-
-
Notifications
You must be signed in to change notification settings - Fork 215
Expand file tree
/
Copy pathsrc_engineWebGL.js.html
More file actions
891 lines (784 loc) · 53.6 KB
/
src_engineWebGL.js.html
File metadata and controls
891 lines (784 loc) · 53.6 KB
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
<!DOCTYPE html><html lang="en" style="font-size:16px"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><link rel="icon" href="./static/favicon.png"><meta name="description" content="LittleJS is a lightweight HTML5 game engine with fast WebGL rendering, physics, particles, sound, and more!"><meta name="keywords" content="javascript, game engine, html5, webgl, 2d, game development, indie games"><meta name="author" content="Frank Force"><meta property="og:title" content="LittleJS - The Tiny JavaScript Game Engine"><meta property="og:description" content="Lightweight HTML5 game engine with WebGL rendering, physics, and sound"><meta property="og:type" content="website"><title>Source: src/engineWebGL.js</title><!--[if lt IE 9]>
<script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
<![endif]--><script src="scripts/third-party/hljs.js" defer="defer"></script><script src="scripts/third-party/hljs-line-num.js" defer="defer"></script><script src="scripts/third-party/popper.js" defer="defer"></script><script src="scripts/third-party/tippy.js" defer="defer"></script><script src="scripts/third-party/tocbot.min.js"></script><script>var baseURL="/",locationPathname="";baseURL=(baseURL=(baseURL="https://killedbyapixel.github.io/LittleJS/docs/").replace(/https?:\/\//i,"")).substr(baseURL.indexOf("/"))</script><link rel="stylesheet" href="styles/clean-jsdoc-theme.min.css"><svg aria-hidden="true" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" style="display:none"><defs><symbol id="copy-icon" viewbox="0 0 488.3 488.3"><g><path d="M314.25,85.4h-227c-21.3,0-38.6,17.3-38.6,38.6v325.7c0,21.3,17.3,38.6,38.6,38.6h227c21.3,0,38.6-17.3,38.6-38.6V124 C352.75,102.7,335.45,85.4,314.25,85.4z M325.75,449.6c0,6.4-5.2,11.6-11.6,11.6h-227c-6.4,0-11.6-5.2-11.6-11.6V124 c0-6.4,5.2-11.6,11.6-11.6h227c6.4,0,11.6,5.2,11.6,11.6V449.6z"/><path d="M401.05,0h-227c-21.3,0-38.6,17.3-38.6,38.6c0,7.5,6,13.5,13.5,13.5s13.5-6,13.5-13.5c0-6.4,5.2-11.6,11.6-11.6h227 c6.4,0,11.6,5.2,11.6,11.6v325.7c0,6.4-5.2,11.6-11.6,11.6c-7.5,0-13.5,6-13.5,13.5s6,13.5,13.5,13.5c21.3,0,38.6-17.3,38.6-38.6 V38.6C439.65,17.3,422.35,0,401.05,0z"/></g></symbol><symbol id="search-icon" viewBox="0 0 512 512"><g><g><path d="M225.474,0C101.151,0,0,101.151,0,225.474c0,124.33,101.151,225.474,225.474,225.474 c124.33,0,225.474-101.144,225.474-225.474C450.948,101.151,349.804,0,225.474,0z M225.474,409.323 c-101.373,0-183.848-82.475-183.848-183.848S124.101,41.626,225.474,41.626s183.848,82.475,183.848,183.848 S326.847,409.323,225.474,409.323z"/></g></g><g><g><path d="M505.902,476.472L386.574,357.144c-8.131-8.131-21.299-8.131-29.43,0c-8.131,8.124-8.131,21.306,0,29.43l119.328,119.328 c4.065,4.065,9.387,6.098,14.715,6.098c5.321,0,10.649-2.033,14.715-6.098C514.033,497.778,514.033,484.596,505.902,476.472z"/></g></g></symbol><symbol id="font-size-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M11.246 15H4.754l-2 5H.6L7 4h2l6.4 16h-2.154l-2-5zm-.8-2L8 6.885 5.554 13h4.892zM21 12.535V12h2v8h-2v-.535a4 4 0 1 1 0-6.93zM19 18a2 2 0 1 0 0-4 2 2 0 0 0 0 4z"/></symbol><symbol id="add-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M11 11V5h2v6h6v2h-6v6h-2v-6H5v-2z"/></symbol><symbol id="minus-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M5 11h14v2H5z"/></symbol><symbol id="dark-theme-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M10 7a7 7 0 0 0 12 4.9v.1c0 5.523-4.477 10-10 10S2 17.523 2 12 6.477 2 12 2h.1A6.979 6.979 0 0 0 10 7zm-6 5a8 8 0 0 0 15.062 3.762A9 9 0 0 1 8.238 4.938 7.999 7.999 0 0 0 4 12z"/></symbol><symbol id="light-theme-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M12 18a6 6 0 1 1 0-12 6 6 0 0 1 0 12zm0-2a4 4 0 1 0 0-8 4 4 0 0 0 0 8zM11 1h2v3h-2V1zm0 19h2v3h-2v-3zM3.515 4.929l1.414-1.414L7.05 5.636 5.636 7.05 3.515 4.93zM16.95 18.364l1.414-1.414 2.121 2.121-1.414 1.414-2.121-2.121zm2.121-14.85l1.414 1.415-2.121 2.121-1.414-1.414 2.121-2.121zM5.636 16.95l1.414 1.414-2.121 2.121-1.414-1.414 2.121-2.121zM23 11v2h-3v-2h3zM4 11v2H1v-2h3z"/></symbol><symbol id="reset-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M18.537 19.567A9.961 9.961 0 0 1 12 22C6.477 22 2 17.523 2 12S6.477 2 12 2s10 4.477 10 10c0 2.136-.67 4.116-1.81 5.74L17 12h3a8 8 0 1 0-2.46 5.772l.997 1.795z"/></symbol><symbol id="down-icon" viewBox="0 0 16 16"><path fill-rule="evenodd" clip-rule="evenodd" d="M12.7803 6.21967C13.0732 6.51256 13.0732 6.98744 12.7803 7.28033L8.53033 11.5303C8.23744 11.8232 7.76256 11.8232 7.46967 11.5303L3.21967 7.28033C2.92678 6.98744 2.92678 6.51256 3.21967 6.21967C3.51256 5.92678 3.98744 5.92678 4.28033 6.21967L8 9.93934L11.7197 6.21967C12.0126 5.92678 12.4874 5.92678 12.7803 6.21967Z"></path></symbol><symbol id="codepen-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M16.5 13.202L13 15.535v3.596L19.197 15 16.5 13.202zM14.697 12L12 10.202 9.303 12 12 13.798 14.697 12zM20 10.869L18.303 12 20 13.131V10.87zM19.197 9L13 4.869v3.596l3.5 2.333L19.197 9zM7.5 10.798L11 8.465V4.869L4.803 9 7.5 10.798zM4.803 15L11 19.131v-3.596l-3.5-2.333L4.803 15zM4 13.131L5.697 12 4 10.869v2.262zM2 9a1 1 0 0 1 .445-.832l9-6a1 1 0 0 1 1.11 0l9 6A1 1 0 0 1 22 9v6a1 1 0 0 1-.445.832l-9 6a1 1 0 0 1-1.11 0l-9-6A1 1 0 0 1 2 15V9z"/></symbol><symbol id="close-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M12 10.586l4.95-4.95 1.414 1.414-4.95 4.95 4.95 4.95-1.414 1.414-4.95-4.95-4.95 4.95-1.414-1.414 4.95-4.95-4.95-4.95L7.05 5.636z"/></symbol><symbol id="menu-icon" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0z"/><path d="M3 4h18v2H3V4zm0 7h18v2H3v-2zm0 7h18v2H3v-2z"/></symbol></defs></svg></head><body data-theme="dark"><div class="sidebar-container"><div class="sidebar" id="sidebar"><a href="/" class="sidebar-title sidebar-title-anchor">LittleJS - The Tiny JavaScript Game Engine That Can!</a><div class="sidebar-items-container"><div class="sidebar-section-title with-arrow" data-isopen="false" id="sidebar-classes"><div>Classes</div><svg><use xlink:href="#down-icon"></use></svg></div><div class="sidebar-section-children-container"><div class="sidebar-section-children"><a href="Audio.Sound.html">Sound</a></div><div class="sidebar-section-children"><a href="Audio.SoundInstance.html">SoundInstance</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dDistanceJoint.html">Box2dDistanceJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dFrictionJoint.html">Box2dFrictionJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dGearJoint.html">Box2dGearJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dJoint.html">Box2dJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dKinematicObject.html">Box2dKinematicObject</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dMotorJoint.html">Box2dMotorJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dObject.html">Box2dObject</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPinJoint.html">Box2dPinJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPlugin.html">Box2dPlugin</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPrismaticJoint.html">Box2dPrismaticJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPulleyJoint.html">Box2dPulleyJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dRevoluteJoint.html">Box2dRevoluteJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dRopeJoint.html">Box2dRopeJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dStaticObject.html">Box2dStaticObject</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dTargetJoint.html">Box2dTargetJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dTileLayer.html">Box2dTileLayer</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dWeldJoint.html">Box2dWeldJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dWheelJoint.html">Box2dWheelJoint</a></div><div class="sidebar-section-children"><a href="Box2dRaycastResult.html">Box2dRaycastResult</a></div><div class="sidebar-section-children"><a href="Draw.FontImage.html">FontImage</a></div><div class="sidebar-section-children"><a href="Draw.TextureInfo.html">TextureInfo</a></div><div class="sidebar-section-children"><a href="Draw.TileInfo.html">TileInfo</a></div><div class="sidebar-section-children"><a href="Engine.Color.html">Color</a></div><div class="sidebar-section-children"><a href="Engine.EngineObject.html">EngineObject</a></div><div class="sidebar-section-children"><a href="Engine.RandomGenerator.html">RandomGenerator</a></div><div class="sidebar-section-children"><a href="Engine.Timer.html">Timer</a></div><div class="sidebar-section-children"><a href="Engine.Vector2.html">Vector2</a></div><div class="sidebar-section-children"><a href="Medals.Medal.html">Medal</a></div><div class="sidebar-section-children"><a href="Newgrounds.NewgroundsMedal.html">NewgroundsMedal</a></div><div class="sidebar-section-children"><a href="Newgrounds.NewgroundsPlugin.html">NewgroundsPlugin</a></div><div class="sidebar-section-children"><a href="Particles.Particle.html">Particle</a></div><div class="sidebar-section-children"><a href="Particles.ParticleEmitter.html">ParticleEmitter</a></div><div class="sidebar-section-children"><a href="PostProcess.PostProcessPlugin.html">PostProcessPlugin</a></div><div class="sidebar-section-children"><a href="TileLayers.CanvasLayer.html">CanvasLayer</a></div><div class="sidebar-section-children"><a href="TileLayers.TileCollisionLayer.html">TileCollisionLayer</a></div><div class="sidebar-section-children"><a href="TileLayers.TileLayer.html">TileLayer</a></div><div class="sidebar-section-children"><a href="TileLayers.TileLayerData.html">TileLayerData</a></div><div class="sidebar-section-children"><a href="UISystem.UIButton.html">UIButton</a></div><div class="sidebar-section-children"><a href="UISystem.UICheckbox.html">UICheckbox</a></div><div class="sidebar-section-children"><a href="UISystem.UIObject.html">UIObject</a></div><div class="sidebar-section-children"><a href="UISystem.UIScrollbar.html">UIScrollbar</a></div><div class="sidebar-section-children"><a href="UISystem.UISystemPlugin.html">UISystemPlugin</a></div><div class="sidebar-section-children"><a href="UISystem.UIText.html">UIText</a></div><div class="sidebar-section-children"><a href="UISystem.UITile.html">UITile</a></div><div class="sidebar-section-children"><a href="UISystem.UIVideo.html">UIVideo</a></div><div class="sidebar-section-children"><a href="ZzFXM.ZzFXMusic.html">ZzFXMusic</a></div></div><div class="sidebar-section-title with-arrow" data-isopen="false" id="sidebar-namespaces"><div>Namespaces</div><svg><use xlink:href="#down-icon"></use></svg></div><div class="sidebar-section-children-container"><div class="sidebar-section-children"><a href="Audio.html">Audio</a></div><div class="sidebar-section-children"><a href="Box2D.html">Box2D</a></div><div class="sidebar-section-children"><a href="Debug.html">Debug</a></div><div class="sidebar-section-children"><a href="Draw.html">Draw</a></div><div class="sidebar-section-children"><a href="DrawUtilities.html">DrawUtilities</a></div><div class="sidebar-section-children"><a href="Engine.html">Engine</a></div><div class="sidebar-section-children"><a href="Input.html">Input</a></div><div class="sidebar-section-children"><a href="Math.html">Math</a></div><div class="sidebar-section-children"><a href="Medals.html">Medals</a></div><div class="sidebar-section-children"><a href="Newgrounds.html">Newgrounds</a></div><div class="sidebar-section-children"><a href="Particles.html">Particles</a></div><div class="sidebar-section-children"><a href="PostProcess.html">PostProcess</a></div><div class="sidebar-section-children"><a href="Random.html">Random</a></div><div class="sidebar-section-children"><a href="Settings.html">Settings</a></div><div class="sidebar-section-children"><a href="TileLayers.html">TileLayers</a></div><div class="sidebar-section-children"><a href="UISystem.html">UISystem</a></div><div class="sidebar-section-children"><a href="Utilities.html">Utilities</a></div><div class="sidebar-section-children"><a href="WebGL.html">WebGL</a></div><div class="sidebar-section-children"><a href="ZzFXM.html">ZzFXM</a></div></div></div></div></div><div class="navbar-container" id="VuAckcnZhf"><nav class="navbar"><div class="navbar-left-items"><div class="navbar-item"><a id="" href="https://github.com/KilledByAPixel/LittleJS" target="_blank">GitHub</a></div><div class="navbar-item"><a id="" href="https://killedbyapixel.github.io/LittleJS/examples/" target="_blank">Examples</a></div><div class="navbar-item"><a id="" href="https://github.com/KilledByAPixel/LittleJS/blob/main/FAQ.md" target="_blank">FAQ</a></div></div><div class="navbar-right-items"><div class="navbar-right-item"><button class="icon-button search-button" aria-label="open-search"><svg><use xlink:href="#search-icon"></use></svg></button></div><div class="navbar-right-item"><button class="icon-button theme-toggle" aria-label="toggle-theme"><svg><use class="theme-svg-use" xlink:href="#light-theme-icon"></use></svg></button></div><div class="navbar-right-item"><button class="icon-button font-size" aria-label="change-font-size"><svg><use xlink:href="#font-size-icon"></use></svg></button></div></div><nav></nav></nav></div><div class="toc-container"><div class="toc-content"><span class="bold">On this page</span><div id="eed4d2a0bfd64539bb9df78095dec881"></div></div></div><div class="body-wrapper"><div class="main-content"><div class="main-wrapper"><section id="source-page" class="source-page"><header><h1 id="title" class="has-anchor">src_engineWebGL.js</h1></header><article><pre class="prettyprint source lang-js"><code>/**
* LittleJS WebGL Interface
* - WebGL2 rendering engine for high-performance graphics
* - Batched sprite rendering for drawing thousands of sprites efficiently
* - Instanced rendering using vertex array objects (VAOs)
* - Polygon rendering with triangle strip support
* - Shader system with custom vertex and fragment shaders
* - Texture management with automatic atlas support
* - Post-processing effects via framebuffer and shader plugins
* - Automatic fallback to Canvas2D if WebGL is unavailable
* - Context loss and restoration handling
* - Can be disabled with glEnable setting
* - Advanced users can create custom shaders and render targets
* @namespace WebGL
*/
'use strict';
/** The WebGL canvas which appears below the main canvas
* @type {HTMLCanvasElement}
* @memberof WebGL */
let glCanvas;
/** WebGL2 context for `glCanvas`
* @type {WebGL2RenderingContext}
* @memberof WebGL */
let glContext;
/** Should WebGL be setup with anti-aliasing? must be set before calling engineInit
* @type {boolean}
* @memberof WebGL */
let glAntialias = true;
// WebGL internal variables not exposed to documentation
let glShader, glPolyShader, glPolyMode, glAdditive, glBatchAdditive, glActiveTexture, glArrayBuffer, glGeometryBuffer, glPositionData, glColorData, glBatchCount, glTextureInfos, glInstancedVAO, glPolyVAO, glFramebuffer, glRenderTarget, glCanBeEnabled = true;
// WebGL internal constants
const gl_ARRAY_BUFFER_SIZE = 5e5;
const gl_INDICES_PER_INSTANCE = 11;
const gl_INSTANCE_BYTE_STRIDE = gl_INDICES_PER_INSTANCE * 4;
const gl_MAX_INSTANCES = gl_ARRAY_BUFFER_SIZE / gl_INSTANCE_BYTE_STRIDE | 0;
const gl_INDICES_PER_POLY_VERTEX = 3;
const gl_POLY_VERTEX_BYTE_STRIDE = gl_INDICES_PER_POLY_VERTEX * 4;
const gl_MAX_POLY_VERTEXES = gl_ARRAY_BUFFER_SIZE / gl_POLY_VERTEX_BYTE_STRIDE | 0;
///////////////////////////////////////////////////////////////////////////////
// Initialize WebGL, called automatically by the engine
function glInit(rootElement)
{
// keep set of texture infos so they can be restored if context is lost
glTextureInfos = new Set;
if (!glEnable || headlessMode)
{
glCanBeEnabled = false;
return;
}
// create the canvas and textures
glCanvas = document.createElement('canvas');
glContext = glCanvas.getContext('webgl2', {antialias:glAntialias});
if (!glContext)
{
console.warn('WebGL2 not supported, falling back to 2D canvas rendering!');
glCanvas = glContext = undefined;
glEnable = false;
glCanBeEnabled = false;
return;
}
// attach the WebGL canvas;
rootElement.appendChild(glCanvas);
// startup webgl
initWebGL();
// setup context lost and restore handlers
glCanvas.addEventListener('webglcontextlost', (e)=>
{
glEnable = false; // disable WebGL rendering
glCanvas.style.display = 'none'; // hide the gl canvas
e.preventDefault(); // prevent default to allow restoration
LOG('WebGL context lost! Switching to Canvas2d rendering.');
// remove WebGL textures
for (const info of glTextureInfos)
info.glTexture = undefined;
glActiveTexture = undefined;
pluginList.forEach(plugin=>plugin.glContextLost?.());
});
glCanvas.addEventListener('webglcontextrestored', ()=>
{
glEnable = true; // re-enable WebGL rendering
glCanvas.style.display = ''; // show the gl canvas
LOG('WebGL context restored, reinitializing...');
// reinit WebGL and restore textures
initWebGL();
for (const info of glTextureInfos)
info.glTexture = glCreateTexture(info.image);
pluginList.forEach(plugin=>plugin.glContextRestored?.());
});
function initWebGL()
{
// setup instanced rendering shader program
glShader = glCreateProgram(
'#version 300 es\n' + // specify GLSL ES version
'precision highp float;'+ // use highp for accuracy
'uniform mat4 m;'+ // transform matrix
'in vec2 g;'+ // in: geometry
'in vec4 p,u,c,a;'+ // in: position/size, uvs, color, additiveColor
'in float r;'+ // in: rotation
'out vec2 v;'+ // out: uv
'out vec4 d,e;'+ // out: color, additiveColor
'void main(){'+ // shader entry point
'vec2 s=(g-.5)*p.zw;'+ // get size offset
'gl_Position=m*vec4(p.xy+s*cos(r)-vec2(-s.y,s)*sin(r),1,1);'+ // transform position
'v=mix(u.xw,u.zy,g);'+ // pass uv to fragment shader
'd=c;e=a;'+ // pass colors to fragment shader
'}' // end of shader
,
'#version 300 es\n' + // specify GLSL ES version
'precision highp float;'+ // use highp for accuracy
'uniform sampler2D s;'+ // texture
'in vec2 v;'+ // in: uv
'in vec4 d,e;'+ // in: color, additiveColor
'out vec4 c;'+ // out: color
'void main(){'+ // shader entry point
'c=texture(s,v)*d+e;'+ // modulate texture by color plus additive
'}' // end of shader
);
// setup poly rendering shaders
glPolyShader = glCreateProgram(
'#version 300 es\n' + // specify GLSL ES version
'precision highp float;'+ // use highp for better accuracy
'uniform mat4 m;'+ // transform matrix
'in vec2 p;'+ // in: position
'in vec4 c;'+ // in: color
'out vec4 d;'+ // out: color
'void main(){'+ // shader entry point
'gl_Position=m*vec4(p,1,1);'+ // transform position
'd=c;'+ // pass color to fragment shader
'}' // end of shader
,
'#version 300 es\n' + // specify GLSL ES version
'precision highp float;'+ // use highp for better accuracy
'in vec4 d;'+ // in: color
'out vec4 c;'+ // out: color
'void main(){'+ // shader entry point
'c=d;'+ // set color
'}' // end of shader
);
// init buffers
const glInstanceData = new ArrayBuffer(gl_ARRAY_BUFFER_SIZE);
glPositionData = new Float32Array(glInstanceData);
glColorData = new Uint32Array(glInstanceData);
glArrayBuffer = glContext.createBuffer();
glGeometryBuffer = glContext.createBuffer();
glFramebuffer = glContext.createFramebuffer();
glBatchCount = 0;
// create the geometry buffer, triangle strip square
const geometry = new Float32Array([0,0,1,0,0,1,1,1]);
glContext.bindBuffer(glContext.ARRAY_BUFFER, glGeometryBuffer);
glContext.bufferData(glContext.ARRAY_BUFFER, geometry, glContext.STATIC_DRAW);
let offset, shader, stride;
const initVertexAttrib = (name, type, typeSize, size, divisor=0)=>
{
const location = glContext.getAttribLocation(shader, name);
const normalize = typeSize === 1;
const fixedStride = typeSize && stride;
glContext.enableVertexAttribArray(location);
glContext.vertexAttribPointer(location, size, type, normalize, fixedStride, offset);
glContext.vertexAttribDivisor(location, divisor);
offset += size*typeSize;
}
// setup VAO for instanced rendering
glInstancedVAO = glContext.createVertexArray();
glContext.bindVertexArray(glInstancedVAO);
// configure instanced vertex attributes
offset = 0, shader = glShader, stride = gl_INSTANCE_BYTE_STRIDE;
glContext.bindBuffer(glContext.ARRAY_BUFFER, glGeometryBuffer);
initVertexAttrib('g', glContext.FLOAT, 0, 2); // geometry
glContext.bindBuffer(glContext.ARRAY_BUFFER, glArrayBuffer);
glContext.bufferData(glContext.ARRAY_BUFFER, gl_ARRAY_BUFFER_SIZE, glContext.DYNAMIC_DRAW);
initVertexAttrib('p', glContext.FLOAT, 4, 4, 1); // position & size
initVertexAttrib('u', glContext.FLOAT, 4, 4, 1); // texture coords
initVertexAttrib('c', glContext.UNSIGNED_BYTE, 1, 4, 1); // color
initVertexAttrib('a', glContext.UNSIGNED_BYTE, 1, 4, 1); // additiveColor
initVertexAttrib('r', glContext.FLOAT, 4, 1, 1); // rotation
// setup VAO for poly rendering
glPolyVAO = glContext.createVertexArray();
glContext.bindVertexArray(glPolyVAO);
// configure poly vertex attributes
offset = 0, shader = glPolyShader, stride = gl_POLY_VERTEX_BYTE_STRIDE;
initVertexAttrib('p', glContext.FLOAT, 4, 2); // position
initVertexAttrib('c', glContext.UNSIGNED_BYTE, 1, 4); // color
}
}
function glSetInstancedMode(force=false)
{
if (!force && !glPolyMode) return;
// setup instanced mode
glFlush();
glPolyMode = false;
glContext.useProgram(glShader);
glContext.bindVertexArray(glInstancedVAO);
}
function glSetPolyMode()
{
if (glPolyMode) return;
// setup poly mode
glFlush();
glPolyMode = true;
glContext.useProgram(glPolyShader);
glContext.bindVertexArray(glPolyVAO);
}
// Setup WebGL render each frame, called automatically by engine
// Also used by tile layer rendering when redrawing tiles
function glPreRender(clear=true)
{
if (!glEnable || !glContext) return;
ASSERT(!glBatchCount, 'glPreRender called with unflushed batch.');
if (!glRenderTarget)
{
// set to same size as main canvas
glCanvas.width = mainCanvasSize.x;
glCanvas.height = mainCanvasSize.y;
}
glContext.viewport(0, 0, mainCanvasSize.x, mainCanvasSize.y);
clear && glClearCanvas();
// build the transform matrix
const s = vec2(2*cameraScale).divide(mainCanvasSize);
if (glRenderTarget)
s.y = -s.y; // invert y when using render target
const rotatedCam = cameraPos.rotate(-cameraAngle);
const p = vec2(-1).subtract(rotatedCam.multiply(s));
const ca = cos(cameraAngle);
const sa = sin(cameraAngle);
const transform = [
s.x * ca, s.y * sa, 0, 0,
-s.x * sa, s.y * ca, 0, 0,
1, 1, 1, 0,
p.x, p.y, 0, 1];
// set the same transform matrix for both shaders
const initUniform = (program, uniform, value)=>
{
glContext.useProgram(program);
const location = glContext.getUniformLocation(program, uniform);
glContext.uniformMatrix4fv(location, false, value);
}
initUniform(glPolyShader, 'm', transform);
initUniform(glShader, 'm', transform);
// set the active texture
glContext.activeTexture(glContext.TEXTURE0);
if (textureInfos[0])
{
glActiveTexture = textureInfos[0].glTexture;
glContext.bindTexture(glContext.TEXTURE_2D, glActiveTexture);
}
// rebind the array buffer
glContext.bindBuffer(glContext.ARRAY_BUFFER, glArrayBuffer);
// start with additive blending off
glAdditive = glBatchAdditive = false;
// force it to set instanced mode
glSetInstancedMode(true);
}
/** Clear the canvas and setup the viewport
* @memberof WebGL */
function glClearCanvas()
{
if (!glContext) return;
// clear using the canvasClearColor
const color = canvasClearColor;
glContext.clearColor(color.r, color.g, color.b, color.a);
glContext.clear(glContext.COLOR_BUFFER_BIT);
}
/** Set the WebGL texture, called automatically if using multiple textures
* - This may also flush the gl buffer resulting in more draw calls and worse performance
* @param {WebGLTexture} texture
* @param {boolean} [wrap] - Should the texture wrap or clamp
* @memberof WebGL */
function glSetTexture(texture, wrap=false)
{
// must flush cache with the old texture to set a new one
if (!glContext || texture === glActiveTexture) return;
glFlush();
glActiveTexture = texture;
glContext.bindTexture(glContext.TEXTURE_2D, glActiveTexture);
// set wrap mode
const wrapMode = wrap ? glContext.REPEAT : glContext.CLAMP_TO_EDGE;
glContext.texParameteri(glContext.TEXTURE_2D, glContext.TEXTURE_WRAP_S, wrapMode);
glContext.texParameteri(glContext.TEXTURE_2D, glContext.TEXTURE_WRAP_T, wrapMode);
}
/** Compile WebGL shader of the given type, will throw errors if in debug mode
* @param {string} source
* @param {number} type
* @return {WebGLShader}
* @memberof WebGL */
function glCompileShader(source, type)
{
if (!glContext) return;
// build the shader
const shader = glContext.createShader(type);
glContext.shaderSource(shader, source);
glContext.compileShader(shader);
// check for errors
if (debug && !glContext.getShaderParameter(shader, glContext.COMPILE_STATUS))
throw glContext.getShaderInfoLog(shader);
return shader;
}
/** Create WebGL program with given shaders
* @param {string} vsSource
* @param {string} fsSource
* @return {WebGLProgram}
* @memberof WebGL */
function glCreateProgram(vsSource, fsSource)
{
if (!glContext) return;
// build the program
const program = glContext.createProgram();
glContext.attachShader(program, glCompileShader(vsSource, glContext.VERTEX_SHADER));
glContext.attachShader(program, glCompileShader(fsSource, glContext.FRAGMENT_SHADER));
glContext.linkProgram(program);
// check for errors
if (debug && !glContext.getProgramParameter(program, glContext.LINK_STATUS))
throw glContext.getProgramInfoLog(program);
return program;
}
/** Create WebGL texture from an image and init the texture settings
* Restores the active texture when done
* @param {HTMLImageElement|HTMLCanvasElement|OffscreenCanvas} [image]
* @return {WebGLTexture}
* @memberof WebGL */
function glCreateTexture(image)
{
if (!glContext) return;
// build the texture
const texture = glContext.createTexture();
let mipMap = false;
if (image?.width)
{
glSetTextureData(texture, image);
glContext.bindTexture(glContext.TEXTURE_2D, texture);
mipMap = !tilesPixelated && isPowerOfTwo(image.width) && isPowerOfTwo(image.height);
}
else
{
// create a white texture
const whitePixel = new Uint8Array([255, 255, 255, 255]);
glContext.bindTexture(glContext.TEXTURE_2D, texture);
glContext.texImage2D(glContext.TEXTURE_2D, 0, glContext.RGBA, 1, 1, 0, glContext.RGBA, glContext.UNSIGNED_BYTE, whitePixel);
}
// set texture filtering
const magFilter = tilesPixelated ? glContext.NEAREST : glContext.LINEAR;
const minFilter = mipMap ? glContext.LINEAR_MIPMAP_LINEAR : magFilter;
glContext.texParameteri(glContext.TEXTURE_2D, glContext.TEXTURE_MAG_FILTER, magFilter);
glContext.texParameteri(glContext.TEXTURE_2D, glContext.TEXTURE_MIN_FILTER, minFilter);
if (mipMap)
glContext.generateMipmap(glContext.TEXTURE_2D);
// rebind active texture
glContext.bindTexture(glContext.TEXTURE_2D, glActiveTexture);
return texture;
}
/** Deletes a WebGL texture
* @param {WebGLTexture} [texture]
* @memberof WebGL */
function glDeleteTexture(texture)
{
if (!glContext) return;
glContext.deleteTexture(texture);
}
/** Set WebGL texture data from an image, restores the active texture when done
* @param {WebGLTexture} texture
* @param {HTMLImageElement|HTMLCanvasElement|OffscreenCanvas} image
* @memberof WebGL */
function glSetTextureData(texture, image)
{
if (!glContext) return;
// build the texture
ASSERT(image?.width > 0, 'Invalid image data.');
glContext.bindTexture(glContext.TEXTURE_2D, texture);
glContext.texImage2D(glContext.TEXTURE_2D, 0, glContext.RGBA, glContext.RGBA, glContext.UNSIGNED_BYTE, image);
// rebind active texture
glContext.bindTexture(glContext.TEXTURE_2D, glActiveTexture);
}
/** Tells WebGL to create or update the glTexture and start tracking it
* @param {TextureInfo} textureInfo
* @memberof WebGL */
function glRegisterTextureInfo(textureInfo)
{
if (headlessMode) return;
// add texture info to tracking list even if gl is not enabled
glTextureInfos.add(textureInfo);
if (!glContext) return;
// create or set the texture data
if (textureInfo.glTexture)
glSetTextureData(textureInfo.glTexture, textureInfo.image);
else
textureInfo.glTexture = glCreateTexture(textureInfo.image);
}
/** Tells WebGL to destroy the glTexture and stop tracking it
* @param {TextureInfo} textureInfo
* @memberof WebGL */
function glUnregisterTextureInfo(textureInfo)
{
if (headlessMode) return;
// delete texture info from tracking list even if gl is not enabled
glTextureInfos.delete(textureInfo);
// unset and destroy the texture
const glTexture = textureInfo.glTexture;
textureInfo.glTexture = undefined;
glDeleteTexture(glTexture);
}
/** Draw all sprites and clear out the buffer, called automatically by the system whenever necessary
* @memberof WebGL */
function glFlush()
{
if (glEnable && glContext && glBatchCount)
{
// set bend mode
const destBlend = glBatchAdditive ? glContext.ONE : glContext.ONE_MINUS_SRC_ALPHA;
glContext.blendFuncSeparate(glContext.SRC_ALPHA, destBlend, glContext.ONE, destBlend);
glContext.enable(glContext.BLEND);
const byteLength = glBatchCount *
(glPolyMode ? gl_INDICES_PER_POLY_VERTEX : gl_INDICES_PER_INSTANCE);
glContext.bufferSubData(glContext.ARRAY_BUFFER, 0, glPositionData, 0, byteLength);
// draw the batch
if (glPolyMode)
glContext.drawArrays(glContext.TRIANGLE_STRIP, 0, glBatchCount);
else
glContext.drawArraysInstanced(glContext.TRIANGLE_STRIP, 0, 4, glBatchCount);
drawCount += glBatchCount;
glBatchCount = 0;
}
glBatchAdditive = glAdditive;
}
/** Flush any sprites still in the buffer and copy to main canvas
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} context
* @memberof WebGL */
function glCopyToContext(context)
{
if (!glEnable || !glContext) return;
glFlush();
context.drawImage(glCanvas, 0, 0);
}
/** Set anti-aliasing for WebGL canvas
* Must be called before engineInit
* @param {boolean} [antialias]
* @memberof WebGL */
function glSetAntialias(antialias=true)
{
ASSERT(!glCanvas, 'must be called before engineInit');
glAntialias = antialias;
}
/** Add a sprite to the gl draw list, used by all gl draw functions
* @param {number} x
* @param {number} y
* @param {number} sizeX
* @param {number} sizeY
* @param {number} [angle]
* @param {number} [uv0X]
* @param {number} [uv0Y]
* @param {number} [uv1X]
* @param {number} [uv1Y]
* @param {number} [rgba=-1] - white is -1
* @param {number} [rgbaAdditive=0] - black is 0
* @memberof WebGL */
function glDraw(x, y, sizeX, sizeY, angle=0, uv0X=0, uv0Y=0, uv1X=1, uv1Y=1, rgba=-1, rgbaAdditive=0)
{
// flush if there is not enough room or if different blend mode
if (glBatchCount >= gl_MAX_INSTANCES || glBatchAdditive !== glAdditive)
glFlush();
glSetInstancedMode();
let offset = glBatchCount++ * gl_INDICES_PER_INSTANCE;
glPositionData[offset++] = x;
glPositionData[offset++] = y;
glPositionData[offset++] = sizeX;
glPositionData[offset++] = sizeY;
glPositionData[offset++] = uv0X;
glPositionData[offset++] = uv0Y;
glPositionData[offset++] = uv1X;
glPositionData[offset++] = uv1Y;
glColorData[offset++] = rgba;
glColorData[offset++] = rgbaAdditive;
glPositionData[offset++] = angle;
}
/** Transform and add a polygon to the gl draw list
* @param {Array<Vector2>} points - Array of Vector2 points
* @param {number} rgba - Color of the polygon as a 32-bit integer
* @param {number} x
* @param {number} y
* @param {number} sx
* @param {number} sy
* @param {number} angle
* @param {boolean} [tristrip] - should tristrip algorithm be used
* @memberof WebGL */
function glDrawPointsTransform(points, rgba, x, y, sx, sy, angle, tristrip=true)
{
const pointsOut = [];
for (const p of points)
{
// transform the point
const px = p.x*sx;
const py = p.y*sy;
const sa = sin(-angle);
const ca = cos(-angle);
pointsOut.push(vec2(x + ca*px - sa*py, y + sa*px + ca*py));
}
const drawPoints = tristrip ? glPolyStrip(pointsOut) : pointsOut;
glDrawPoints(drawPoints, rgba);
}
/** Transform and add a polygon to the gl draw list
* @param {Array<Vector2>} points - Array of Vector2 points
* @param {number} rgba - Color of the polygon as a 32-bit integer
* @param {number} lineWidth - Width of the outline
* @param {number} x
* @param {number} y
* @param {number} sx
* @param {number} sy
* @param {number} angle
* @param {boolean} [wrap] - Should the outline connect the first and last points
* @memberof WebGL */
function glDrawOutlineTransform(points, rgba, lineWidth, x, y, sx, sy, angle, wrap=true)
{
const outlinePoints = glMakeOutline(points, lineWidth, wrap);
glDrawPointsTransform(outlinePoints, rgba, x, y, sx, sy, angle, false);
}
/** Add a list of points to the gl draw list
* @param {Array<Vector2>} points - Array of Vector2 points in tri strip order
* @param {number} rgba - Color as a 32-bit integer
* @memberof WebGL */
function glDrawPoints(points, rgba)
{
if (!glEnable || points.length < 3)
return; // needs at least 3 points to have area
// flush if there is not enough room or if different blend mode
const vertCount = points.length + 2;
if (glBatchCount+vertCount >= gl_MAX_POLY_VERTEXES || glBatchAdditive !== glAdditive)
glFlush();
glSetPolyMode();
// setup triangle strip with degenerate verts at start and end
let offset = glBatchCount * gl_INDICES_PER_POLY_VERTEX;
for (let i = vertCount; i--;)
{
const j = clamp(i-1, 0, vertCount-3);
const point = points[j];
glPositionData[offset++] = point.x;
glPositionData[offset++] = point.y;
glColorData[offset++] = rgba;
}
glBatchCount += vertCount;
}
/** Add a list of colored points to the gl draw list
* @param {Array<Vector2>} points - Array of Vector2 points in tri strip order
* @param {Array<number>} pointColors - Array of 32-bit integer colors
* @memberof WebGL */
function glDrawColoredPoints(points, pointColors)
{
if (!glEnable || points.length < 3)
return; // needs at least 3 points to have area
// flush if there is not enough room or if different blend mode
const vertCount = points.length + 2;
if (glBatchCount+vertCount >= gl_MAX_POLY_VERTEXES || glBatchAdditive !== glAdditive)
glFlush();
glSetPolyMode();
// setup triangle strip with degenerate verts at start and end
let offset = glBatchCount * gl_INDICES_PER_POLY_VERTEX;
for (let i = vertCount; i--;)
{
const j = clamp(i-1, 0, vertCount-3);
const point = points[j];
const color = pointColors[j];
glPositionData[offset++] = point.x;
glPositionData[offset++] = point.y;
glColorData[offset++] = color;
}
glBatchCount += vertCount;
}
/** Set the WebGL render target to the given texture or back to the canvas
* @param {WebGLTexture} [texture] - a texture or undefined to use normal glCanvas
* @param {boolean} [clear] - should the render target be cleared
* @memberof WebGL */
function glSetRenderTarget(texture, clear=false)
{
if (texture)
{
glRenderTarget = texture;
glContext.bindFramebuffer(glContext.FRAMEBUFFER, glFramebuffer);
glContext.framebufferTexture2D(glContext.FRAMEBUFFER,
glContext.COLOR_ATTACHMENT0, glContext.TEXTURE_2D, texture, 0);
glPreRender(clear);
}
else
{
glFlush();
glRenderTarget = undefined;
glContext.bindFramebuffer(glContext.FRAMEBUFFER, null);
}
}
/** Clear out a rectangle area of the WebGL canvas or render target
* @param {number} x
* @param {number} y
* @param {number} width
* @param {number} height
* @memberof WebGL */
function glClearRect(x, y, width, height)
{
if (!glEnable) return;
// Enable scissor test to clear only the specified area
glContext.enable(glContext.SCISSOR_TEST);
glContext.scissor(x, y, width, height);
glContext.clearColor(0, 0, 0, 0);
glContext.clear(glContext.COLOR_BUFFER_BIT);
glContext.disable(glContext.SCISSOR_TEST);
}
///////////////////////////////////////////////////////////////////////////////
// WebGL internal function to convert polygon to outline triangle strip
function glMakeOutline(points, width, wrap=true)
{
if (points.length < 2)
return [];
const halfWidth = width / 2;
const strip = [];
const n = points.length;
const e = 1e-6;
const miterLimit = width*100;
for (let i = 0; i < n; i++)
{
// for each vertex, calculate normal based on adjacent edges
const prev = points[wrap ? (i - 1 + n) % n : max(i - 1, 0)];
const curr = points[i];
const next = points[wrap ? (i + 1) % n : min(i + 1, n - 1)];
// direction from previous to current
const dx1 = curr.x - prev.x;
const dy1 = curr.y - prev.y;
const len1 = (dx1*dx1 + dy1*dy1)**.5;
// direction from current to next
const dx2 = next.x - curr.x;
const dy2 = next.y - curr.y;
const len2 = (dx2*dx2 + dy2*dy2)**.5;
if (len1 < e && len2 < e)
continue; // skip degenerate point
// calculate perpendicular normals for each edge
const nx1 = len1 > e ? -dy1 / len1 : 0;
const ny1 = len1 > e ? dx1 / len1 : 0;
const nx2 = len2 > e ? -dy2 / len2 : 0;
const ny2 = len2 > e ? dx2 / len2 : 0;
// average the normals for miter
let nx = nx1 + nx2;
let ny = ny1 + ny2;
const nlen = (nx*nx + ny*ny)**.5;
if (nlen < e)
{
// 180 degree turn - use perpendicular
nx = nx1;
ny = ny1;
}
else
{
// calculate miter length
nx /= nlen;
ny /= nlen;
const dot = nx1 * nx + ny1 * ny;
if (dot > e)
{
// scale normal by miter length, clamped to miterLimit
const miterLength = min(1 / dot, miterLimit);
nx *= miterLength;
ny *= miterLength;
}
}
// create inner and outer points along the normal
const inner = vec2(curr.x - nx * halfWidth, curr.y - ny * halfWidth);
const outer = vec2(curr.x + nx * halfWidth, curr.y + ny * halfWidth);
strip.push(inner);
strip.push(outer);
}
if (strip.length > 1 && wrap)
{
// close the loop
strip.push(strip[0]);
strip.push(strip[1]);
}
return strip;
}
// WebGL internal function to convert polys to tri strips
function glPolyStrip(points)
{
// validate input
if (points.length < 3)
return [];
// cross product helper: (b-a) x (c-a)
const cross = (a,b,c)=> (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
// calculate signed area of polygon
const signedArea = (poly)=>
{
let area = 0;
for (let i = poly.length; i--;)
{
const j = (i+1) % poly.length;
area += poly[i].cross(poly[j]);
}
return area;
}
// ensure counter-clockwise winding
if (signedArea(points) < 0)
points = points.reverse();
// check if point is inside triangle
const e = 1e-9;
const pointInTriangle = (p, a, b, c)=>
{
const c1 = cross(a, b, p);
const c2 = cross(b, c, p);
const c3 = cross(c, a, p);
const negative = (c1<-e?1:0) + (c2<-e?1:0) + (c3<-e?1:0);
const positive = (c1> e?1:0) + (c2> e?1:0) + (c3> e?1:0);
return !(negative && positive);
};
// ear clipping triangulation
const indices = [];
for (let i = 0; i < points.length; ++i)
indices[i] = i;
const triangles = [];
let attempts = 0;
const maxAttempts = points.length ** 2 + 100;
while (indices.length > 3 && attempts++ < maxAttempts)
{
let foundEar = false;
for (let i = 0; i < indices.length; i++)
{
const i0 = indices[(i + indices.length - 1) % indices.length];
const i1 = indices[i];
const i2 = indices[(i + 1) % indices.length];
const a = points[i0], b = points[i1], c = points[i2];
// check if convex
if (cross(a, b, c) < e) continue;
// check if any other point is inside
let hasInside = false;
for (let j = 0; j < indices.length; j++)
{
const k = indices[j];
if (k === i0 || k === i1 || k === i2) continue;
const p = points[k];
hasInside = pointInTriangle(p, a, b, c);
if (hasInside) break;
}
if (hasInside) continue;
// found valid ear
triangles.push([i0, i1, i2]);
indices.splice(i, 1);
foundEar = true;
break;
}
// fallback for degenerate cases
if (!foundEar)
{
let worstIndex = -1, worstValue = Infinity;
for (let i = 0; i < indices.length; i++)
{
const i0 = indices[(i + indices.length - 1) % indices.length];
const i1 = indices[i];
const i2 = indices[(i + 1) % indices.length];
const value = abs(cross(points[i0], points[i1], points[i2]));
if (value < worstValue)
{
worstValue = value;
worstIndex = i;
}
}
if (worstIndex < 0) break;
const i0 = indices[(worstIndex + indices.length - 1) % indices.length];
const i1 = indices[worstIndex];
const i2 = indices[(worstIndex + 1) % indices.length];
triangles.push([i0, i1, i2]);
indices.splice(worstIndex, 1);
}
}
// add final triangle
if (indices.length === 3)
triangles.push([indices[0], indices[1], indices[2]]);
if (!triangles.length)
return [];
// convert triangles to triangle strip with degenerate connectors
const strip = [];
let [a0, b0, c0] = triangles[0];
strip.push(points[a0], points[b0], points[c0]);
for (let i = 1; i < triangles.length; i++)
{
// add degenerate bridge from last vertex to first of new triangle
const [a, b, c] = triangles[i];
strip.push(points[c0], points[a]);
strip.push(points[a], points[b], points[c]);
c0 = c;
}
return strip;
}</code></pre></article></section><footer class="footer" id="PeOAagUepe"><div class="wrapper"><a href="https://github.com/KilledByAPixel/LittleJS">LittleJS - MIT License - Copyright 2021 Frank Force</a></div></footer></div></div></div><div class="search-container" id="PkfLWpAbet" style="display:none"><div class="wrapper" id="iCxFxjkHbP"><button class="icon-button search-close-button" id="VjLlGakifb" aria-label="close search"><svg><use xlink:href="#close-icon"></use></svg></button><div class="search-box-c"><svg><use xlink:href="#search-icon"></use></svg> <input type="text" id="vpcKVYIppa" class="search-input" placeholder="Search..." autofocus></div><div class="search-result-c" id="fWwVHRuDuN"><span class="search-result-c-text">Type anything to view search result</span></div></div></div><div class="mobile-menu-icon-container"><button class="icon-button" id="mobile-menu" data-isopen="false" aria-label="menu"><svg><use xlink:href="#menu-icon"></use></svg></button></div><div id="mobile-sidebar" class="mobile-sidebar-container"><div class="mobile-sidebar-wrapper"><a href="/" class="sidebar-title sidebar-title-anchor">LittleJS - The Tiny JavaScript Game Engine That Can!</a><div class="mobile-nav-links"><div class="navbar-item"><a id="" href="https://github.com/KilledByAPixel/LittleJS" target="_blank">GitHub</a></div><div class="navbar-item"><a id="" href="https://killedbyapixel.github.io/LittleJS/examples/" target="_blank">Examples</a></div><div class="navbar-item"><a id="" href="https://github.com/KilledByAPixel/LittleJS/blob/main/FAQ.md" target="_blank">FAQ</a></div></div><div class="mobile-sidebar-items-c"><div class="sidebar-section-title with-arrow" data-isopen="false" id="sidebar-classes"><div>Classes</div><svg><use xlink:href="#down-icon"></use></svg></div><div class="sidebar-section-children-container"><div class="sidebar-section-children"><a href="Audio.Sound.html">Sound</a></div><div class="sidebar-section-children"><a href="Audio.SoundInstance.html">SoundInstance</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dDistanceJoint.html">Box2dDistanceJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dFrictionJoint.html">Box2dFrictionJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dGearJoint.html">Box2dGearJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dJoint.html">Box2dJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dKinematicObject.html">Box2dKinematicObject</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dMotorJoint.html">Box2dMotorJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dObject.html">Box2dObject</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPinJoint.html">Box2dPinJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPlugin.html">Box2dPlugin</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPrismaticJoint.html">Box2dPrismaticJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dPulleyJoint.html">Box2dPulleyJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dRevoluteJoint.html">Box2dRevoluteJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dRopeJoint.html">Box2dRopeJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dStaticObject.html">Box2dStaticObject</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dTargetJoint.html">Box2dTargetJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dTileLayer.html">Box2dTileLayer</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dWeldJoint.html">Box2dWeldJoint</a></div><div class="sidebar-section-children"><a href="Box2D.Box2dWheelJoint.html">Box2dWheelJoint</a></div><div class="sidebar-section-children"><a href="Box2dRaycastResult.html">Box2dRaycastResult</a></div><div class="sidebar-section-children"><a href="Draw.FontImage.html">FontImage</a></div><div class="sidebar-section-children"><a href="Draw.TextureInfo.html">TextureInfo</a></div><div class="sidebar-section-children"><a href="Draw.TileInfo.html">TileInfo</a></div><div class="sidebar-section-children"><a href="Engine.Color.html">Color</a></div><div class="sidebar-section-children"><a href="Engine.EngineObject.html">EngineObject</a></div><div class="sidebar-section-children"><a href="Engine.RandomGenerator.html">RandomGenerator</a></div><div class="sidebar-section-children"><a href="Engine.Timer.html">Timer</a></div><div class="sidebar-section-children"><a href="Engine.Vector2.html">Vector2</a></div><div class="sidebar-section-children"><a href="Medals.Medal.html">Medal</a></div><div class="sidebar-section-children"><a href="Newgrounds.NewgroundsMedal.html">NewgroundsMedal</a></div><div class="sidebar-section-children"><a href="Newgrounds.NewgroundsPlugin.html">NewgroundsPlugin</a></div><div class="sidebar-section-children"><a href="Particles.Particle.html">Particle</a></div><div class="sidebar-section-children"><a href="Particles.ParticleEmitter.html">ParticleEmitter</a></div><div class="sidebar-section-children"><a href="PostProcess.PostProcessPlugin.html">PostProcessPlugin</a></div><div class="sidebar-section-children"><a href="TileLayers.CanvasLayer.html">CanvasLayer</a></div><div class="sidebar-section-children"><a href="TileLayers.TileCollisionLayer.html">TileCollisionLayer</a></div><div class="sidebar-section-children"><a href="TileLayers.TileLayer.html">TileLayer</a></div><div class="sidebar-section-children"><a href="TileLayers.TileLayerData.html">TileLayerData</a></div><div class="sidebar-section-children"><a href="UISystem.UIButton.html">UIButton</a></div><div class="sidebar-section-children"><a href="UISystem.UICheckbox.html">UICheckbox</a></div><div class="sidebar-section-children"><a href="UISystem.UIObject.html">UIObject</a></div><div class="sidebar-section-children"><a href="UISystem.UIScrollbar.html">UIScrollbar</a></div><div class="sidebar-section-children"><a href="UISystem.UISystemPlugin.html">UISystemPlugin</a></div><div class="sidebar-section-children"><a href="UISystem.UIText.html">UIText</a></div><div class="sidebar-section-children"><a href="UISystem.UITile.html">UITile</a></div><div class="sidebar-section-children"><a href="UISystem.UIVideo.html">UIVideo</a></div><div class="sidebar-section-children"><a href="ZzFXM.ZzFXMusic.html">ZzFXMusic</a></div></div><div class="sidebar-section-title with-arrow" data-isopen="false" id="sidebar-namespaces"><div>Namespaces</div><svg><use xlink:href="#down-icon"></use></svg></div><div class="sidebar-section-children-container"><div class="sidebar-section-children"><a href="Audio.html">Audio</a></div><div class="sidebar-section-children"><a href="Box2D.html">Box2D</a></div><div class="sidebar-section-children"><a href="Debug.html">Debug</a></div><div class="sidebar-section-children"><a href="Draw.html">Draw</a></div><div class="sidebar-section-children"><a href="DrawUtilities.html">DrawUtilities</a></div><div class="sidebar-section-children"><a href="Engine.html">Engine</a></div><div class="sidebar-section-children"><a href="Input.html">Input</a></div><div class="sidebar-section-children"><a href="Math.html">Math</a></div><div class="sidebar-section-children"><a href="Medals.html">Medals</a></div><div class="sidebar-section-children"><a href="Newgrounds.html">Newgrounds</a></div><div class="sidebar-section-children"><a href="Particles.html">Particles</a></div><div class="sidebar-section-children"><a href="PostProcess.html">PostProcess</a></div><div class="sidebar-section-children"><a href="Random.html">Random</a></div><div class="sidebar-section-children"><a href="Settings.html">Settings</a></div><div class="sidebar-section-children"><a href="TileLayers.html">TileLayers</a></div><div class="sidebar-section-children"><a href="UISystem.html">UISystem</a></div><div class="sidebar-section-children"><a href="Utilities.html">Utilities</a></div><div class="sidebar-section-children"><a href="WebGL.html">WebGL</a></div><div class="sidebar-section-children"><a href="ZzFXM.html">ZzFXM</a></div></div></div><div class="mobile-navbar-actions"><div class="navbar-right-item"><button class="icon-button search-button" aria-label="open-search"><svg><use xlink:href="#search-icon"></use></svg></button></div><div class="navbar-right-item"><button class="icon-button theme-toggle" aria-label="toggle-theme"><svg><use class="theme-svg-use" xlink:href="#light-theme-icon"></use></svg></button></div><div class="navbar-right-item"><button class="icon-button font-size" aria-label="change-font-size"><svg><use xlink:href="#font-size-icon"></use></svg></button></div></div></div></div><script type="text/javascript" src="scripts/core.min.js"></script><script src="scripts/search.min.js" defer="defer"></script><script src="scripts/third-party/fuse.js" defer="defer"></script><script type="text/javascript">var tocbotInstance=tocbot.init({tocSelector:"#eed4d2a0bfd64539bb9df78095dec881",contentSelector:".main-content",headingSelector:"h1, h2, h3",hasInnerContainers:!0,scrollContainer:".main-content",headingsOffset:130,onClick:bringLinkToView})</script></body></html>