OpenTTD: src/tgp.cpp Source File

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tgp.cpp
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1 /* $Id: tgp.cpp 27334 2015-07-16 17:05:40Z frosch $ */
2
3 /*
4 * This file is part of OpenTTD.
5 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
6 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
7 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
8 */
9
12 #include "stdafx.h"
13 #include <math.h>
14 #include "clear_map.h"
15 #include "void_map.h"
16 #include "genworld.h"
17 #include "core/random_func.hpp"
18 #include "landscape_type.h"
19
20 #include "safeguards.h"
21
22 /*
23 *
24 * Quickie guide to Perlin Noise
25 * Perlin noise is a predictable pseudo random number sequence. By generating
26 * it in 2 dimensions, it becomes a useful random map that, for a given seed
27 * and starting X & Y, is entirely predictable. On the face of it, that may not
28 * be useful. However, it means that if you want to replay a map in a different
29 * terrain, or just vary the sea level, you just re-run the generator with the
30 * same seed. The seed is an int32, and is randomised on each run of New Game.
31 * The Scenario Generator does not randomise the value, so that you can
32 * experiment with one terrain until you are happy, or click "Random" for a new
33 * random seed.
34 *
35 * Perlin Noise is a series of "octaves" of random noise added together. By
36 * reducing the amplitude of the noise with each octave, the first octave of
37 * noise defines the main terrain sweep, the next the ripples on that, and the
38 * next the ripples on that. I use 6 octaves, with the amplitude controlled by
39 * a power ratio, usually known as a persistence or p value. This I vary by the
40 * smoothness selection, as can be seen in the table below. The closer to 1,
41 * the more of that octave is added. Each octave is however raised to the power
42 * of its position in the list, so the last entry in the "smooth" row, 0.35, is
43 * raised to the power of 6, so can only add 0.001838... of the amplitude to
44 * the running total.
45 *
46 * In other words; the first p value sets the general shape of the terrain, the
47 * second sets the major variations to that, ... until finally the smallest
48 * bumps are added.
49 *
50 * Usefully, this routine is totally scaleable; so when 32bpp comes along, the
51 * terrain can be as bumpy as you like! It is also infinitely expandable; a
52 * single random seed terrain continues in X & Y as far as you care to
53 * calculate. In theory, we could use just one seed value, but randomly select
54 * where in the Perlin XY space we use for the terrain. Personally I prefer
55 * using a simple (0, 0) to (X, Y), with a varying seed.
56 *
57 *
58 * Other things i have had to do: mountainous wasn't mountainous enough, and
59 * since we only have 0..15 heights available, I add a second generated map
60 * (with a modified seed), onto the original. This generally raises the
61 * terrain, which then needs scaling back down. Overall effect is a general
62 * uplift.
63 *
64 * However, the values on the top of mountains are then almost guaranteed to go
65 * too high, so large flat plateaus appeared at height 15. To counter this, I
66 * scale all heights above 12 to proportion up to 15. It still makes the
67 * mountains have flattish tops, rather than craggy peaks, but at least they
68 * aren't smooth as glass.
69 *
70 *
71 * For a full discussion of Perlin Noise, please visit:
72 * http://freespace.virgin.net/hugo.elias/models/m_perlin.htm
73 *
74 *
75 * Evolution II
76 *
77 * The algorithm as described in the above link suggests to compute each tile height
78 * as composition of several noise waves. Some of them are computed directly by
79 * noise(x, y) function, some are calculated using linear approximation. Our
80 * first implementation of perlin_noise_2D() used 4 noise(x, y) calls plus
81 * 3 linear interpolations. It was called 6 times for each tile. This was a bit
82 * CPU expensive.
83 *
84 * The following implementation uses optimized algorithm that should produce
85 * the same quality result with much less computations, but more memory accesses.
86 * The overall speedup should be 300% to 800% depending on CPU and memory speed.
87 *
88 * I will try to explain it on the example below:
89 *
90 * Have a map of 4 x 4 tiles, our simplified noise generator produces only two
91 * values -1 and +1, use 3 octaves with wave length 1, 2 and 4, with amplitudes
92 * 3, 2, 1. Original algorithm produces:
93 *
94 * h00 = lerp(lerp(-3, 3, 0/4), lerp(3, -3, 0/4), 0/4) + lerp(lerp(-2, 2, 0/2), lerp( 2, -2, 0/2), 0/2) + -1 = lerp(-3.0, 3.0, 0/4) + lerp(-2, 2, 0/2) + -1 = -3.0 + -2 + -1 = -6.0
95 * h01 = lerp(lerp(-3, 3, 1/4), lerp(3, -3, 1/4), 0/4) + lerp(lerp(-2, 2, 1/2), lerp( 2, -2, 1/2), 0/2) + 1 = lerp(-1.5, 1.5, 0/4) + lerp( 0, 0, 0/2) + 1 = -1.5 + 0 + 1 = -0.5
96 * h02 = lerp(lerp(-3, 3, 2/4), lerp(3, -3, 2/4), 0/4) + lerp(lerp( 2, -2, 0/2), lerp(-2, 2, 0/2), 0/2) + -1 = lerp( 0, 0, 0/4) + lerp( 2, -2, 0/2) + -1 = 0 + 2 + -1 = 1.0
97 * h03 = lerp(lerp(-3, 3, 3/4), lerp(3, -3, 3/4), 0/4) + lerp(lerp( 2, -2, 1/2), lerp(-2, 2, 1/2), 0/2) + 1 = lerp( 1.5, -1.5, 0/4) + lerp( 0, 0, 0/2) + 1 = 1.5 + 0 + 1 = 2.5
98 *
99 * h10 = lerp(lerp(-3, 3, 0/4), lerp(3, -3, 0/4), 1/4) + lerp(lerp(-2, 2, 0/2), lerp( 2, -2, 0/2), 1/2) + 1 = lerp(-3.0, 3.0, 1/4) + lerp(-2, 2, 1/2) + 1 = -1.5 + 0 + 1 = -0.5
100 * h11 = lerp(lerp(-3, 3, 1/4), lerp(3, -3, 1/4), 1/4) + lerp(lerp(-2, 2, 1/2), lerp( 2, -2, 1/2), 1/2) + -1 = lerp(-1.5, 1.5, 1/4) + lerp( 0, 0, 1/2) + -1 = -0.75 + 0 + -1 = -1.75
101 * h12 = lerp(lerp(-3, 3, 2/4), lerp(3, -3, 2/4), 1/4) + lerp(lerp( 2, -2, 0/2), lerp(-2, 2, 0/2), 1/2) + 1 = lerp( 0, 0, 1/4) + lerp( 2, -2, 1/2) + 1 = 0 + 0 + 1 = 1.0
102 * h13 = lerp(lerp(-3, 3, 3/4), lerp(3, -3, 3/4), 1/4) + lerp(lerp( 2, -2, 1/2), lerp(-2, 2, 1/2), 1/2) + -1 = lerp( 1.5, -1.5, 1/4) + lerp( 0, 0, 1/2) + -1 = 0.75 + 0 + -1 = -0.25
103 *
104 *
105 * Optimization 1:
106 *
107 * 1) we need to allocate a bit more tiles: (size_x + 1) * (size_y + 1) = (5 * 5):
108 *
109 * 2) setup corner values using amplitude 3
110 * { -3.0 X X X 3.0 }
111 * { X X X X X }
112 * { X X X X X }
113 * { X X X X X }
114 * { 3.0 X X X -3.0 }
115 *
116 * 3a) interpolate values in the middle
117 * { -3.0 X 0.0 X 3.0 }
118 * { X X X X X }
119 * { 0.0 X 0.0 X 0.0 }
120 * { X X X X X }
121 * { 3.0 X 0.0 X -3.0 }
122 *
123 * 3b) add patches with amplitude 2 to them
124 * { -5.0 X 2.0 X 1.0 }
125 * { X X X X X }
126 * { 2.0 X -2.0 X 2.0 }
127 * { X X X X X }
128 * { 1.0 X 2.0 X -5.0 }
129 *
130 * 4a) interpolate values in the middle
131 * { -5.0 -1.5 2.0 1.5 1.0 }
132 * { -1.5 -0.75 0.0 0.75 1.5 }
133 * { 2.0 0.0 -2.0 0.0 2.0 }
134 * { 1.5 0.75 0.0 -0.75 -1.5 }
135 * { 1.0 1.5 2.0 -1.5 -5.0 }
136 *
137 * 4b) add patches with amplitude 1 to them
138 * { -6.0 -0.5 1.0 2.5 0.0 }
139 * { -0.5 -1.75 1.0 -0.25 2.5 }
140 * { 1.0 1.0 -3.0 1.0 1.0 }
141 * { 2.5 -0.25 1.0 -1.75 -0.5 }
142 * { 0.0 2.5 1.0 -0.5 -6.0 }
143 *
144 *
145 *
146 * Optimization 2:
147 *
148 * As you can see above, each noise function was called just once. Therefore
149 * we don't need to use noise function that calculates the noise from x, y and
150 * some prime. The same quality result we can obtain using standard Random()
151 * function instead.
152 *
153 */
154
156 typedef int16 height_t;
157 static const int height_decimal_bits = 4;
158
160 typedef int amplitude_t;
161 static const int amplitude_decimal_bits = 10;
162
164 struct HeightMap
165 {
166 height_t *h; //< array of heights
167 /* Even though the sizes are always positive, there are many cases where
168 * X and Y need to be signed integers due to subtractions. */
169 int dim_x; //< height map size_x MapSizeX() + 1
170 int total_size; //< height map total size
171 int size_x; //< MapSizeX()
172 int size_y; //< MapSizeY()
173
180 inline height_t &height(uint x, uint y)
181 {
182 return h[x + y * dim_x];
183 }
184 };
185
187 static HeightMap _height_map = {NULL, 0, 0, 0, 0};
188
190 #define I2H(i) ((i) << height_decimal_bits)
191
192 #define H2I(i) ((i) >> height_decimal_bits)
193
195 #define I2A(i) ((i) << amplitude_decimal_bits)
196
197 #define A2I(i) ((i) >> amplitude_decimal_bits)
198
200 #define A2H(a) ((a) >> (amplitude_decimal_bits - height_decimal_bits))
201
202
204 #define FOR_ALL_TILES_IN_HEIGHT(h) for (h = _height_map.h; h < &_height_map.h[_height_map.total_size]; h++)
205
207 static const int MAX_TGP_FREQUENCIES = 10;
208
210 static const amplitude_t _water_percent[4] = {70, 170, 270, 420};
211
218 static height_t TGPGetMaxHeight()
219 {
230 static const int max_height[5][MAX_MAP_SIZE_BITS - MIN_MAP_SIZE_BITS + 1] = {
231 /* 64 128 256 512 1024 2048 4096 */
232 { 3, 3, 3, 3, 4, 5, 7 },
233 { 5, 7, 8, 9, 14, 19, 31 },
234 { 8, 9, 10, 15, 23, 37, 61 },
235 { 10, 11, 17, 19, 49, 63, 73 },
236 { 12, 19, 25, 31, 67, 75, 87 },
237 };
238
239 int max_height_from_table = max_height[_settings_game.difficulty.terrain_type][min(MapLogX(), MapLogY()) - MIN_MAP_SIZE_BITS];
240 return I2H(min(max_height_from_table, _settings_game.construction.max_heightlevel));
241 }
242
249 static amplitude_t GetAmplitude(int frequency)
250 {
251 /* Base noise amplitudes (multiplied by 1024) and indexed by "smoothness setting" and log2(frequency). */
252 static const amplitude_t amplitudes[][7] = {
253 /* lowest frequency ...... highest (every corner) */
254 {16000, 5600, 1968, 688, 240, 16, 16},
255 {24000, 12800, 6400, 2700, 1024, 128, 16},
256 {32000, 19200, 12800, 8000, 3200, 256, 64},
257 {48000, 24000, 19200, 16000, 8000, 512, 320},
258 };
259 /*
260 * Extrapolation factors for ranges before the table.
261 * The extrapolation is needed to account for the higher map heights. They need larger
262 * areas with a particular gradient so that we are able to create maps without too
263 * many steep slopes up to the wanted height level. It's definitely not perfect since
264 * it will bring larger rectangles with similar slopes which makes the rectangular
265 * behaviour of TGP more noticable. However, these height differentiations cannot
266 * happen over much smaller areas; we basically double the "range" to give a similar
267 * slope for every doubling of map height.
268 */
269 static const double extrapolation_factors[] = { 3.3, 2.8, 2.3, 1.8 };
270
271 int smoothness = _settings_game.game_creation.tgen_smoothness;
272
273 /* Get the table index, and return that value if possible. */
274 int index = frequency - MAX_TGP_FREQUENCIES + lengthof(amplitudes[smoothness]);
275 amplitude_t amplitude = amplitudes[smoothness][max(0, index)];
276 if (index >= 0) return amplitude;
277
278 /* We need to extrapolate the amplitude. */
279 double extrapolation_factor = extrapolation_factors[smoothness];
280 int height_range = I2H(16);
281 do {
282 amplitude = (amplitude_t)(extrapolation_factor * (double)amplitude);
283 height_range <<= 1;
284 index++;
285 } while (index < 0);
286
287 return Clamp((TGPGetMaxHeight() - height_range) / height_range, 0, 1) * amplitude;
288 }
289
296 static inline bool IsValidXY(int x, int y)
297 {
298 return x >= 0 && x < _height_map.size_x && y >= 0 && y < _height_map.size_y;
299 }
300
301
306 static inline bool AllocHeightMap()
307 {
308 height_t *h;
309
310 _height_map.size_x = MapSizeX();
311 _height_map.size_y = MapSizeY();
312
313 /* Allocate memory block for height map row pointers */
314 _height_map.total_size = (_height_map.size_x + 1) * (_height_map.size_y + 1);
315 _height_map.dim_x = _height_map.size_x + 1;
316 _height_map.h = CallocT<height_t>(_height_map.total_size);
317
318 /* Iterate through height map and initialise values. */
319 FOR_ALL_TILES_IN_HEIGHT(h) *h = 0;
320
321 return true;
322 }
323
325 static inline void FreeHeightMap()
326 {
327 free(_height_map.h);
328 _height_map.h = NULL;
329 }
330
336 static inline height_t RandomHeight(amplitude_t rMax)
337 {
338 /* Spread height into range -rMax..+rMax */
339 return A2H(RandomRange(2 * rMax + 1) - rMax);
340 }
341
349 static void HeightMapGenerate()
350 {
351 /* Trying to apply noise to uninitialized height map */
352 assert(_height_map.h != NULL);
353
354 int start = max(MAX_TGP_FREQUENCIES - (int)min(MapLogX(), MapLogY()), 0);
355 bool first = true;
356
357 for (int frequency = start; frequency < MAX_TGP_FREQUENCIES; frequency++) {
358 const amplitude_t amplitude = GetAmplitude(frequency);
359
360 /* Ignore zero amplitudes; it means our map isn't height enough for this
361 * amplitude, so ignore it and continue with the next set of amplitude. */
362 if (amplitude == 0) continue;
363
364 const int step = 1 << (MAX_TGP_FREQUENCIES - frequency - 1);
365
366 if (first) {
367 /* This is first round, we need to establish base heights with step = size_min */
368 for (int y = 0; y <= _height_map.size_y; y += step) {
369 for (int x = 0; x <= _height_map.size_x; x += step) {
370 height_t height = (amplitude > 0) ? RandomHeight(amplitude) : 0;
371 _height_map.height(x, y) = height;
372 }
373 }
374 first = false;
375 continue;
376 }
377
378 /* It is regular iteration round.
379 * Interpolate height values at odd x, even y tiles */
380 for (int y = 0; y <= _height_map.size_y; y += 2 * step) {
381 for (int x = 0; x <= _height_map.size_x - 2 * step; x += 2 * step) {
382 height_t h00 = _height_map.height(x + 0 * step, y);
383 height_t h02 = _height_map.height(x + 2 * step, y);
384 height_t h01 = (h00 + h02) / 2;
385 _height_map.height(x + 1 * step, y) = h01;
386 }
387 }
388
389 /* Interpolate height values at odd y tiles */
390 for (int y = 0; y <= _height_map.size_y - 2 * step; y += 2 * step) {
391 for (int x = 0; x <= _height_map.size_x; x += step) {
392 height_t h00 = _height_map.height(x, y + 0 * step);
393 height_t h20 = _height_map.height(x, y + 2 * step);
394 height_t h10 = (h00 + h20) / 2;
395 _height_map.height(x, y + 1 * step) = h10;
396 }
397 }
398
399 /* Add noise for next higher frequency (smaller steps) */
400 for (int y = 0; y <= _height_map.size_y; y += step) {
401 for (int x = 0; x <= _height_map.size_x; x += step) {
402 _height_map.height(x, y) += RandomHeight(amplitude);
403 }
404 }
405 }
406 }
407
409 static void HeightMapGetMinMaxAvg(height_t *min_ptr, height_t *max_ptr, height_t *avg_ptr)
410 {
411 height_t h_min, h_max, h_avg, *h;
412 int64 h_accu = 0;
413 h_min = h_max = _height_map.height(0, 0);
414
415 /* Get h_min, h_max and accumulate heights into h_accu */
416 FOR_ALL_TILES_IN_HEIGHT(h) {
417 if (*h < h_min) h_min = *h;
418 if (*h > h_max) h_max = *h;
419 h_accu += *h;
420 }
421
422 /* Get average height */
423 h_avg = (height_t)(h_accu / (_height_map.size_x * _height_map.size_y));
424
425 /* Return required results */
426 if (min_ptr != NULL) *min_ptr = h_min;
427 if (max_ptr != NULL) *max_ptr = h_max;
428 if (avg_ptr != NULL) *avg_ptr = h_avg;
429 }
430
432 static int *HeightMapMakeHistogram(height_t h_min, height_t h_max, int *hist_buf)
433 {
434 int *hist = hist_buf - h_min;
435 height_t *h;
436
437 /* Count the heights and fill the histogram */
438 FOR_ALL_TILES_IN_HEIGHT(h) {
439 assert(*h >= h_min);
440 assert(*h <= h_max);
441 hist[*h]++;
442 }
443 return hist;
444 }
445
447 static void HeightMapSineTransform(height_t h_min, height_t h_max)
448 {
449 height_t *h;
450
451 FOR_ALL_TILES_IN_HEIGHT(h) {
452 double fheight;
453
454 if (*h < h_min) continue;
455
456 /* Transform height into 0..1 space */
457 fheight = (double)(*h - h_min) / (double)(h_max - h_min);
458 /* Apply sine transform depending on landscape type */
459 switch (_settings_game.game_creation.landscape) {
460 case LT_TOYLAND:
461 case LT_TEMPERATE:
462 /* Move and scale 0..1 into -1..+1 */
463 fheight = 2 * fheight - 1;
464 /* Sine transform */
465 fheight = sin(fheight * M_PI_2);
466 /* Transform it back from -1..1 into 0..1 space */
467 fheight = 0.5 * (fheight + 1);
468 break;
469
470 case LT_ARCTIC:
471 {
472 /* Arctic terrain needs special height distribution.
473 * Redistribute heights to have more tiles at highest (75%..100%) range */
474 double sine_upper_limit = 0.75;
475 double linear_compression = 2;
476 if (fheight >= sine_upper_limit) {
477 /* Over the limit we do linear compression up */
478 fheight = 1.0 - (1.0 - fheight) / linear_compression;
479 } else {
480 double m = 1.0 - (1.0 - sine_upper_limit) / linear_compression;
481 /* Get 0..sine_upper_limit into -1..1 */
482 fheight = 2.0 * fheight / sine_upper_limit - 1.0;
483 /* Sine wave transform */
484 fheight = sin(fheight * M_PI_2);
485 /* Get -1..1 back to 0..(1 - (1 - sine_upper_limit) / linear_compression) == 0.0..m */
486 fheight = 0.5 * (fheight + 1.0) * m;
487 }
488 }
489 break;
490
491 case LT_TROPIC:
492 {
493 /* Desert terrain needs special height distribution.
494 * Half of tiles should be at lowest (0..25%) heights */
495 double sine_lower_limit = 0.5;
496 double linear_compression = 2;
497 if (fheight <= sine_lower_limit) {
498 /* Under the limit we do linear compression down */
499 fheight = fheight / linear_compression;
500 } else {
501 double m = sine_lower_limit / linear_compression;
502 /* Get sine_lower_limit..1 into -1..1 */
503 fheight = 2.0 * ((fheight - sine_lower_limit) / (1.0 - sine_lower_limit)) - 1.0;
504 /* Sine wave transform */
505 fheight = sin(fheight * M_PI_2);
506 /* Get -1..1 back to (sine_lower_limit / linear_compression)..1.0 */
507 fheight = 0.5 * ((1.0 - m) * fheight + (1.0 + m));
508 }
509 }
510 break;
511
512 default:
513 NOT_REACHED();
514 break;
515 }
516 /* Transform it back into h_min..h_max space */
517 *h = (height_t)(fheight * (h_max - h_min) + h_min);
518 if (*h < 0) *h = I2H(0);
519 if (*h >= h_max) *h = h_max - 1;
520 }
521 }
522
539 static void HeightMapCurves(uint level)
540 {
541 height_t mh = TGPGetMaxHeight() - I2H(1); // height levels above sea level only
542
544 struct control_point_t {
545 height_t x;
546 height_t y;
547 };
548 /* Scaled curve maps; value is in height_ts. */
549 #define F(fraction) ((height_t)(fraction * mh))
550 const control_point_t curve_map_1[] = { { F(0.0), F(0.0) }, { F(0.8), F(0.13) }, { F(1.0), F(0.4) } };
551 const control_point_t curve_map_2[] = { { F(0.0), F(0.0) }, { F(0.53), F(0.13) }, { F(0.8), F(0.27) }, { F(1.0), F(0.6) } };
552 const control_point_t curve_map_3[] = { { F(0.0), F(0.0) }, { F(0.53), F(0.27) }, { F(0.8), F(0.57) }, { F(1.0), F(0.8) } };
553 const control_point_t curve_map_4[] = { { F(0.0), F(0.0) }, { F(0.4), F(0.3) }, { F(0.7), F(0.8) }, { F(0.92), F(0.99) }, { F(1.0), F(0.99) } };
554 #undef F
555
557 struct control_point_list_t {
558 size_t length;
559 const control_point_t *list;
560 };
561 const control_point_list_t curve_maps[] = {
562 { lengthof(curve_map_1), curve_map_1 },
563 { lengthof(curve_map_2), curve_map_2 },
564 { lengthof(curve_map_3), curve_map_3 },
565 { lengthof(curve_map_4), curve_map_4 },
566 };
567
568 height_t ht[lengthof(curve_maps)];
569 MemSetT(ht, 0, lengthof(ht));
570
571 /* Set up a grid to choose curve maps based on location; attempt to get a somewhat square grid */
572 float factor = sqrt((float)_height_map.size_x / (float)_height_map.size_y);
573 uint sx = Clamp((int)(((1 << level) * factor) + 0.5), 1, 128);
574 uint sy = Clamp((int)(((1 << level) / factor) + 0.5), 1, 128);
575 byte *c = AllocaM(byte, sx * sy);
576
577 for (uint i = 0; i < sx * sy; i++) {
578 c[i] = Random() % lengthof(curve_maps);
579 }
580
581 /* Apply curves */
582 for (int x = 0; x < _height_map.size_x; x++) {
583
584 /* Get our X grid positions and bi-linear ratio */
585 float fx = (float)(sx * x) / _height_map.size_x + 1.0f;
586 uint x1 = (uint)fx;
587 uint x2 = x1;
588 float xr = 2.0f * (fx - x1) - 1.0f;
589 xr = sin(xr * M_PI_2);
590 xr = sin(xr * M_PI_2);
591 xr = 0.5f * (xr + 1.0f);
592 float xri = 1.0f - xr;
593
594 if (x1 > 0) {
595 x1--;
596 if (x2 >= sx) x2--;
597 }
598
599 for (int y = 0; y < _height_map.size_y; y++) {
600
601 /* Get our Y grid position and bi-linear ratio */
602 float fy = (float)(sy * y) / _height_map.size_y + 1.0f;
603 uint y1 = (uint)fy;
604 uint y2 = y1;
605 float yr = 2.0f * (fy - y1) - 1.0f;
606 yr = sin(yr * M_PI_2);
607 yr = sin(yr * M_PI_2);
608 yr = 0.5f * (yr + 1.0f);
609 float yri = 1.0f - yr;
610
611 if (y1 > 0) {
612 y1--;
613 if (y2 >= sy) y2--;
614 }
615
616 uint corner_a = c[x1 + sx * y1];
617 uint corner_b = c[x1 + sx * y2];
618 uint corner_c = c[x2 + sx * y1];
619 uint corner_d = c[x2 + sx * y2];
620
621 /* Bitmask of which curve maps are chosen, so that we do not bother
622 * calculating a curve which won't be used. */
623 uint corner_bits = 0;
624 corner_bits |= 1 << corner_a;
625 corner_bits |= 1 << corner_b;
626 corner_bits |= 1 << corner_c;
627 corner_bits |= 1 << corner_d;
628
629 height_t *h = &_height_map.height(x, y);
630
631 /* Do not touch sea level */
632 if (*h < I2H(1)) continue;
633
634 /* Only scale above sea level */
635 *h -= I2H(1);
636
637 /* Apply all curve maps that are used on this tile. */
638 for (uint t = 0; t < lengthof(curve_maps); t++) {
639 if (!HasBit(corner_bits, t)) continue;
640
641 bool found = false;
642 const control_point_t *cm = curve_maps[t].list;
643 for (uint i = 0; i < curve_maps[t].length - 1; i++) {
644 const control_point_t &p1 = cm[i];
645 const control_point_t &p2 = cm[i + 1];
646
647 if (*h >= p1.x && *h < p2.x) {
648 ht[t] = p1.y + (*h - p1.x) * (p2.y - p1.y) / (p2.x - p1.x);
649 found = true;
650 break;
651 }
652 }
653 assert(found);
654 }
655
656 /* Apply interpolation of curve map results. */
657 *h = (height_t)((ht[corner_a] * yri + ht[corner_b] * yr) * xri + (ht[corner_c] * yri + ht[corner_d] * yr) * xr);
658
659 /* Readd sea level */
660 *h += I2H(1);
661 }
662 }
663 }
664
666 static void HeightMapAdjustWaterLevel(amplitude_t water_percent, height_t h_max_new)
667 {
668 height_t h_min, h_max, h_avg, h_water_level;
669 int64 water_tiles, desired_water_tiles;
670 height_t *h;
671 int *hist;
672
673 HeightMapGetMinMaxAvg(&h_min, &h_max, &h_avg);
674
675 /* Allocate histogram buffer and clear its cells */
676 int *hist_buf = CallocT<int>(h_max - h_min + 1);
677 /* Fill histogram */
678 hist = HeightMapMakeHistogram(h_min, h_max, hist_buf);
679
680 /* How many water tiles do we want? */
681 desired_water_tiles = A2I(((int64)water_percent) * (int64)(_height_map.size_x * _height_map.size_y));
682
683 /* Raise water_level and accumulate values from histogram until we reach required number of water tiles */
684 for (h_water_level = h_min, water_tiles = 0; h_water_level < h_max; h_water_level++) {
685 water_tiles += hist[h_water_level];
686 if (water_tiles >= desired_water_tiles) break;
687 }
688
689 /* We now have the proper water level value.
690 * Transform the height map into new (normalized) height map:
691 * values from range: h_min..h_water_level will become negative so it will be clamped to 0
692 * values from range: h_water_level..h_max are transformed into 0..h_max_new
693 * where h_max_new is depending on terrain type and map size.
694 */
695 FOR_ALL_TILES_IN_HEIGHT(h) {
696 /* Transform height from range h_water_level..h_max into 0..h_max_new range */
697 *h = (height_t)(((int)h_max_new) * (*h - h_water_level) / (h_max - h_water_level)) + I2H(1);
698 /* Make sure all values are in the proper range (0..h_max_new) */
699 if (*h < 0) *h = I2H(0);
700 if (*h >= h_max_new) *h = h_max_new - 1;
701 }
702
703 free(hist_buf);
704 }
705
706 static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime);
707
728 static void HeightMapCoastLines(uint8 water_borders)
729 {
730 int smallest_size = min(_settings_game.game_creation.map_x, _settings_game.game_creation.map_y);
731 const int margin = 4;
732 int y, x;
733 double max_x;
734 double max_y;
735
736 /* Lower to sea level */
737 for (y = 0; y <= _height_map.size_y; y++) {
738 if (HasBit(water_borders, BORDER_NE)) {
739 /* Top right */
740 max_x = abs((perlin_coast_noise_2D(_height_map.size_y - y, y, 0.9, 53) + 0.25) * 5 + (perlin_coast_noise_2D(y, y, 0.35, 179) + 1) * 12);
741 max_x = max((smallest_size * smallest_size / 64) + max_x, (smallest_size * smallest_size / 64) + margin - max_x);
742 if (smallest_size < 8 && max_x > 5) max_x /= 1.5;
743 for (x = 0; x < max_x; x++) {
744 _height_map.height(x, y) = 0;
745 }
746 }
747
748 if (HasBit(water_borders, BORDER_SW)) {
749 /* Bottom left */
750 max_x = abs((perlin_coast_noise_2D(_height_map.size_y - y, y, 0.85, 101) + 0.3) * 6 + (perlin_coast_noise_2D(y, y, 0.45, 67) + 0.75) * 8);
751 max_x = max((smallest_size * smallest_size / 64) + max_x, (smallest_size * smallest_size / 64) + margin - max_x);
752 if (smallest_size < 8 && max_x > 5) max_x /= 1.5;
753 for (x = _height_map.size_x; x > (_height_map.size_x - 1 - max_x); x--) {
754 _height_map.height(x, y) = 0;
755 }
756 }
757 }
758
759 /* Lower to sea level */
760 for (x = 0; x <= _height_map.size_x; x++) {
761 if (HasBit(water_borders, BORDER_NW)) {
762 /* Top left */
763 max_y = abs((perlin_coast_noise_2D(x, _height_map.size_y / 2, 0.9, 167) + 0.4) * 5 + (perlin_coast_noise_2D(x, _height_map.size_y / 3, 0.4, 211) + 0.7) * 9);
764 max_y = max((smallest_size * smallest_size / 64) + max_y, (smallest_size * smallest_size / 64) + margin - max_y);
765 if (smallest_size < 8 && max_y > 5) max_y /= 1.5;
766 for (y = 0; y < max_y; y++) {
767 _height_map.height(x, y) = 0;
768 }
769 }
770
771 if (HasBit(water_borders, BORDER_SE)) {
772 /* Bottom right */
773 max_y = abs((perlin_coast_noise_2D(x, _height_map.size_y / 3, 0.85, 71) + 0.25) * 6 + (perlin_coast_noise_2D(x, _height_map.size_y / 3, 0.35, 193) + 0.75) * 12);
774 max_y = max((smallest_size * smallest_size / 64) + max_y, (smallest_size * smallest_size / 64) + margin - max_y);
775 if (smallest_size < 8 && max_y > 5) max_y /= 1.5;
776 for (y = _height_map.size_y; y > (_height_map.size_y - 1 - max_y); y--) {
777 _height_map.height(x, y) = 0;
778 }
779 }
780 }
781 }
782
784 static void HeightMapSmoothCoastInDirection(int org_x, int org_y, int dir_x, int dir_y)
785 {
786 const int max_coast_dist_from_edge = 35;
787 const int max_coast_Smooth_depth = 35;
788
789 int x, y;
790 int ed; // coast distance from edge
791 int depth;
792
793 height_t h_prev = I2H(1);
794 height_t h;
795
796 assert(IsValidXY(org_x, org_y));
797
798 /* Search for the coast (first non-water tile) */
799 for (x = org_x, y = org_y, ed = 0; IsValidXY(x, y) && ed < max_coast_dist_from_edge; x += dir_x, y += dir_y, ed++) {
800 /* Coast found? */
801 if (_height_map.height(x, y) >= I2H(1)) break;
802
803 /* Coast found in the neighborhood? */
804 if (IsValidXY(x + dir_y, y + dir_x) && _height_map.height(x + dir_y, y + dir_x) > 0) break;
805
806 /* Coast found in the neighborhood on the other side */
807 if (IsValidXY(x - dir_y, y - dir_x) && _height_map.height(x - dir_y, y - dir_x) > 0) break;
808 }
809
810 /* Coast found or max_coast_dist_from_edge has been reached.
811 * Soften the coast slope */
812 for (depth = 0; IsValidXY(x, y) && depth <= max_coast_Smooth_depth; depth++, x += dir_x, y += dir_y) {
813 h = _height_map.height(x, y);
814 h = min(h, h_prev + (4 + depth)); // coast softening formula
815 _height_map.height(x, y) = h;
816 h_prev = h;
817 }
818 }
819
821 static void HeightMapSmoothCoasts(uint8 water_borders)
822 {
823 int x, y;
824 /* First Smooth NW and SE coasts (y close to 0 and y close to size_y) */
825 for (x = 0; x < _height_map.size_x; x++) {
826 if (HasBit(water_borders, BORDER_NW)) HeightMapSmoothCoastInDirection(x, 0, 0, 1);
827 if (HasBit(water_borders, BORDER_SE)) HeightMapSmoothCoastInDirection(x, _height_map.size_y - 1, 0, -1);
828 }
829 /* First Smooth NE and SW coasts (x close to 0 and x close to size_x) */
830 for (y = 0; y < _height_map.size_y; y++) {
831 if (HasBit(water_borders, BORDER_NE)) HeightMapSmoothCoastInDirection(0, y, 1, 0);
832 if (HasBit(water_borders, BORDER_SW)) HeightMapSmoothCoastInDirection(_height_map.size_x - 1, y, -1, 0);
833 }
834 }
835
843 static void HeightMapSmoothSlopes(height_t dh_max)
844 {
845 for (int y = 0; y <= (int)_height_map.size_y; y++) {
846 for (int x = 0; x <= (int)_height_map.size_x; x++) {
847 height_t h_max = min(_height_map.height(x > 0 ? x - 1 : x, y), _height_map.height(x, y > 0 ? y - 1 : y)) + dh_max;
848 if (_height_map.height(x, y) > h_max) _height_map.height(x, y) = h_max;
849 }
850 }
851 for (int y = _height_map.size_y; y >= 0; y--) {
852 for (int x = _height_map.size_x; x >= 0; x--) {
853 height_t h_max = min(_height_map.height(x < _height_map.size_x ? x + 1 : x, y), _height_map.height(x, y < _height_map.size_y ? y + 1 : y)) + dh_max;
854 if (_height_map.height(x, y) > h_max) _height_map.height(x, y) = h_max;
855 }
856 }
857 }
858
866 static void HeightMapNormalize()
867 {
868 int sea_level_setting = _settings_game.difficulty.quantity_sea_lakes;
869 const amplitude_t water_percent = sea_level_setting != (int)CUSTOM_SEA_LEVEL_NUMBER_DIFFICULTY ? _water_percent[sea_level_setting] : _settings_game.game_creation.custom_sea_level * 1024 / 100;
870 const height_t h_max_new = TGPGetMaxHeight();
871 const height_t roughness = 7 + 3 * _settings_game.game_creation.tgen_smoothness;
872
873 HeightMapAdjustWaterLevel(water_percent, h_max_new);
874
875 byte water_borders = _settings_game.construction.freeform_edges ? _settings_game.game_creation.water_borders : 0xF;
876 if (water_borders == BORDERS_RANDOM) water_borders = GB(Random(), 0, 4);
877
878 HeightMapCoastLines(water_borders);
879 HeightMapSmoothSlopes(roughness);
880
881 HeightMapSmoothCoasts(water_borders);
882 HeightMapSmoothSlopes(roughness);
883
884 HeightMapSineTransform(I2H(1), h_max_new);
885
886 if (_settings_game.game_creation.variety > 0) {
887 HeightMapCurves(_settings_game.game_creation.variety);
888 }
889
890 HeightMapSmoothSlopes(I2H(1));
891 }
892
900 static double int_noise(const long x, const long y, const int prime)
901 {
902 long n = x + y * prime + _settings_game.game_creation.generation_seed;
903
904 n = (n << 13) ^ n;
905
906 /* Pseudo-random number generator, using several large primes */
907 return 1.0 - (double)((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0;
908 }
909
910
914 static inline double linear_interpolate(const double a, const double b, const double x)
915 {
916 return a + x * (b - a);
917 }
918
919
924 static double interpolated_noise(const double x, const double y, const int prime)
925 {
926 const int integer_X = (int)x;
927 const int integer_Y = (int)y;
928
929 const double fractional_X = x - (double)integer_X;
930 const double fractional_Y = y - (double)integer_Y;
931
932 const double v1 = int_noise(integer_X, integer_Y, prime);
933 const double v2 = int_noise(integer_X + 1, integer_Y, prime);
934 const double v3 = int_noise(integer_X, integer_Y + 1, prime);
935 const double v4 = int_noise(integer_X + 1, integer_Y + 1, prime);
936
937 const double i1 = linear_interpolate(v1, v2, fractional_X);
938 const double i2 = linear_interpolate(v3, v4, fractional_X);
939
940 return linear_interpolate(i1, i2, fractional_Y);
941 }
942
943
950 static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime)
951 {
952 double total = 0.0;
953
954 for (int i = 0; i < 6; i++) {
955 const double frequency = (double)(1 << i);
956 const double amplitude = pow(p, (double)i);
957
958 total += interpolated_noise((x * frequency) / 64.0, (y * frequency) / 64.0, prime) * amplitude;
959 }
960
961 return total;
962 }
963
964
966 static void TgenSetTileHeight(TileIndex tile, int height)
967 {
968 SetTileHeight(tile, height);
969
970 /* Only clear the tiles within the map area. */
971 if (IsInnerTile(tile)) {
972 MakeClear(tile, CLEAR_GRASS, 3);
973 }
974 }
975
983 void GenerateTerrainPerlin()
984 {
985 if (!AllocHeightMap()) return;
986 GenerateWorldSetAbortCallback(FreeHeightMap);
987
988 HeightMapGenerate();
989
990 IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
991
992 HeightMapNormalize();
993
994 IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
995
996 /* First make sure the tiles at the north border are void tiles if needed. */
997 if (_settings_game.construction.freeform_edges) {
998 for (int y = 0; y < _height_map.size_y - 1; y++) MakeVoid(_height_map.size_x * y);
999 for (int x = 0; x < _height_map.size_x; x++) MakeVoid(x);
1000 }
1001
1002 int max_height = H2I(TGPGetMaxHeight());
1003
1004 /* Transfer height map into OTTD map */
1005 for (int y = 0; y < _height_map.size_y; y++) {
1006 for (int x = 0; x < _height_map.size_x; x++) {
1007 TgenSetTileHeight(TileXY(x, y), Clamp(H2I(_height_map.height(x, y)), 0, max_height));
1008 }
1009 }
1010
1011 IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
1012
1013 FreeHeightMap();
1014 GenerateWorldSetAbortCallback(NULL);
1015 }