/
HeightmapTerrainData.js
903 lines (831 loc) · 29.2 KB
/
HeightmapTerrainData.js
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
import when from "../ThirdParty/when.js";
import BoundingSphere from "./BoundingSphere.js";
import Cartesian3 from "./Cartesian3.js";
import defaultValue from "./defaultValue.js";
import defined from "./defined.js";
import DeveloperError from "./DeveloperError.js";
import GeographicProjection from "./GeographicProjection.js";
import HeightmapEncoding from "./HeightmapEncoding.js";
import HeightmapTessellator from "./HeightmapTessellator.js";
import CesiumMath from "./Math.js";
import OrientedBoundingBox from "./OrientedBoundingBox.js";
import Rectangle from "./Rectangle.js";
import TaskProcessor from "./TaskProcessor.js";
import TerrainEncoding from "./TerrainEncoding.js";
import TerrainMesh from "./TerrainMesh.js";
import TerrainProvider from "./TerrainProvider.js";
/**
* Terrain data for a single tile where the terrain data is represented as a heightmap. A heightmap
* is a rectangular array of heights in row-major order from north to south and west to east.
*
* @alias HeightmapTerrainData
* @constructor
*
* @param {Object} options Object with the following properties:
* @param {Int8Array|Uint8Array|Int16Array|Uint16Array|Int32Array|Uint32Array|Float32Array|Float64Array} options.buffer The buffer containing height data.
* @param {Number} options.width The width (longitude direction) of the heightmap, in samples.
* @param {Number} options.height The height (latitude direction) of the heightmap, in samples.
* @param {Number} [options.childTileMask=15] A bit mask indicating which of this tile's four children exist.
* If a child's bit is set, geometry will be requested for that tile as well when it
* is needed. If the bit is cleared, the child tile is not requested and geometry is
* instead upsampled from the parent. The bit values are as follows:
* <table>
* <tr><th>Bit Position</th><th>Bit Value</th><th>Child Tile</th></tr>
* <tr><td>0</td><td>1</td><td>Southwest</td></tr>
* <tr><td>1</td><td>2</td><td>Southeast</td></tr>
* <tr><td>2</td><td>4</td><td>Northwest</td></tr>
* <tr><td>3</td><td>8</td><td>Northeast</td></tr>
* </table>
* @param {Uint8Array} [options.waterMask] The water mask included in this terrain data, if any. A water mask is a square
* Uint8Array or image where a value of 255 indicates water and a value of 0 indicates land.
* Values in between 0 and 255 are allowed as well to smoothly blend between land and water.
* @param {Object} [options.structure] An object describing the structure of the height data.
* @param {Number} [options.structure.heightScale=1.0] The factor by which to multiply height samples in order to obtain
* the height above the heightOffset, in meters. The heightOffset is added to the resulting
* height after multiplying by the scale.
* @param {Number} [options.structure.heightOffset=0.0] The offset to add to the scaled height to obtain the final
* height in meters. The offset is added after the height sample is multiplied by the
* heightScale.
* @param {Number} [options.structure.elementsPerHeight=1] The number of elements in the buffer that make up a single height
* sample. This is usually 1, indicating that each element is a separate height sample. If
* it is greater than 1, that number of elements together form the height sample, which is
* computed according to the structure.elementMultiplier and structure.isBigEndian properties.
* @param {Number} [options.structure.stride=1] The number of elements to skip to get from the first element of
* one height to the first element of the next height.
* @param {Number} [options.structure.elementMultiplier=256.0] The multiplier used to compute the height value when the
* stride property is greater than 1. For example, if the stride is 4 and the strideMultiplier
* is 256, the height is computed as follows:
* `height = buffer[index] + buffer[index + 1] * 256 + buffer[index + 2] * 256 * 256 + buffer[index + 3] * 256 * 256 * 256`
* This is assuming that the isBigEndian property is false. If it is true, the order of the
* elements is reversed.
* @param {Boolean} [options.structure.isBigEndian=false] Indicates endianness of the elements in the buffer when the
* stride property is greater than 1. If this property is false, the first element is the
* low-order element. If it is true, the first element is the high-order element.
* @param {Number} [options.structure.lowestEncodedHeight] The lowest value that can be stored in the height buffer. Any heights that are lower
* than this value after encoding with the `heightScale` and `heightOffset` are clamped to this value. For example, if the height
* buffer is a `Uint16Array`, this value should be 0 because a `Uint16Array` cannot store negative numbers. If this parameter is
* not specified, no minimum value is enforced.
* @param {Number} [options.structure.highestEncodedHeight] The highest value that can be stored in the height buffer. Any heights that are higher
* than this value after encoding with the `heightScale` and `heightOffset` are clamped to this value. For example, if the height
* buffer is a `Uint16Array`, this value should be `256 * 256 - 1` or 65535 because a `Uint16Array` cannot store numbers larger
* than 65535. If this parameter is not specified, no maximum value is enforced.
* @param {HeightmapEncoding} [options.encoding=HeightmapEncoding.NONE] The encoding that is used on the buffer.
* @param {Boolean} [options.createdByUpsampling=false] True if this instance was created by upsampling another instance;
* otherwise, false.
*
*
* @example
* var buffer = ...
* var heightBuffer = new Uint16Array(buffer, 0, that._heightmapWidth * that._heightmapWidth);
* var childTileMask = new Uint8Array(buffer, heightBuffer.byteLength, 1)[0];
* var waterMask = new Uint8Array(buffer, heightBuffer.byteLength + 1, buffer.byteLength - heightBuffer.byteLength - 1);
* var terrainData = new Cesium.HeightmapTerrainData({
* buffer : heightBuffer,
* width : 65,
* height : 65,
* childTileMask : childTileMask,
* waterMask : waterMask
* });
*
* @see TerrainData
* @see QuantizedMeshTerrainData
* @see GoogleEarthEnterpriseTerrainData
*/
function HeightmapTerrainData(options) {
//>>includeStart('debug', pragmas.debug);
if (!defined(options) || !defined(options.buffer)) {
throw new DeveloperError("options.buffer is required.");
}
if (!defined(options.width)) {
throw new DeveloperError("options.width is required.");
}
if (!defined(options.height)) {
throw new DeveloperError("options.height is required.");
}
//>>includeEnd('debug');
this._buffer = options.buffer;
this._width = options.width;
this._height = options.height;
this._childTileMask = defaultValue(options.childTileMask, 15);
this._encoding = defaultValue(options.encoding, HeightmapEncoding.NONE);
var defaultStructure = HeightmapTessellator.DEFAULT_STRUCTURE;
var structure = options.structure;
if (!defined(structure)) {
structure = defaultStructure;
} else if (structure !== defaultStructure) {
structure.heightScale = defaultValue(
structure.heightScale,
defaultStructure.heightScale
);
structure.heightOffset = defaultValue(
structure.heightOffset,
defaultStructure.heightOffset
);
structure.elementsPerHeight = defaultValue(
structure.elementsPerHeight,
defaultStructure.elementsPerHeight
);
structure.stride = defaultValue(structure.stride, defaultStructure.stride);
structure.elementMultiplier = defaultValue(
structure.elementMultiplier,
defaultStructure.elementMultiplier
);
structure.isBigEndian = defaultValue(
structure.isBigEndian,
defaultStructure.isBigEndian
);
}
this._structure = structure;
this._createdByUpsampling = defaultValue(options.createdByUpsampling, false);
this._waterMask = options.waterMask;
this._skirtHeight = undefined;
this._bufferType =
this._encoding === HeightmapEncoding.LERC
? Float32Array
: this._buffer.constructor;
this._mesh = undefined;
}
Object.defineProperties(HeightmapTerrainData.prototype, {
/**
* An array of credits for this tile.
* @memberof HeightmapTerrainData.prototype
* @type {Credit[]}
*/
credits: {
get: function () {
return undefined;
},
},
/**
* The water mask included in this terrain data, if any. A water mask is a square
* Uint8Array or image where a value of 255 indicates water and a value of 0 indicates land.
* Values in between 0 and 255 are allowed as well to smoothly blend between land and water.
* @memberof HeightmapTerrainData.prototype
* @type {Uint8Array|HTMLImageElement|HTMLCanvasElement}
*/
waterMask: {
get: function () {
return this._waterMask;
},
},
childTileMask: {
get: function () {
return this._childTileMask;
},
},
});
var taskProcessor = new TaskProcessor("createVerticesFromHeightmap");
/**
* Creates a {@link TerrainMesh} from this terrain data.
*
* @private
*
* @param {TilingScheme} tilingScheme The tiling scheme to which this tile belongs.
* @param {Number} x The X coordinate of the tile for which to create the terrain data.
* @param {Number} y The Y coordinate of the tile for which to create the terrain data.
* @param {Number} level The level of the tile for which to create the terrain data.
* @param {Number} [exaggeration=1.0] The scale used to exaggerate the terrain.
* @returns {Promise.<TerrainMesh>|undefined} A promise for the terrain mesh, or undefined if too many
* asynchronous mesh creations are already in progress and the operation should
* be retried later.
*/
HeightmapTerrainData.prototype.createMesh = function (
tilingScheme,
x,
y,
level,
exaggeration
) {
//>>includeStart('debug', pragmas.debug);
if (!defined(tilingScheme)) {
throw new DeveloperError("tilingScheme is required.");
}
if (!defined(x)) {
throw new DeveloperError("x is required.");
}
if (!defined(y)) {
throw new DeveloperError("y is required.");
}
if (!defined(level)) {
throw new DeveloperError("level is required.");
}
//>>includeEnd('debug');
var ellipsoid = tilingScheme.ellipsoid;
var nativeRectangle = tilingScheme.tileXYToNativeRectangle(x, y, level);
var rectangle = tilingScheme.tileXYToRectangle(x, y, level);
exaggeration = defaultValue(exaggeration, 1.0);
// Compute the center of the tile for RTC rendering.
var center = ellipsoid.cartographicToCartesian(Rectangle.center(rectangle));
var structure = this._structure;
var levelZeroMaxError = TerrainProvider.getEstimatedLevelZeroGeometricErrorForAHeightmap(
ellipsoid,
this._width,
tilingScheme.getNumberOfXTilesAtLevel(0)
);
var thisLevelMaxError = levelZeroMaxError / (1 << level);
this._skirtHeight = Math.min(thisLevelMaxError * 4.0, 1000.0);
var verticesPromise = taskProcessor.scheduleTask({
heightmap: this._buffer,
structure: structure,
includeWebMercatorT: true,
width: this._width,
height: this._height,
nativeRectangle: nativeRectangle,
rectangle: rectangle,
relativeToCenter: center,
ellipsoid: ellipsoid,
skirtHeight: this._skirtHeight,
isGeographic: tilingScheme.projection instanceof GeographicProjection,
exaggeration: exaggeration,
encoding: this._encoding,
});
if (!defined(verticesPromise)) {
// Postponed
return undefined;
}
var that = this;
return when(verticesPromise, function (result) {
var indicesAndEdges;
if (that._skirtHeight > 0.0) {
indicesAndEdges = TerrainProvider.getRegularGridAndSkirtIndicesAndEdgeIndices(
result.gridWidth,
result.gridHeight
);
} else {
indicesAndEdges = TerrainProvider.getRegularGridIndicesAndEdgeIndices(
result.gridWidth,
result.gridHeight
);
}
var vertexCountWithoutSkirts = result.gridWidth * result.gridHeight;
// Clone complex result objects because the transfer from the web worker
// has stripped them down to JSON-style objects.
that._mesh = new TerrainMesh(
center,
new Float32Array(result.vertices),
indicesAndEdges.indices,
indicesAndEdges.indexCountWithoutSkirts,
vertexCountWithoutSkirts,
result.minimumHeight,
result.maximumHeight,
BoundingSphere.clone(result.boundingSphere3D),
Cartesian3.clone(result.occludeePointInScaledSpace),
result.numberOfAttributes,
OrientedBoundingBox.clone(result.orientedBoundingBox),
TerrainEncoding.clone(result.encoding),
exaggeration,
indicesAndEdges.westIndicesSouthToNorth,
indicesAndEdges.southIndicesEastToWest,
indicesAndEdges.eastIndicesNorthToSouth,
indicesAndEdges.northIndicesWestToEast
);
// Free memory received from server after mesh is created.
that._buffer = undefined;
return that._mesh;
});
};
/**
* @private
*/
HeightmapTerrainData.prototype._createMeshSync = function (
tilingScheme,
x,
y,
level,
exaggeration
) {
//>>includeStart('debug', pragmas.debug);
if (!defined(tilingScheme)) {
throw new DeveloperError("tilingScheme is required.");
}
if (!defined(x)) {
throw new DeveloperError("x is required.");
}
if (!defined(y)) {
throw new DeveloperError("y is required.");
}
if (!defined(level)) {
throw new DeveloperError("level is required.");
}
//>>includeEnd('debug');
var ellipsoid = tilingScheme.ellipsoid;
var nativeRectangle = tilingScheme.tileXYToNativeRectangle(x, y, level);
var rectangle = tilingScheme.tileXYToRectangle(x, y, level);
exaggeration = defaultValue(exaggeration, 1.0);
// Compute the center of the tile for RTC rendering.
var center = ellipsoid.cartographicToCartesian(Rectangle.center(rectangle));
var structure = this._structure;
var levelZeroMaxError = TerrainProvider.getEstimatedLevelZeroGeometricErrorForAHeightmap(
ellipsoid,
this._width,
tilingScheme.getNumberOfXTilesAtLevel(0)
);
var thisLevelMaxError = levelZeroMaxError / (1 << level);
this._skirtHeight = Math.min(thisLevelMaxError * 4.0, 1000.0);
var result = HeightmapTessellator.computeVertices({
heightmap: this._buffer,
structure: structure,
includeWebMercatorT: true,
width: this._width,
height: this._height,
nativeRectangle: nativeRectangle,
rectangle: rectangle,
relativeToCenter: center,
ellipsoid: ellipsoid,
skirtHeight: this._skirtHeight,
isGeographic: tilingScheme.projection instanceof GeographicProjection,
exaggeration: exaggeration,
});
// Free memory received from server after mesh is created.
this._buffer = undefined;
var indicesAndEdges;
if (this._skirtHeight > 0.0) {
indicesAndEdges = TerrainProvider.getRegularGridAndSkirtIndicesAndEdgeIndices(
this._width,
this._height
);
} else {
indicesAndEdges = TerrainProvider.getRegularGridIndicesAndEdgeIndices(
this._width,
this._height
);
}
var vertexCountWithoutSkirts = result.gridWidth * result.gridHeight;
// No need to clone here (as we do in the async version) because the result
// is not coming from a web worker.
return new TerrainMesh(
center,
result.vertices,
indicesAndEdges.indices,
indicesAndEdges.indexCountWithoutSkirts,
vertexCountWithoutSkirts,
result.minimumHeight,
result.maximumHeight,
result.boundingSphere3D,
result.occludeePointInScaledSpace,
result.encoding.getStride(),
result.orientedBoundingBox,
result.encoding,
exaggeration,
indicesAndEdges.westIndicesSouthToNorth,
indicesAndEdges.southIndicesEastToWest,
indicesAndEdges.eastIndicesNorthToSouth,
indicesAndEdges.northIndicesWestToEast
);
};
/**
* Computes the terrain height at a specified longitude and latitude.
*
* @param {Rectangle} rectangle The rectangle covered by this terrain data.
* @param {Number} longitude The longitude in radians.
* @param {Number} latitude The latitude in radians.
* @returns {Number} The terrain height at the specified position. If the position
* is outside the rectangle, this method will extrapolate the height, which is likely to be wildly
* incorrect for positions far outside the rectangle.
*/
HeightmapTerrainData.prototype.interpolateHeight = function (
rectangle,
longitude,
latitude
) {
var width = this._width;
var height = this._height;
var structure = this._structure;
var stride = structure.stride;
var elementsPerHeight = structure.elementsPerHeight;
var elementMultiplier = structure.elementMultiplier;
var isBigEndian = structure.isBigEndian;
var heightOffset = structure.heightOffset;
var heightScale = structure.heightScale;
var heightSample;
if (defined(this._mesh)) {
var buffer = this._mesh.vertices;
var encoding = this._mesh.encoding;
var exaggeration = this._mesh.exaggeration;
heightSample = interpolateMeshHeight(
buffer,
encoding,
heightOffset,
heightScale,
rectangle,
width,
height,
longitude,
latitude,
exaggeration
);
} else {
heightSample = interpolateHeight(
this._buffer,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
rectangle,
width,
height,
longitude,
latitude
);
heightSample = heightSample * heightScale + heightOffset;
}
return heightSample;
};
/**
* Upsamples this terrain data for use by a descendant tile. The resulting instance will contain a subset of the
* height samples in this instance, interpolated if necessary.
*
* @param {TilingScheme} tilingScheme The tiling scheme of this terrain data.
* @param {Number} thisX The X coordinate of this tile in the tiling scheme.
* @param {Number} thisY The Y coordinate of this tile in the tiling scheme.
* @param {Number} thisLevel The level of this tile in the tiling scheme.
* @param {Number} descendantX The X coordinate within the tiling scheme of the descendant tile for which we are upsampling.
* @param {Number} descendantY The Y coordinate within the tiling scheme of the descendant tile for which we are upsampling.
* @param {Number} descendantLevel The level within the tiling scheme of the descendant tile for which we are upsampling.
* @returns {Promise.<HeightmapTerrainData>|undefined} A promise for upsampled heightmap terrain data for the descendant tile,
* or undefined if too many asynchronous upsample operations are in progress and the request has been
* deferred.
*/
HeightmapTerrainData.prototype.upsample = function (
tilingScheme,
thisX,
thisY,
thisLevel,
descendantX,
descendantY,
descendantLevel
) {
//>>includeStart('debug', pragmas.debug);
if (!defined(tilingScheme)) {
throw new DeveloperError("tilingScheme is required.");
}
if (!defined(thisX)) {
throw new DeveloperError("thisX is required.");
}
if (!defined(thisY)) {
throw new DeveloperError("thisY is required.");
}
if (!defined(thisLevel)) {
throw new DeveloperError("thisLevel is required.");
}
if (!defined(descendantX)) {
throw new DeveloperError("descendantX is required.");
}
if (!defined(descendantY)) {
throw new DeveloperError("descendantY is required.");
}
if (!defined(descendantLevel)) {
throw new DeveloperError("descendantLevel is required.");
}
var levelDifference = descendantLevel - thisLevel;
if (levelDifference > 1) {
throw new DeveloperError(
"Upsampling through more than one level at a time is not currently supported."
);
}
//>>includeEnd('debug');
var meshData = this._mesh;
if (!defined(meshData)) {
return undefined;
}
var width = this._width;
var height = this._height;
var structure = this._structure;
var stride = structure.stride;
var heights = new this._bufferType(width * height * stride);
var buffer = meshData.vertices;
var encoding = meshData.encoding;
// PERFORMANCE_IDEA: don't recompute these rectangles - the caller already knows them.
var sourceRectangle = tilingScheme.tileXYToRectangle(thisX, thisY, thisLevel);
var destinationRectangle = tilingScheme.tileXYToRectangle(
descendantX,
descendantY,
descendantLevel
);
var heightOffset = structure.heightOffset;
var heightScale = structure.heightScale;
var exaggeration = meshData.exaggeration;
var elementsPerHeight = structure.elementsPerHeight;
var elementMultiplier = structure.elementMultiplier;
var isBigEndian = structure.isBigEndian;
var divisor = Math.pow(elementMultiplier, elementsPerHeight - 1);
for (var j = 0; j < height; ++j) {
var latitude = CesiumMath.lerp(
destinationRectangle.north,
destinationRectangle.south,
j / (height - 1)
);
for (var i = 0; i < width; ++i) {
var longitude = CesiumMath.lerp(
destinationRectangle.west,
destinationRectangle.east,
i / (width - 1)
);
var heightSample = interpolateMeshHeight(
buffer,
encoding,
heightOffset,
heightScale,
sourceRectangle,
width,
height,
longitude,
latitude,
exaggeration
);
// Use conditionals here instead of Math.min and Math.max so that an undefined
// lowestEncodedHeight or highestEncodedHeight has no effect.
heightSample =
heightSample < structure.lowestEncodedHeight
? structure.lowestEncodedHeight
: heightSample;
heightSample =
heightSample > structure.highestEncodedHeight
? structure.highestEncodedHeight
: heightSample;
setHeight(
heights,
elementsPerHeight,
elementMultiplier,
divisor,
stride,
isBigEndian,
j * width + i,
heightSample
);
}
}
return new HeightmapTerrainData({
buffer: heights,
width: width,
height: height,
childTileMask: 0,
structure: this._structure,
createdByUpsampling: true,
});
};
/**
* Determines if a given child tile is available, based on the
* {@link HeightmapTerrainData.childTileMask}. The given child tile coordinates are assumed
* to be one of the four children of this tile. If non-child tile coordinates are
* given, the availability of the southeast child tile is returned.
*
* @param {Number} thisX The tile X coordinate of this (the parent) tile.
* @param {Number} thisY The tile Y coordinate of this (the parent) tile.
* @param {Number} childX The tile X coordinate of the child tile to check for availability.
* @param {Number} childY The tile Y coordinate of the child tile to check for availability.
* @returns {Boolean} True if the child tile is available; otherwise, false.
*/
HeightmapTerrainData.prototype.isChildAvailable = function (
thisX,
thisY,
childX,
childY
) {
//>>includeStart('debug', pragmas.debug);
if (!defined(thisX)) {
throw new DeveloperError("thisX is required.");
}
if (!defined(thisY)) {
throw new DeveloperError("thisY is required.");
}
if (!defined(childX)) {
throw new DeveloperError("childX is required.");
}
if (!defined(childY)) {
throw new DeveloperError("childY is required.");
}
//>>includeEnd('debug');
var bitNumber = 2; // northwest child
if (childX !== thisX * 2) {
++bitNumber; // east child
}
if (childY !== thisY * 2) {
bitNumber -= 2; // south child
}
return (this._childTileMask & (1 << bitNumber)) !== 0;
};
/**
* Gets a value indicating whether or not this terrain data was created by upsampling lower resolution
* terrain data. If this value is false, the data was obtained from some other source, such
* as by downloading it from a remote server. This method should return true for instances
* returned from a call to {@link HeightmapTerrainData#upsample}.
*
* @returns {Boolean} True if this instance was created by upsampling; otherwise, false.
*/
HeightmapTerrainData.prototype.wasCreatedByUpsampling = function () {
return this._createdByUpsampling;
};
function interpolateHeight(
sourceHeights,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
sourceRectangle,
width,
height,
longitude,
latitude
) {
var fromWest =
((longitude - sourceRectangle.west) * (width - 1)) /
(sourceRectangle.east - sourceRectangle.west);
var fromSouth =
((latitude - sourceRectangle.south) * (height - 1)) /
(sourceRectangle.north - sourceRectangle.south);
var westInteger = fromWest | 0;
var eastInteger = westInteger + 1;
if (eastInteger >= width) {
eastInteger = width - 1;
westInteger = width - 2;
}
var southInteger = fromSouth | 0;
var northInteger = southInteger + 1;
if (northInteger >= height) {
northInteger = height - 1;
southInteger = height - 2;
}
var dx = fromWest - westInteger;
var dy = fromSouth - southInteger;
southInteger = height - 1 - southInteger;
northInteger = height - 1 - northInteger;
var southwestHeight = getHeight(
sourceHeights,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
southInteger * width + westInteger
);
var southeastHeight = getHeight(
sourceHeights,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
southInteger * width + eastInteger
);
var northwestHeight = getHeight(
sourceHeights,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
northInteger * width + westInteger
);
var northeastHeight = getHeight(
sourceHeights,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
northInteger * width + eastInteger
);
return triangleInterpolateHeight(
dx,
dy,
southwestHeight,
southeastHeight,
northwestHeight,
northeastHeight
);
}
function interpolateMeshHeight(
buffer,
encoding,
heightOffset,
heightScale,
sourceRectangle,
width,
height,
longitude,
latitude,
exaggeration
) {
// returns a height encoded according to the structure's heightScale and heightOffset.
var fromWest =
((longitude - sourceRectangle.west) * (width - 1)) /
(sourceRectangle.east - sourceRectangle.west);
var fromSouth =
((latitude - sourceRectangle.south) * (height - 1)) /
(sourceRectangle.north - sourceRectangle.south);
var westInteger = fromWest | 0;
var eastInteger = westInteger + 1;
if (eastInteger >= width) {
eastInteger = width - 1;
westInteger = width - 2;
}
var southInteger = fromSouth | 0;
var northInteger = southInteger + 1;
if (northInteger >= height) {
northInteger = height - 1;
southInteger = height - 2;
}
var dx = fromWest - westInteger;
var dy = fromSouth - southInteger;
southInteger = height - 1 - southInteger;
northInteger = height - 1 - northInteger;
var southwestHeight =
(encoding.decodeHeight(buffer, southInteger * width + westInteger) /
exaggeration -
heightOffset) /
heightScale;
var southeastHeight =
(encoding.decodeHeight(buffer, southInteger * width + eastInteger) /
exaggeration -
heightOffset) /
heightScale;
var northwestHeight =
(encoding.decodeHeight(buffer, northInteger * width + westInteger) /
exaggeration -
heightOffset) /
heightScale;
var northeastHeight =
(encoding.decodeHeight(buffer, northInteger * width + eastInteger) /
exaggeration -
heightOffset) /
heightScale;
return triangleInterpolateHeight(
dx,
dy,
southwestHeight,
southeastHeight,
northwestHeight,
northeastHeight
);
}
function triangleInterpolateHeight(
dX,
dY,
southwestHeight,
southeastHeight,
northwestHeight,
northeastHeight
) {
// The HeightmapTessellator bisects the quad from southwest to northeast.
if (dY < dX) {
// Lower right triangle
return (
southwestHeight +
dX * (southeastHeight - southwestHeight) +
dY * (northeastHeight - southeastHeight)
);
}
// Upper left triangle
return (
southwestHeight +
dX * (northeastHeight - northwestHeight) +
dY * (northwestHeight - southwestHeight)
);
}
function getHeight(
heights,
elementsPerHeight,
elementMultiplier,
stride,
isBigEndian,
index
) {
index *= stride;
var height = 0;
var i;
if (isBigEndian) {
for (i = 0; i < elementsPerHeight; ++i) {
height = height * elementMultiplier + heights[index + i];
}
} else {
for (i = elementsPerHeight - 1; i >= 0; --i) {
height = height * elementMultiplier + heights[index + i];
}
}
return height;
}
function setHeight(
heights,
elementsPerHeight,
elementMultiplier,
divisor,
stride,
isBigEndian,
index,
height
) {
index *= stride;
var i;
if (isBigEndian) {
for (i = 0; i < elementsPerHeight - 1; ++i) {
heights[index + i] = (height / divisor) | 0;
height -= heights[index + i] * divisor;
divisor /= elementMultiplier;
}
} else {
for (i = elementsPerHeight - 1; i > 0; --i) {
heights[index + i] = (height / divisor) | 0;
height -= heights[index + i] * divisor;
divisor /= elementMultiplier;
}
}
heights[index + i] = height;
}
export default HeightmapTerrainData;