.glPopMatrix();

    gl.glMatrixMode(GL.GL_TEXTURE);
    gl.glLoadIdentity();
    gl.glTranslatef(.5f, .5f, ((Tweak) tweaks.get(R_COORDINATE_SCALE)).val);
    gl.glScalef(.5f, .5f, ((Tweak) tweaks.get(R_COORDINATE_BIAS)).val);
    glu.gluPerspective(lightshaper_fovy, 1, lightshaper_zNear, lightshaper_zFar);
    applyTransform(gl, spotlightInverseTransform);
    gl.glMatrixMode(GL.GL_MODELVIEW);

    gl.glBindTexture(GL.GL_TEXTURE_2D, light_view_depth);
    gl.glEnable(GL.GL_TEXTURE_2D);
    gl.glTexEnvi(GL.GL_TEXTURE_ENV, GL.GL_TEXTURE_ENV_MODE, GL.GL_MODULATE);
    
    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);

    gl.glMatrixMode(GL.GL_PROJECTION);
    gl.glLoadIdentity();
    gl.glViewport(0, 0, canvas.getWidth(), canvas.getHeight());
    applyTransform(gl, cameraPerspective);
    gl.glMatrixMode(GL.GL_MODELVIEW);
    render_scene(gl, cameraTransform, drawable, params);

    gl.glActiveTextureARB(GL.GL_TEXTURE1_ARB);
    gl.glDisable(GL.GL_TEXTURE_2D);
    gl.glActiveTextureARB(GL.GL_TEXTURE2_ARB);
    gl.glDisable(GL.GL_TEXTURE_2D);
    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);

    render_manipulators(gl, cameraTransform, drawable, params);

    render_light_frustum(gl);
  }

  private void largest_square_power_of_two_viewport(GL gl) {
    Dimension dim = canvas.getSize();
    float min = Math.min(dim.width, dim.height);
    float log2min = (float) Math.log(min) / (float) Math.log(2.0);
    float pow2 = (float) Math.floor(log2min);
    int size = 1 << (int) pow2;
    gl.glViewport(0, 0, size, size);
  }

  private void render_scene_from_light_view(GL gl, GLU glu) {
    // place light
    gl.glPushMatrix();
    gl.glLoadIdentity();
    gl.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION, light_pos);
    gl.glPopMatrix();

    // spot image
    gl.glActiveTextureARB(GL.GL_TEXTURE1_ARB);

    gl.glPushMatrix();
    eye_linear_texgen(gl);    
    texgen(gl, true);
    gl.glPopMatrix();

    gl.glMatrixMode(GL.GL_TEXTURE);
    gl.glLoadIdentity();
    gl.glTranslatef(.5f, .5f, .5f);
    gl.glScalef(.5f, .5f, .5f);
    glu.gluPerspective(lightshaper_fovy, 1, lightshaper_zNear, lightshaper_zFar);
    gl.glMatrixMode(GL.GL_MODELVIEW);

    gl.glBindTexture(GL.GL_TEXTURE_2D, light_image);
    gl.glEnable(GL.GL_TEXTURE_2D);
    gl.glTexEnvi(GL.GL_TEXTURE_ENV, GL.GL_TEXTURE_ENV_MODE, GL.GL_MODULATE);

    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);

    gl.glViewport(0, 0, TEX_SIZE, TEX_SIZE);
    gl.glMatrixMode(GL.GL_PROJECTION);
    gl.glLoadIdentity();
    glu.gluPerspective(lightshaper_fovy, 1, lightshaper_zNear, lightshaper_zFar);
    gl.glMatrixMode(GL.GL_MODELVIEW);
    if (displayMode == RENDER_SCENE_FROM_LIGHT_VIEW)
      largest_square_power_of_two_viewport(gl);
    render_scene(gl, spotlightTransform, null, null);

    gl.glActiveTextureARB(GL.GL_TEXTURE1_ARB);
    gl.glDisable(GL.GL_TEXTURE_2D);
    gl.glActiveTextureARB(GL.GL_TEXTURE0_ARB);
  }

  private static void getRow(Mat4f m, int row, float[] out) {
    out[0] = m.get(row, 0);
    out[1] = m.get(row, 1);
    out[2] = m.get(row, 2);
    out[3] = m.get(row, 3);
  }

  private static void applyTransform(GL gl, Mat4f xform) {
    float[] data = new float[16];
    xform.getColumnMajorData(data);
    gl.glMultMatrixf(data);
  }

  private static Mat4f perspectiveInverse(float fovy, float aspect, float zNear, float zFar) {
    float tangent = (float) Math.tan(Math.toRadians(fovy / 2.0));
    float y = tangent * zNear;
    float x = aspect * y;
    return frustumInverse(-x, x, -y, y, zNear, zFar);
  }

  private static Mat4f frustumInverse(float left, float right,
                               float bottom, float top,
                               float zNear, float zFar) {
    Mat4f m = new Mat4f();
    m.makeIdent();

    m.set(0, 0, (right - left) / (2 * zNear));
    m.set(0, 3, (right + left) / (2 * zNear));
	
    m.set(1, 1, (top - bottom) / (2 * zNear));
    m.set(1, 3, (top + bottom) / (2 * zNear));

    m.set(2, 2,  0);
    m.set(2, 3, -1);
	
    m.set(3, 2, -(zFar - zNear) / (2 * zFar * zNear));
    m.set(3, 3,  (zFar + zNear) / (2 * zFar * zNear));

    return m;
  }
}