summaryrefslogtreecommitdiffstats
path: root/src/classes/javax/media/opengl/GLJPanel.java
blob: e69c03c2f68f019c112132d10ef8e15e58175710 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
/*
 * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package javax.media.opengl;

import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.beans.*;
import javax.swing.*;
import java.nio.*;
import java.security.*;
import javax.swing.JComponent;
import javax.swing.JPanel;
import com.sun.opengl.impl.*;

// FIXME: Subclasses need to call resetGLFunctionAvailability() on their
// context whenever the displayChanged() function is called on their
// GLEventListeners

/** A lightweight Swing component which provides OpenGL rendering
    support. Provided for compatibility with Swing user interfaces
    when adding a heavyweight doesn't work either because of
    Z-ordering or LayoutManager problems. <P>

    The GLJPanel can be made transparent by creating it with a
    GLCapabilities object with alpha bits specified and calling {@link
    #setOpaque}(false). Pixels with resulting OpenGL alpha values less
    than 1.0 will be overlaid on any underlying Swing rendering. <P>

    Notes specific to the Reference Implementation: This component 
    attempts to use hardware-accelerated rendering via pbuffers and 
    falls back on to software rendering if problems occur. 
    Note that because this component attempts to use pbuffers for
    rendering, and because pbuffers can not be resized, somewhat
    surprising behavior may occur during resize operations; the {@link
    GLEventListener#init} method may be called multiple times as the
    pbuffer is resized to be able to cover the size of the GLJPanel.
    This behavior is correct, as the textures and display lists for
    the GLJPanel will have been lost during the resize operation. The
    application should attempt to make its GLEventListener.init()
    methods as side-effect-free as possible. <P>

*/

public class GLJPanel extends JPanel implements GLAutoDrawable {
  private static final boolean DEBUG = Debug.debug("GLJPanel");
  private static final boolean VERBOSE = Debug.verbose();

  private GLDrawableHelper drawableHelper = new GLDrawableHelper();
  private volatile boolean isInitialized;
  private volatile boolean shouldInitialize = false;

  // Data used for either pbuffers or pixmap-based offscreen surfaces
  private GLCapabilities        offscreenCaps;
  private GLCapabilitiesChooser chooser;
  private GLContext             shareWith;
  // This image is exactly the correct size to render into the panel
  private BufferedImage         offscreenImage;
  // One of these is used to store the read back pixels before storing
  // in the BufferedImage
  private ByteBuffer            readBackBytes;
  private IntBuffer             readBackInts;
  private int                   readBackWidthInPixels;
  private int                   readBackHeightInPixels;
  // Width of the actual GLJPanel
  private int panelWidth   = 0;
  private int panelHeight  = 0;
  private Updater updater;
  private int awtFormat;
  private int glFormat;
  private int glType;
  // Lazy reshape notification
  private boolean handleReshape = false;
  private boolean sendReshape = true;

  // Implementation using pbuffers
  private static boolean hardwareAccelerationDisabled =
    Debug.isPropertyDefined("jogl.gljpanel.nohw");
  private static boolean softwareRenderingDisabled =
    Debug.isPropertyDefined("jogl.gljpanel.nosw");
  private GLPbuffer pbuffer;
  private int       pbufferWidth  = 256;
  private int       pbufferHeight = 256;

  // Implementation using software rendering
  private GLDrawableImpl offscreenDrawable;
  private GLContextImpl offscreenContext;

  // For handling reshape events lazily
  private int reshapeX;
  private int reshapeY;
  private int reshapeWidth;
  private int reshapeHeight;

  // For saving/restoring of OpenGL state during ReadPixels
  private int[] swapbytes    = new int[1];
  private int[] rowlength    = new int[1];
  private int[] skiprows     = new int[1];
  private int[] skippixels   = new int[1];
  private int[] alignment    = new int[1];

  // Implementation using Java2D OpenGL pipeline's back buffer
  private boolean oglPipelineEnabled =
    Java2D.isOGLPipelineActive() &&
    !Debug.isPropertyDefined("jogl.gljpanel.noogl");
  // Opaque Object identifier representing the Java2D surface we are
  // drawing to; used to determine when to destroy and recreate JOGL
  // context
  private Object j2dSurface;
  // Graphics object being used during Java2D update action
  // (absolutely essential to cache this)
  private Graphics cached2DGraphics;
  // No-op context representing the Java2D OpenGL context
  private GLContext j2dContext;
  // Context associated with no-op drawable representing the JOGL
  // OpenGL context
  private GLDrawable joglDrawable;
  // The real OpenGL context JOGL uses to render
  private GLContext  joglContext;
  // State captured from Java2D OpenGL context necessary in order to
  // properly render into Java2D back buffer
  private int[] drawBuffer   = new int[1];
  private int[] readBuffer   = new int[1];
  // This is required when the FBO option of the Java2D / OpenGL
  // pipeline is active
  private int[] frameBuffer  = new int[1];
  // Current (as of this writing) NVidia drivers have a couple of bugs
  // relating to the sharing of framebuffer and renderbuffer objects
  // between contexts. It appears we have to (a) reattach the color
  // attachment and (b) actually create new depth buffer storage and
  // attach it in order for the FBO to behave properly in our context.
  private boolean checkedForFBObjectWorkarounds;
  private boolean fbObjectWorkarounds;
  private int[] frameBufferDepthBuffer;
  private int[] frameBufferTexture;
  private boolean createNewDepthBuffer;
  // Current (as of this writing) ATI drivers have problems when the
  // same FBO is bound in two different contexts. Here we check for
  // this case and explicitly release the FBO from Java2D's context
  // before switching to ours. Java2D will re-bind the FBO when it
  // makes its context current the next time. Interestingly, if we run
  // this code path on NVidia hardware, it breaks the rendering
  // results -- no output is generated. This doesn't appear to be an
  // interaction with the abovementioned NVidia-specific workarounds,
  // as even if we disable that code the FBO is still reported as
  // incomplete in our context.
  private boolean checkedGLVendor;
  private boolean vendorIsATI;

  // These are always set to (0, 0) except when the Java2D / OpenGL
  // pipeline is active
  private int   viewportX;
  private int   viewportY;

  static {
    // Force eager initialization of part of the Java2D class since
    // otherwise it's likely it will try to be initialized while on
    // the Queue Flusher Thread, which is not allowed
    if (Java2D.isOGLPipelineActive() && Java2D.isFBOEnabled()) {
      Java2D.getShareContext(GraphicsEnvironment.
                             getLocalGraphicsEnvironment().
                             getDefaultScreenDevice().
                             getDefaultConfiguration());
    }
  }

  /** Creates a new GLJPanel component with a default set of OpenGL
      capabilities and using the default OpenGL capabilities selection
      mechanism. */
  public GLJPanel() {
    this(null);
  }

  /** Creates a new GLJPanel component with the requested set of
      OpenGL capabilities, using the default OpenGL capabilities
      selection mechanism. */
  public GLJPanel(GLCapabilities capabilities) {
    this(capabilities, null, null);
  }

  /** Creates a new GLJPanel component. The passed GLCapabilities
      specifies the OpenGL capabilities for the component; if null, a
      default set of capabilities is used. The GLCapabilitiesChooser
      specifies the algorithm for selecting one of the available
      GLCapabilities for the component; a DefaultGLCapabilitesChooser
      is used if null is passed for this argument. The passed
      GLContext specifies an OpenGL context with which to share
      textures, display lists and other OpenGL state, and may be null
      if sharing is not desired. See the note in the overview documentation on
      <a href="../../../overview-summary.html#SHARING">context sharing</a>.
  */
  public GLJPanel(GLCapabilities capabilities, GLCapabilitiesChooser chooser, GLContext shareWith) {
    super();

    // Works around problems on many vendors' cards; we don't need a
    // back buffer for the offscreen surface anyway
    if (capabilities != null) {
        offscreenCaps = (GLCapabilities) capabilities.clone();
    } else {
        offscreenCaps = new GLCapabilities();
    }
    offscreenCaps.setDoubleBuffered(false);
    this.chooser = ((chooser != null) ? chooser : new DefaultGLCapabilitiesChooser());
    this.shareWith = shareWith;
  }

  public void display() {
    if (EventQueue.isDispatchThread()) {
      // Want display() to be synchronous, so call paintImmediately()
      paintImmediately(0, 0, getWidth(), getHeight());
    } else {
      // Multithreaded redrawing of Swing components is not allowed,
      // so do everything on the event dispatch thread
      try {
        EventQueue.invokeAndWait(paintImmediatelyAction);
      } catch (Exception e) {
        throw new GLException(e);
      }
    }
  }

  private void captureJ2DState(GL gl, Graphics g) {
    gl.glGetIntegerv(GL.GL_DRAW_BUFFER, drawBuffer, 0);
    gl.glGetIntegerv(GL.GL_READ_BUFFER, readBuffer, 0);
    if (Java2D.isFBOEnabled() &&
        Java2D.getOGLSurfaceType(g) == Java2D.FBOBJECT) {
      if (DEBUG && VERBOSE) {
        System.err.println("GLJPanel: Fetching GL_FRAMEBUFFER_BINDING_EXT");
      }
      gl.glGetIntegerv(GL.GL_FRAMEBUFFER_BINDING_EXT, frameBuffer, 0);

      if (fbObjectWorkarounds ||
          !checkedForFBObjectWorkarounds) {
        // See above for description of what we are doing here
        if (frameBufferTexture == null)
          frameBufferTexture = new int[1];

        // Query the framebuffer for its color buffer so we can hook
        // it back up in our context (should not be necessary)
        gl.glGetFramebufferAttachmentParameterivEXT(GL.GL_FRAMEBUFFER_EXT,
                                                    GL.GL_COLOR_ATTACHMENT0_EXT,
                                                    GL.GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
                                                    frameBufferTexture, 0);
        if (DEBUG && VERBOSE) {
          System.err.println("GLJPanel: FBO COLOR_ATTACHMENT0: " + frameBufferTexture[0]);
        }
      }

      if (!checkedGLVendor) {
        checkedGLVendor = true;
        String vendor = gl.glGetString(GL.GL_VENDOR);

        if ((vendor != null) &&
            vendor.startsWith("ATI")) {
          vendorIsATI = true;
        }
      }

      if (vendorIsATI) {
        // Unbind the FBO from Java2D's context as it appears that
        // driver bugs on ATI's side are causing problems if the FBO is
        // simultaneously bound to more than one context. Java2D will
        // re-bind the FBO during the next validation of its context.
        // Note: this breaks rendering at least on NVidia hardware
        gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, 0);
      }
    }
  }

  private boolean preGL(Graphics g) {
    GL gl = joglContext.getGL();
    // Set up needed state in JOGL context from Java2D context
    gl.glEnable(GL.GL_SCISSOR_TEST);
    Rectangle r = Java2D.getOGLScissorBox(g);

    if (r == null) {
      if (DEBUG && VERBOSE) {
        System.err.println("Java2D.getOGLScissorBox() returned null");
      }
      return false;
    }
    if (DEBUG && VERBOSE) {
      System.err.println("GLJPanel: gl.glScissor(" + r.x + ", " + r.y + ", " + r.width + ", " + r.height + ")");
    }

    gl.glScissor(r.x, r.y, r.width, r.height);
    Rectangle oglViewport = Java2D.getOGLViewport(g, panelWidth, panelHeight);
    // If the viewport X or Y changes, in addition to the panel's
    // width or height, we need to send a reshape operation to the
    // client
    if ((viewportX != oglViewport.x) ||
        (viewportY != oglViewport.y)) {
      sendReshape = true;
      if (DEBUG) {
        System.err.println("Sending reshape because viewport changed");
        System.err.println("  viewportX (" + viewportX + ") ?= oglViewport.x (" + oglViewport.x + ")");
        System.err.println("  viewportY (" + viewportY + ") ?= oglViewport.y (" + oglViewport.y + ")");
      }
    }
    viewportX = oglViewport.x;
    viewportY = oglViewport.y;

    // If the FBO option is active, bind to the FBO from the Java2D
    // context.
    // Note that all of the plumbing in the context sharing stuff will
    // allow us to bind to this object since it's in our namespace.
    if (Java2D.isFBOEnabled() &&
        Java2D.getOGLSurfaceType(g) == Java2D.FBOBJECT) {
      if (DEBUG && VERBOSE) {
        System.err.println("GLJPanel: Binding to framebuffer object " + frameBuffer[0]);
      }

      // The texture target for Java2D's OpenGL pipeline when using FBOs
      // -- either GL_TEXTURE_2D or GL_TEXTURE_RECTANGLE_ARB
      int fboTextureTarget = Java2D.getOGLTextureType(g);

      if (!checkedForFBObjectWorkarounds) {
        checkedForFBObjectWorkarounds = true;
        gl.glBindTexture(fboTextureTarget, 0);
        gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, frameBuffer[0]);
        if (gl.glCheckFramebufferStatusEXT(GL.GL_FRAMEBUFFER_EXT) !=
            GL.GL_FRAMEBUFFER_COMPLETE_EXT) {
          // Need to do workarounds
          fbObjectWorkarounds = true;
          createNewDepthBuffer = true;
          if (DEBUG) {
            System.err.println("-- GLJPanel: discovered frame_buffer_object workarounds to be necessary");
          }
        } else {
          // Don't need the frameBufferTexture temporary any more
          frameBufferTexture = null;
        }
      }

      if (fbObjectWorkarounds && createNewDepthBuffer) {
        if (frameBufferDepthBuffer == null)
          frameBufferDepthBuffer = new int[1];

        // Create our own depth renderbuffer and associated storage
        // If we have an old one, delete it
        if (frameBufferDepthBuffer[0] != 0) {
          gl.glDeleteRenderbuffersEXT(1, frameBufferDepthBuffer, 0);
          frameBufferDepthBuffer[0] = 0;
        }

        gl.glBindTexture(fboTextureTarget, frameBufferTexture[0]);
        int[] width = new int[1];
        int[] height = new int[1];
        gl.glGetTexLevelParameteriv(fboTextureTarget, 0, GL.GL_TEXTURE_WIDTH, width, 0);
        gl.glGetTexLevelParameteriv(fboTextureTarget, 0, GL.GL_TEXTURE_HEIGHT, height, 0);
                    
        gl.glGenRenderbuffersEXT(1, frameBufferDepthBuffer, 0);
        if (DEBUG) {
          System.err.println("GLJPanel: Generated frameBufferDepthBuffer " + frameBufferDepthBuffer[0] +
                             " with width " + width[0] + ", height " + height[0]);
        }
                    
        gl.glBindRenderbufferEXT(GL.GL_RENDERBUFFER_EXT, frameBufferDepthBuffer[0]);
        // FIXME: may need a loop here like in Java2D
        gl.glRenderbufferStorageEXT(GL.GL_RENDERBUFFER_EXT, GL.GL_DEPTH_COMPONENT24, width[0], height[0]);

        gl.glBindRenderbufferEXT(GL.GL_RENDERBUFFER_EXT, 0);
        createNewDepthBuffer = false;
      }

      gl.glBindTexture(fboTextureTarget, 0);
      gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, frameBuffer[0]);

      if (fbObjectWorkarounds) {
        // Hook up the color and depth buffer attachment points for this framebuffer
        gl.glFramebufferTexture2DEXT(GL.GL_FRAMEBUFFER_EXT,
                                     GL.GL_COLOR_ATTACHMENT0_EXT,
                                     fboTextureTarget,
                                     frameBufferTexture[0],
                                     0);
        if (DEBUG && VERBOSE) {
          System.err.println("GLJPanel: frameBufferDepthBuffer: " + frameBufferDepthBuffer[0]);
        }
        gl.glFramebufferRenderbufferEXT(GL.GL_FRAMEBUFFER_EXT,
                                        GL.GL_DEPTH_ATTACHMENT_EXT,
                                        GL.GL_RENDERBUFFER_EXT,
                                        frameBufferDepthBuffer[0]);
      }

      if (DEBUG) {
        int status = gl.glCheckFramebufferStatusEXT(GL.GL_FRAMEBUFFER_EXT);
        if (status != GL.GL_FRAMEBUFFER_COMPLETE_EXT) {
          throw new GLException("Error: framebuffer was incomplete: status = 0x" +
                                Integer.toHexString(status));
        }
      }
    } else {
      if (DEBUG && VERBOSE) {
        System.err.println("GLJPanel: Setting up drawBuffer " + drawBuffer[0] +
                           " and readBuffer " + readBuffer[0]);
      }

      gl.glDrawBuffer(drawBuffer[0]);
      gl.glReadBuffer(readBuffer[0]);
    }

    return true;
  }

  private void postGL(Graphics g) {
    if (Java2D.isFBOEnabled() &&
        Java2D.getOGLSurfaceType(g) == Java2D.FBOBJECT) {
      // Unbind the framebuffer from our context to work around
      // apparent driver bugs or at least unspecified behavior causing
      // OpenGL to run out of memory with certain cards and drivers
      GL gl = joglContext.getGL();
      gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, 0);
    }
  }

  /** Overridden to cause OpenGL rendering to be performed during
      repaint cycles. Subclasses which override this method must call
      super.paintComponent() in their paintComponent() method in order
      to function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>paintComponent</CODE> in class <CODE>javax.swing.JComponent</CODE></DD></DL> */
  protected void paintComponent(final Graphics g) {
    if (shouldInitialize) {
      initialize();
    }

    if (!isInitialized) {
      return;
    }

    // NOTE: must do this when the context is not current as it may
    // involve destroying the pbuffer (current context) and
    // re-creating it -- tricky to do properly while the context is
    // current
    if (handleReshape) {
      handleReshape();
    }

    updater.setGraphics(g);

    if (oglPipelineEnabled) {
      Java2D.invokeWithOGLContextCurrent(g, new Runnable() {
          public void run() {
            if (DEBUG && VERBOSE) {
              System.err.println("-- In invokeWithOGLContextCurrent");
            }

            // Create no-op context representing Java2D context
            if (j2dContext == null) {
              j2dContext = GLDrawableFactory.getFactory().createExternalGLContext();
              if (DEBUG) {
                j2dContext.setGL(new DebugGL(j2dContext.getGL()));
              }

              // Check to see whether we can support the requested
              // capabilities or need to fall back to a pbuffer
              // FIXME: add more checks?

              j2dContext.makeCurrent();
              GL gl = j2dContext.getGL();
              if ((getGLInteger(gl, GL.GL_RED_BITS)         < offscreenCaps.getRedBits())        ||
                  (getGLInteger(gl, GL.GL_GREEN_BITS)       < offscreenCaps.getGreenBits())      ||
                  (getGLInteger(gl, GL.GL_BLUE_BITS)        < offscreenCaps.getBlueBits())       ||
                  //                  (getGLInteger(gl, GL.GL_ALPHA_BITS)       < offscreenCaps.getAlphaBits())      ||
                  (getGLInteger(gl, GL.GL_ACCUM_RED_BITS)   < offscreenCaps.getAccumRedBits())   ||
                  (getGLInteger(gl, GL.GL_ACCUM_GREEN_BITS) < offscreenCaps.getAccumGreenBits()) ||
                  (getGLInteger(gl, GL.GL_ACCUM_BLUE_BITS)  < offscreenCaps.getAccumBlueBits())  ||
                  (getGLInteger(gl, GL.GL_ACCUM_ALPHA_BITS) < offscreenCaps.getAccumAlphaBits()) ||
                  //          (getGLInteger(gl, GL.GL_DEPTH_BITS)       < offscreenCaps.getDepthBits())      ||
                  (getGLInteger(gl, GL.GL_STENCIL_BITS)     < offscreenCaps.getStencilBits())) {
                if (DEBUG) {
                  System.err.println("GLJPanel: Falling back to pbuffer-based support because Java2D context insufficient");
                  System.err.println("                    Available              Required");
                  System.err.println("GL_RED_BITS         " + getGLInteger(gl, GL.GL_RED_BITS)         + "              " + offscreenCaps.getRedBits());
                  System.err.println("GL_GREEN_BITS       " + getGLInteger(gl, GL.GL_GREEN_BITS)       + "              " + offscreenCaps.getGreenBits());
                  System.err.println("GL_BLUE_BITS        " + getGLInteger(gl, GL.GL_BLUE_BITS)        + "              " + offscreenCaps.getBlueBits());
                  System.err.println("GL_ALPHA_BITS       " + getGLInteger(gl, GL.GL_ALPHA_BITS)       + "              " + offscreenCaps.getAlphaBits());
                  System.err.println("GL_ACCUM_RED_BITS   " + getGLInteger(gl, GL.GL_ACCUM_RED_BITS)   + "              " + offscreenCaps.getAccumRedBits());
                  System.err.println("GL_ACCUM_GREEN_BITS " + getGLInteger(gl, GL.GL_ACCUM_GREEN_BITS) + "              " + offscreenCaps.getAccumGreenBits());
                  System.err.println("GL_ACCUM_BLUE_BITS  " + getGLInteger(gl, GL.GL_ACCUM_BLUE_BITS)  + "              " + offscreenCaps.getAccumBlueBits());
                  System.err.println("GL_ACCUM_ALPHA_BITS " + getGLInteger(gl, GL.GL_ACCUM_ALPHA_BITS) + "              " + offscreenCaps.getAccumAlphaBits());
                  System.err.println("GL_DEPTH_BITS       " + getGLInteger(gl, GL.GL_DEPTH_BITS)       + "              " + offscreenCaps.getDepthBits());
                  System.err.println("GL_STENCIL_BITS     " + getGLInteger(gl, GL.GL_STENCIL_BITS)     + "              " + offscreenCaps.getStencilBits());
                }
                isInitialized = false;
                shouldInitialize = true;
                oglPipelineEnabled = false;
                handleReshape = true;
                j2dContext.release();
                j2dContext.destroy();
                j2dContext = null;
                return;
              }
              j2dContext.release();
            }

            j2dContext.makeCurrent();
            try {
              captureJ2DState(j2dContext.getGL(), g);
              Object curSurface = Java2D.getOGLSurfaceIdentifier(g);
              if (curSurface != null) {
                if (j2dSurface != curSurface) {
                  if (joglContext != null) {
                    joglContext.destroy();
                    joglContext = null;
                    joglDrawable = null;
                    sendReshape = true;
                    if (DEBUG) {
                      System.err.println("Sending reshape because surface changed");
                      System.err.println("New surface = " + curSurface);
                    }
                  }
                  j2dSurface = curSurface;
                }
                if (joglContext == null) {
                  if (GLDrawableFactory.getFactory().canCreateExternalGLDrawable()) {
                    joglDrawable = GLDrawableFactory.getFactory().createExternalGLDrawable();
                    joglContext = joglDrawable.createContext(shareWith);
                  } else if (GLDrawableFactoryImpl.getFactoryImpl().canCreateContextOnJava2DSurface()) {
                    // Mac OS X code path
                    joglContext = GLDrawableFactoryImpl.getFactoryImpl().createContextOnJava2DSurface(g, shareWith);
                  }
                  if (DEBUG) {
                    joglContext.setGL(new DebugGL(joglContext.getGL()));
                  }

                  if (Java2D.isFBOEnabled() &&
                      Java2D.getOGLSurfaceType(g) == Java2D.FBOBJECT &&
                      fbObjectWorkarounds) {
                    createNewDepthBuffer = true;
                  }
                }
                if (joglContext instanceof Java2DGLContext) {
                  // Mac OS X code path
                  ((Java2DGLContext) joglContext).setGraphics(g);
                }

                if (DEBUG && VERBOSE && Java2D.isFBOEnabled()) {
                  System.err.print("-- Surface type: ");
                  int surfaceType = Java2D.getOGLSurfaceType(g);
                  if (surfaceType == Java2D.UNDEFINED) {
                    System.err.println("UNDEFINED");
                  } else if (surfaceType == Java2D.WINDOW) {
                    System.err.println("WINDOW");
                  } else if (surfaceType == Java2D.PBUFFER) {
                    System.err.println("PBUFFER");
                  } else if (surfaceType == Java2D.TEXTURE) {
                    System.err.println("TEXTURE");
                  } else if (surfaceType == Java2D.FLIP_BACKBUFFER) {
                    System.err.println("FLIP_BACKBUFFER");
                  } else if (surfaceType == Java2D.FBOBJECT) {
                    System.err.println("FBOBJECT");
                  } else {
                    System.err.println("(Unknown surface type " + surfaceType + ")");
                  }
                }

                drawableHelper.invokeGL(joglDrawable, joglContext, displayAction, initAction);
              }
            } finally {
              j2dContext.release();
            }
          }
        });
    } else {
      if (!hardwareAccelerationDisabled) {
        pbuffer.display();
      } else {
        drawableHelper.invokeGL(offscreenDrawable, offscreenContext, displayAction, initAction);
      }

      if (offscreenImage != null) {
        // Draw resulting image in one shot
        g.drawImage(offscreenImage, 0, 0, offscreenImage.getWidth(), offscreenImage.getHeight(), this);
      }
    }
  }

  /** Overridden to track when this component is added to a container.
      Subclasses which override this method must call
      super.addNotify() in their addNotify() method in order to
      function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>addNotify</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void addNotify() {
    super.addNotify();
    shouldInitialize = true;
    if (DEBUG) {
      System.err.println("GLJPanel.addNotify()");
    }
  }

  /** Overridden to track when this component is removed from a
      container. Subclasses which override this method must call
      super.removeNotify() in their removeNotify() method in order to
      function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>removeNotify</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void removeNotify() {
    if (DEBUG) {
      System.err.println("GLJPanel.removeNotify()");
    }
    if (oglPipelineEnabled) {
      Java2D.invokeWithOGLContextCurrent(null, new Runnable() {
          public void run() {
            if (joglContext != null) {
              joglContext.destroy();
              joglContext = null;
            }
            joglDrawable = null;
            if (j2dContext != null) {
              j2dContext.destroy();
              j2dContext = null;
            }
          }
        });
    } else {
      if (!hardwareAccelerationDisabled) {
        if (pbuffer != null) {
          pbuffer.destroy();
          pbuffer = null;
        }
      } else {
        if (offscreenContext != null) {
          offscreenContext.destroy();
          offscreenContext = null;
        }
        if (offscreenDrawable != null) {
          offscreenDrawable.destroy();
          offscreenDrawable = null;
        }
      }
    }
    isInitialized = false;
    super.removeNotify();
  }

  /** Overridden to cause {@link GLDrawableHelper#reshape} to be
      called on all registered {@link GLEventListener}s. Subclasses
      which override this method must call super.reshape() in
      their reshape() method in order to function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>reshape</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void reshape(int x, int y, int width, int height) {
    super.reshape(x, y, width, height);

    reshapeX = x;
    reshapeY = y;
    reshapeWidth = width;
    reshapeHeight = height;
    handleReshape = true;
  }

  public void setOpaque(boolean opaque) {
    if (opaque != isOpaque()) {
      if (offscreenImage != null) {
        offscreenImage.flush();
        offscreenImage = null;
      }
    }
    super.setOpaque(opaque);
  }

  public void addGLEventListener(GLEventListener listener) {
    drawableHelper.addGLEventListener(listener);
  }

  public void removeGLEventListener(GLEventListener listener) {
    drawableHelper.removeGLEventListener(listener);
  }

  public GLContext createContext(GLContext shareWith) {
    if (!hardwareAccelerationDisabled) {
      return pbuffer.createContext(shareWith);
    } else {
      return offscreenDrawable.createContext(shareWith);
    }
  }

  public void setRealized(boolean realized) {
  }

  public GLContext getContext() {
    if (oglPipelineEnabled) {
      return joglContext;
    } else {
      if (!hardwareAccelerationDisabled) {
        // Workaround for crashes in NetBeans GUI builder
        if (pbuffer == null && Beans.isDesignTime()) {
          return null;
        }
        return pbuffer.getContext();
      } else {
        return offscreenContext;
      }
    }
  }

  public GL getGL() {
    GLContext context = getContext();
    return (context == null) ? null : context.getGL();
  }

  public void setGL(GL gl) {
    GLContext context = getContext();
    if (context != null) {
      context.setGL(gl);
    }
  }

  public void setAutoSwapBufferMode(boolean onOrOff) {
    if (!hardwareAccelerationDisabled) {
      // Workaround for crashes in NetBeans GUI builder
      if (pbuffer == null && Beans.isDesignTime()) {
        return;
      }
      pbuffer.setAutoSwapBufferMode(onOrOff);
    } else {
      drawableHelper.setAutoSwapBufferMode(onOrOff);
    }
  }

  public boolean getAutoSwapBufferMode() {
    if (!hardwareAccelerationDisabled) {
      return pbuffer.getAutoSwapBufferMode();
    } else {
      return drawableHelper.getAutoSwapBufferMode();
    }
  }

  public void swapBuffers() {
    if (!hardwareAccelerationDisabled) {
      pbuffer.swapBuffers();
    } else {
      drawableHelper.invokeGL(offscreenDrawable, offscreenContext, swapBuffersAction, initAction);
    }
  }

  /** For a translucent GLJPanel (one for which {@link #setOpaque
      setOpaque}(false) has been called), indicates whether the
      application should preserve the OpenGL color buffer
      (GL_COLOR_BUFFER_BIT) for correct rendering of the GLJPanel and
      underlying widgets which may show through portions of the
      GLJPanel with alpha values less than 1.  Most Swing
      implementations currently expect the GLJPanel to be completely
      cleared (e.g., by <code>glClear(GL_COLOR_BUFFER_BIT |
      GL_DEPTH_BUFFER_BIT)</code>), but for certain optimized Swing
      implementations which use OpenGL internally, it may be possible
      to perform OpenGL rendering using the GLJPanel into the same
      OpenGL drawable as the Swing implementation uses. */
  public boolean shouldPreserveColorBufferIfTranslucent() {
    return oglPipelineEnabled;
  }

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

  private void initialize() {
    if (panelWidth == 0 ||
        panelHeight == 0) {
      // See whether we have a non-zero size yet and can go ahead with
      // initialization
      if (reshapeWidth == 0 ||
          reshapeHeight == 0) {
        return;
      }

      // Pull down reshapeWidth and reshapeHeight into panelWidth and
      // panelHeight eagerly in order to complete initialization, and
      // force a reshape later
      panelWidth = reshapeWidth;
      panelHeight = reshapeHeight;
    }

    if (!oglPipelineEnabled) {
      // Initialize either the hardware-accelerated rendering path or
      // the lightweight rendering path
      if (!hardwareAccelerationDisabled) {
        if (GLDrawableFactory.getFactory().canCreateGLPbuffer()) {
          if (pbuffer != null) {
            throw new InternalError("Creating pbuffer twice without destroying it (memory leak / correctness bug)");
          }
          try {
            pbuffer = GLDrawableFactory.getFactory().createGLPbuffer(offscreenCaps,
                                                                     null,
                                                                     pbufferWidth,
                                                                     pbufferHeight,
                                                                     shareWith);
            updater = new Updater();
            pbuffer.addGLEventListener(updater);
            shouldInitialize = false;
            isInitialized = true;
            return;
          } catch (GLException e) {
            if (DEBUG) {
              e.printStackTrace();
              System.err.println("GLJPanel: Falling back on software rendering because of problems creating pbuffer");
            }
            hardwareAccelerationDisabled = true;
          }
        } else {
          if (DEBUG) {
            System.err.println("GLJPanel: Falling back on software rendering because no pbuffer support");
          }

          // If the factory reports that it can't create a pbuffer,
          // don't try again the next time, and fall through to the
          // software rendering path
          hardwareAccelerationDisabled = true;
        }
      }

      if (softwareRenderingDisabled) {
        throw new GLException("Fallback to software rendering disabled by user");
      }

      // Fall-through path: create an offscreen context instead
      offscreenDrawable = GLDrawableFactoryImpl.getFactoryImpl().createOffscreenDrawable(offscreenCaps, chooser);
      offscreenDrawable.setSize(Math.max(1, panelWidth), Math.max(1, panelHeight));
      offscreenContext = (GLContextImpl) offscreenDrawable.createContext(shareWith);
      offscreenContext.setSynchronized(true);
    }
    updater = new Updater();
    shouldInitialize = false;
    isInitialized = true;
  }

  private void handleReshape() {
    readBackWidthInPixels = 0;
    readBackHeightInPixels = 0;

    panelWidth  = reshapeWidth;
    panelHeight = reshapeHeight;

    if (DEBUG) {
      System.err.println("GLJPanel.handleReshape: (w,h) = (" +
                         panelWidth + "," + panelHeight + ")");
    }

    sendReshape = true;

    if (!oglPipelineEnabled) {
      if (!hardwareAccelerationDisabled) {
        // Use factor larger than 2 during shrinks for some hysteresis
        float shrinkFactor = 2.5f;
        if ((panelWidth > pbufferWidth           )       || (panelHeight > pbufferHeight) ||
            (panelWidth < (pbufferWidth / shrinkFactor)) || (panelHeight < (pbufferWidth / shrinkFactor))) {
          if (DEBUG) {
            System.err.println("Resizing pbuffer from (" + pbufferWidth + ", " + pbufferHeight + ") " +
                               " to fit (" + panelWidth + ", " + panelHeight + ")");
          }
          // Must destroy and recreate pbuffer to fit
          if (pbuffer != null) {
            // Watch for errors during pbuffer destruction (due to
            // buggy / bad OpenGL drivers, in particular SiS) and fall
            // back to software rendering
            try {
              pbuffer.destroy();
            } catch (GLException e) {
              hardwareAccelerationDisabled = true;
              if (DEBUG) {
                System.err.println("WARNING: falling back to software rendering due to bugs in OpenGL drivers");
                e.printStackTrace();
              }
            }
          }
          pbuffer = null;
          isInitialized = false;
          pbufferWidth = getNextPowerOf2(panelWidth);
          pbufferHeight = getNextPowerOf2(panelHeight);
          if (DEBUG && !hardwareAccelerationDisabled) {
            System.err.println("New pbuffer size is (" + pbufferWidth + ", " + pbufferHeight + ")");
          }
          initialize();
        }

        // It looks like NVidia's drivers (at least the ones on my
        // notebook) are buggy and don't allow a rectangle of less than
        // the pbuffer's width to be read...this doesn't really matter
        // because it's the Graphics.drawImage() calls that are the
        // bottleneck. Should probably make the size of the offscreen
        // image be the exact size of the pbuffer to save some work on
        // resize operations...
        if (!hardwareAccelerationDisabled) {
          readBackWidthInPixels  = pbufferWidth;
          readBackHeightInPixels = panelHeight;
        } else {
          // Just disabled hardware acceleration during this resize operation; do a fixup
          readBackWidthInPixels  = Math.max(1, panelWidth);
          readBackHeightInPixels = Math.max(1, panelHeight);
        }
      } else {
        offscreenContext.destroy();
        offscreenDrawable.setSize(Math.max(1, panelWidth), Math.max(1, panelHeight));
        readBackWidthInPixels  = Math.max(1, panelWidth);
        readBackHeightInPixels = Math.max(1, panelHeight);
      }

      if (offscreenImage != null) {
        offscreenImage.flush();
        offscreenImage = null;
      }
    }

    handleReshape = false;
  }

  // FIXME: it isn't clear whether this works any more given that
  // we're accessing the GLDrawable inside of the GLPbuffer directly
  // up in reshape() -- need to rethink and clean this up
  class Updater implements GLEventListener {
    private Graphics g;

    public void setGraphics(Graphics g) {
      this.g = g;
    }

    public void init(GLAutoDrawable drawable) {
      if (oglPipelineEnabled) {
        if (!preGL(g)) {
          return;
        }
      }
      drawableHelper.init(GLJPanel.this);
      if (oglPipelineEnabled) {
        postGL(g);
      }
    }

    public void display(GLAutoDrawable drawable) {
      if (oglPipelineEnabled) {
        if (!preGL(g)) {
          return;
        }
      }

      if (sendReshape) {
        if (DEBUG) {
          System.err.println("glViewport(" + viewportX + ", " + viewportY + ", " + panelWidth + ", " + panelHeight + ")");
        }
        getGL().glViewport(viewportX, viewportY, panelWidth, panelHeight);
        drawableHelper.reshape(GLJPanel.this, viewportX, viewportY, panelWidth, panelHeight);
        sendReshape = false;
      }

      drawableHelper.display(GLJPanel.this);

      if (!oglPipelineEnabled) {
        // Must now copy pixels from offscreen context into surface
        if (offscreenImage == null) {
          if (panelWidth > 0 && panelHeight > 0) {
            // It looks like NVidia's drivers (at least the ones on my
            // notebook) are buggy and don't allow a sub-rectangle to be
            // read from a pbuffer...this doesn't really matter because
            // it's the Graphics.drawImage() calls that are the
            // bottleneck

            int awtFormat = 0;
            int hwGLFormat = 0;
            if (!hardwareAccelerationDisabled) {
              // This seems to be a good choice on all platforms
              hwGLFormat = GL.GL_UNSIGNED_INT_8_8_8_8_REV;
            }

            // Should be more flexible in these BufferedImage formats;
            // perhaps see what the preferred image types are on the
            // given platform
            if (isOpaque()) {
              awtFormat = BufferedImage.TYPE_INT_RGB;
            } else {
              awtFormat = BufferedImage.TYPE_INT_ARGB;
            }

            offscreenImage = new BufferedImage(panelWidth,
                                               panelHeight,
                                               awtFormat);
            switch (awtFormat) {
            case BufferedImage.TYPE_3BYTE_BGR:
              glFormat = GL.GL_BGR;
              glType   = GL.GL_UNSIGNED_BYTE;
              readBackBytes = ByteBuffer.allocate(readBackWidthInPixels * readBackHeightInPixels * 3);
              break;

            case BufferedImage.TYPE_INT_RGB:
            case BufferedImage.TYPE_INT_ARGB:
              glFormat = GL.GL_BGRA;
              glType   = (hardwareAccelerationDisabled
                          ? offscreenContext.getOffscreenContextPixelDataType()
                          : hwGLFormat);
              readBackInts = IntBuffer.allocate(readBackWidthInPixels * readBackHeightInPixels);
              break;

            default:
              // FIXME: Support more off-screen image types (current
              // offscreen context implementations don't use others, and
              // some of the OpenGL formats aren't supported in the 1.1
              // headers, which we're currently using)
              throw new GLException("Unsupported offscreen image type " + awtFormat);
            }
          }
        }

        if (offscreenImage != null) {
          GL gl = getGL();
          // Save current modes
          gl.glGetIntegerv(GL.GL_PACK_SWAP_BYTES,    swapbytes, 0);
          gl.glGetIntegerv(GL.GL_PACK_ROW_LENGTH,    rowlength, 0);
          gl.glGetIntegerv(GL.GL_PACK_SKIP_ROWS,     skiprows, 0);
          gl.glGetIntegerv(GL.GL_PACK_SKIP_PIXELS,   skippixels, 0);
          gl.glGetIntegerv(GL.GL_PACK_ALIGNMENT,     alignment, 0);

          gl.glPixelStorei(GL.GL_PACK_SWAP_BYTES,    GL.GL_FALSE);
          gl.glPixelStorei(GL.GL_PACK_ROW_LENGTH,    readBackWidthInPixels);
          gl.glPixelStorei(GL.GL_PACK_SKIP_ROWS,     0);
          gl.glPixelStorei(GL.GL_PACK_SKIP_PIXELS,   0);
          gl.glPixelStorei(GL.GL_PACK_ALIGNMENT,     1);

          // Actually read the pixels.
          gl.glReadBuffer(GL.GL_FRONT);
          if (readBackBytes != null) {
            gl.glReadPixels(0, 0, readBackWidthInPixels, readBackHeightInPixels, glFormat, glType, readBackBytes);
          } else if (readBackInts != null) {
            gl.glReadPixels(0, 0, readBackWidthInPixels, readBackHeightInPixels, glFormat, glType, readBackInts);
          }

          // Restore saved modes.
          gl.glPixelStorei(GL.GL_PACK_SWAP_BYTES,  swapbytes[0]);
          gl.glPixelStorei(GL.GL_PACK_ROW_LENGTH,  rowlength[0]);
          gl.glPixelStorei(GL.GL_PACK_SKIP_ROWS,   skiprows[0]);
          gl.glPixelStorei(GL.GL_PACK_SKIP_PIXELS, skippixels[0]);
          gl.glPixelStorei(GL.GL_PACK_ALIGNMENT,   alignment[0]);

          if (readBackBytes != null || readBackInts != null) {
            // Copy temporary data into raster of BufferedImage for faster
            // blitting Note that we could avoid this copy in the cases
            // where !offscreenContext.offscreenImageNeedsVerticalFlip(),
            // but that's the software rendering path which is very slow
            // anyway
            Object src  = null;
            Object dest = null;
            int    srcIncr  = 0;
            int    destIncr = 0;

            if (readBackBytes != null) {
              src = readBackBytes.array();
              dest = ((DataBufferByte) offscreenImage.getRaster().getDataBuffer()).getData();
              srcIncr = readBackWidthInPixels * 3;
              destIncr = offscreenImage.getWidth() * 3;
            } else {
              src = readBackInts.array();
              dest = ((DataBufferInt) offscreenImage.getRaster().getDataBuffer()).getData();
              srcIncr = readBackWidthInPixels;
              destIncr = offscreenImage.getWidth();
            }

            if (!hardwareAccelerationDisabled ||
                offscreenContext.offscreenImageNeedsVerticalFlip()) {
              int srcPos = 0;
              int destPos = (offscreenImage.getHeight() - 1) * destIncr;
              for (; destPos >= 0; srcPos += srcIncr, destPos -= destIncr) {
                System.arraycopy(src, srcPos, dest, destPos, destIncr);
              }
            } else {
              int srcPos = 0;
              int destEnd = destIncr * offscreenImage.getHeight();
              for (int destPos = 0; destPos < destEnd; srcPos += srcIncr, destPos += destIncr) {
                System.arraycopy(src, srcPos, dest, destPos, destIncr);
              }
            }

	    // Note: image will be drawn back in paintComponent() for
	    // correctness on all platforms
          }
        }
      } else {
        // Cause OpenGL pipeline to flush its results because
        // otherwise it's possible we will buffer up multiple frames'
        // rendering results, resulting in apparent mouse lag
        GL gl = getGL();
        gl.glFinish();

        postGL(g);
      }
    }

    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
      // This is handled above and dispatched directly to the appropriate context
    }

    public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
    }
  }

  class InitAction implements Runnable {
    public void run() {
      updater.init(GLJPanel.this);
    }
  }
  private InitAction initAction = new InitAction();

  class DisplayAction implements Runnable {
    public void run() {
      updater.display(GLJPanel.this);
    }
  }
  private DisplayAction displayAction = new DisplayAction();

  // This one is used exclusively in the non-hardware-accelerated case
  class SwapBuffersAction implements Runnable {
    public void run() {
      offscreenDrawable.swapBuffers();
    }
  }
  private SwapBuffersAction swapBuffersAction = new SwapBuffersAction();

  class PaintImmediatelyAction implements Runnable {
    public void run() {
      paintImmediately(0, 0, getWidth(), getHeight());
    }
  }
  private PaintImmediatelyAction paintImmediatelyAction = new PaintImmediatelyAction();

  private int getNextPowerOf2(int number) {
    // Workaround for problems where 0 width or height are transiently
    // seen during layout
    if (number == 0) {
      return 2;
    }

    if (((number-1) & number) == 0) {
      //ex: 8 -> 0b1000; 8-1=7 -> 0b0111; 0b1000&0b0111 == 0
      return number;
    }
    int power = 0;
    while (number > 0) {
      number = number>>1;
      power++;
    }
    return (1<<power);
  }

  private int getGLInteger(GL gl, int which) {
    int[] tmp = new int[1];
    gl.glGetIntegerv(which, tmp, 0);
    return tmp[0];
  }
}