-
Notifications
You must be signed in to change notification settings - Fork 1
/
Terrain.js
371 lines (322 loc) · 10.6 KB
/
Terrain.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
let cross2d = (u, v) => {
return u[0] * v[1] - u[1] * v[0]
}
class Gradient {
constructor(stops, resolution) {
this.stops = {}
this.resolution = resolution
stops.forEach(stop => {
this.setStop.apply(this, stop)
})
this.colors = []
for (let i = 0; i < resolution; i++) {
this.colors[i] = this.makeColor(i/resolution)
}
}
getColor(offset) {
return this.colors[Math.floor(offset * this.resolution)]
}
setStop(offset, r, g, b) {
this.stops[offset] = nj.array([r, g, b])
}
makeColor(offset) {
let offsets = _.keys(this.stops).map(x => Number(x))
let rgb
if (offset in this.stops) {
rgb = this.stops[offset]
}
else {
let start = _.max(offsets.filter(x => x <= offset))
let end = _.min(offsets.filter(x => x >= offset))
let diff = this.stops[end].subtract(this.stops[start])
let multiplier = (offset - start)/(end - start)
rgb = this.stops[start].add(diff.multiply(multiplier))
}
rgb.dtype = 'uint8'
return new THREE.Color(
`rgb(${rgb.get(0)}, ${rgb.get(1)}, ${rgb.get(2)})`
)
}
}
let gradient = new Gradient([
[0, 93, 71, 49 ], // brown
[0.25, 35, 75, 44 ], // dark green
[0.60, 114, 184, 72 ], // green
[0.70, 220, 232, 149], // tan
[1, 255, 255, 255] // white
], 32)
class Chunk {
constructor(LOD, width, depth, height, gridScale = 100, noiseScale = 0.05,
octaves = 3, lacunarity = 2, persistence = 0.5,
offsetX = 0, offsetZ = 0) {
this.LOD = LOD
this.width = width
this.depth = depth
this.height = height
this.gridScale = gridScale
this.octaves = octaves
this.lacunarity = lacunarity
this.persistence = persistence
this.offsetX = offsetX
this.offsetZ = offsetZ
this.id = Math.floor(Math.random() * 10000).toString()
let basis = noise.perlin2
// let basis = (x, y) => 1.5 - Math.abs(noise.perlin2(x, y))
this.generateHeightmap(basis, noiseScale, height * gridScale,
octaves, lacunarity, persistence)
this.mesh = this.makeGeometry()
this.mesh.name = this.id
}
generateHeightmap(basis, frequency, amplitude, octaves,
lacunarity, persistence) {
this.heightmap = nj.zeros([this.width + 1, this.depth + 1]).tolist()
let freqs = _.range(octaves).map(o => Math.pow(lacunarity, o))
let amps = _.range(octaves).map(o => Math.pow(persistence, o))
let amp, freq, total, offX, offZ, o, i, j
// for each point
for (i = 0; i < this.width + 1; i++) {
for (j = 0; j < this.depth + 1; j++) {
amp = amplitude
freq = frequency
total = 0
offX = this.offsetX / this.gridScale
offZ = this.offsetZ / this.gridScale
for (o = 0; o < octaves; o++) {
freq *= freqs[o]
amp *= amps[o]
total += basis((i + offX) * freq, (j + offZ) * freq) * amp
}
this.heightmap[j][i] = total
}
}
}
makeGeometry() {
let geometry = new THREE.Geometry()
let triangles
let ymin = -12000
let ymax = 12000
let yrange = ymax - ymin
let indices = []
let colors = []
// let material = new THREE.MeshNormalMaterial({
// side: THREE.DoubleSide
// })
let material = new THREE.MeshLambertMaterial({
vertexColors: THREE.VertexColors,
shading: THREE.SmoothShading
})
// for each cell
for (let i = 0; i < this.width; i++) {
for (let j = 0; j < this.depth; j++) {
// resets arrays without creating new objects
indices.length = 0
colors.length = 0
for (let di = i; di < i+2; di++) {
for (let dj = j; dj < j+2; dj++) {
let y = this.heightmap[dj][di]
geometry.vertices.push(new THREE.Vector3(
di * this.gridScale, y, dj * this.gridScale
))
indices.push(geometry.vertices.length - 1)
let color = gradient.getColor((y - ymin) / yrange)
if (color == null || y < ymin || y > ymax) {
setTimeout(() => {
throw new Error(`y value ${y} outside color gradient range`)
}, 100)
color = gradient.colors[0]
}
colors.push(color)
}
}
// added in this order:
// 0---2 i ->
// | \ |
// 1---3
//
// j
let face1 = new THREE.Face3(
indices[0], indices[1], indices[3]
)
face1.vertexColors.push(colors[0])
face1.vertexColors.push(colors[1])
face1.vertexColors.push(colors[3])
geometry.faces.push(face1)
let face2 = new THREE.Face3(
indices[0], indices[3], indices[2]
)
face2.vertexColors.push(colors[0])
face2.vertexColors.push(colors[3])
face2.vertexColors.push(colors[2])
geometry.faces.push(face2)
}
}
// shift all the vectors so y axis is centered
let dx = -this.width * this.gridScale / 2 + this.offsetX
let dz = -this.depth * this.gridScale / 2 + this.offsetZ
geometry.translate(dx, 0, dz)
geometry.computeFaceNormals()
let mesh = new THREE.Mesh(geometry, material)
return mesh
}
getHeight(cx, cz) {
// get the interpolated height
// heightmap indexing always starts from 0, 0,
// so inputs should be relative x and z from chunk corner
// within the chunk, x and z are scaled by this.gridScale
cx /= this.gridScale
cz /= this.gridScale
let x_ = Math.floor(cx)
let z_ = Math.floor(cz)
let dx = cx - x_
let dz = cz - z_
// origin in the top-left corner
//
// 00-10 x
// | \ |
// 01-11
//
// z
let p = [dx, dz]
let vDiag = [1, 1]
let vEdge
if (dx > dz) {
// in the top-right triangle
vEdge = [1, 0]
}
else {
// in the bottom-left triangle
vEdge = [0, 1]
}
// half the cross product is triangle area, total area is 1/2,
// so the fraction of total area is xprod / 2 / 0.5 == xprod
//
// 00
// v |\`
// E | \ ` vDiag
// d w11\ wD
// g | /p`. `
// e | / w00 `.`
// D----------11
let wD = Math.abs(cross2d(vDiag, p))
let w11 = Math.abs(cross2d(vEdge, p))
let w00 = 1 - w11 - wD
let y11 = this.heightmap[z_ + 1][x_ + 1]
let y00 = this.heightmap[z_][x_]
let yD = this.heightmap[z_ + vEdge[1]][x_ + vEdge[0]]
let result = y00 * w00 + y11 * w11 + yD * wD
if (result != null && !isNaN(result)) {
return result
}
return -2000
}
}
class Terrain {
constructor(LODMap, chunkWidth, chunkDepth, chunkHeight, gridScale,
noiseScale, octaves, lacunarity, persistence) {
this.LODMap = LODMap
this.chunkWidth = chunkWidth
this.chunkDepth = chunkDepth
this.chunkHeight = chunkHeight
this.gridScale = gridScale
this.noiseScale = noiseScale
this.octaves = octaves
this.lacunarity = lacunarity
this.persistence = persistence
this.chunks = {}
this.pendingChunks = {}
}
getHeight(x, z) {
// find the chunk it belongs to
let wx = this.chunkWidth * this.gridScale // width of one chunk
let wz = this.chunkDepth * this.gridScale // depth of one chunk
let ci = Math.floor((x + wx/2)/wx) // x index offset from center chunk
let cj = Math.floor((z + wz/2)/wz) // z index offset from center chunk
let cx = x - wx * (ci - 1/2) // x position relative to chunk
let cz = z - wz * (cj - 1/2) // z position relative to chunk
let chunk = this.chunks[[ci,cj].join('|')]
if (chunk) {
return chunk.getHeight(cx, cz)
}
return -2001
}
update(cameraPosition, scene) {
let { x, z } = cameraPosition
let wx = this.chunkWidth * this.gridScale
let wz = this.chunkDepth * this.gridScale
let ci = Math.floor((x + wx/2)/wx) // x index offset from center of the map
let cj = Math.floor((z + wz/2)/wz) // z index offset from center of the map
this.pendingChunk = false
for (let i = 0; i < this.LODMap.length; i++) { // x axis
for (let j = 0; j < this.LODMap[0].length; j++) { // z axis
let LOD = this.LODMap[j][i]
this.makeChunk(i + ci, j + cj, LOD, scene)
if (i !== 0) {
this.makeChunk(-i + ci, j + cj, LOD, scene)
}
if (j !== 0) {
this.makeChunk(i + ci, -j + cj, LOD, scene)
}
if (i !== 0 && j !== 0) {
this.makeChunk(-i + ci, -j + cj, LOD, scene)
}
}
}
}
makeKey(i, j) {
return [i,j].join('|')
}
makeChunk(i, j, targetLOD, scene) {
let key = this.makeKey(i, j)
let currentChunk = this.chunks[key]
let pendingChunk = this.pendingChunks[key]
if (targetLOD < 0) {
// just need delete the current chunk
if (currentChunk) {
// console.log(`deleting chunk at ${i}, ${j}`)
scene.remove(currentChunk.mesh)
}
delete this.chunks[key]
}
else if (currentChunk && currentChunk.LOD === targetLOD) {
// no need to change anything
return
}
else if (pendingChunk) {
// chunk is in progress, no need to do anything
return
}
else if (this.pendingChunk) {
return
}
else {
// need to make a new chunk
// console.log(`queuing new chunk at ${i}, ${j}`)
this.pendingChunks[key] = true
this.pendingChunk = true
setTimeout(() => {
let scale = Math.pow(2, targetLOD)
let w = this.chunkWidth / scale
let d = this.chunkDepth / scale
let h = this.chunkHeight / scale
let gs = this.gridScale * scale
let ns = this.noiseScale * scale
// chunk position relative to center
let offsetX = i * w * gs
let offsetZ = j * d * gs
let newChunk = new Chunk(
targetLOD, w, d, h, gs, ns,
this.octaves, this.lacunarity, this.persistence,
offsetX, offsetZ
)
// console.log(`finished new chunk at ${i}, ${j}`)
delete this.pendingChunks[key]
if (currentChunk) {
// console.log(`replacing old chunk at ${i}, ${j}`)
scene.remove(currentChunk.mesh)
}
scene.add(newChunk.mesh)
this.chunks[key] = newChunk
}, 1)
}
}
}