OpenTTD Source: src/tgp.cpp Source File

OpenTTD Source 13.2.1

tgp.cpp
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1 /*
2 * This file is part of OpenTTD.
3 * 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.
4 * 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.
5 * 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/>.
6 */
7
10 #include "stdafx.h"
11 #include <math.h>
12 #include "clear_map.h"
13 #include "void_map.h"
14 #include "genworld.h"
15 #include "core/random_func.hpp"
16 #include "landscape_type.h"
17
18 #include "safeguards.h"
19
20 /*
21 *
22 * Quickie guide to Perlin Noise
23 * Perlin noise is a predictable pseudo random number sequence. By generating
24 * it in 2 dimensions, it becomes a useful random map that, for a given seed
25 * and starting X & Y, is entirely predictable. On the face of it, that may not
26 * be useful. However, it means that if you want to replay a map in a different
27 * terrain, or just vary the sea level, you just re-run the generator with the
28 * same seed. The seed is an int32, and is randomised on each run of New Game.
29 * The Scenario Generator does not randomise the value, so that you can
30 * experiment with one terrain until you are happy, or click "Random" for a new
31 * random seed.
32 *
33 * Perlin Noise is a series of "octaves" of random noise added together. By
34 * reducing the amplitude of the noise with each octave, the first octave of
35 * noise defines the main terrain sweep, the next the ripples on that, and the
36 * next the ripples on that. I use 6 octaves, with the amplitude controlled by
37 * a power ratio, usually known as a persistence or p value. This I vary by the
38 * smoothness selection, as can be seen in the table below. The closer to 1,
39 * the more of that octave is added. Each octave is however raised to the power
40 * of its position in the list, so the last entry in the "smooth" row, 0.35, is
41 * raised to the power of 6, so can only add 0.001838... of the amplitude to
42 * the running total.
43 *
44 * In other words; the first p value sets the general shape of the terrain, the
45 * second sets the major variations to that, ... until finally the smallest
46 * bumps are added.
47 *
48 * Usefully, this routine is totally scalable; so when 32bpp comes along, the
49 * terrain can be as bumpy as you like! It is also infinitely expandable; a
50 * single random seed terrain continues in X & Y as far as you care to
51 * calculate. In theory, we could use just one seed value, but randomly select
52 * where in the Perlin XY space we use for the terrain. Personally I prefer
53 * using a simple (0, 0) to (X, Y), with a varying seed.
54 *
55 *
56 * Other things i have had to do: mountainous wasn't mountainous enough, and
57 * since we only have 0..15 heights available, I add a second generated map
58 * (with a modified seed), onto the original. This generally raises the
59 * terrain, which then needs scaling back down. Overall effect is a general
60 * uplift.
61 *
62 * However, the values on the top of mountains are then almost guaranteed to go
63 * too high, so large flat plateaus appeared at height 15. To counter this, I
64 * scale all heights above 12 to proportion up to 15. It still makes the
65 * mountains have flattish tops, rather than craggy peaks, but at least they
66 * aren't smooth as glass.
67 *
68 *
69 * For a full discussion of Perlin Noise, please visit:
70 * http://freespace.virgin.net/hugo.elias/models/m_perlin.htm
71 *
72 *
73 * Evolution II
74 *
75 * The algorithm as described in the above link suggests to compute each tile height
76 * as composition of several noise waves. Some of them are computed directly by
77 * noise(x, y) function, some are calculated using linear approximation. Our
78 * first implementation of perlin_noise_2D() used 4 noise(x, y) calls plus
79 * 3 linear interpolations. It was called 6 times for each tile. This was a bit
80 * CPU expensive.
81 *
82 * The following implementation uses optimized algorithm that should produce
83 * the same quality result with much less computations, but more memory accesses.
84 * The overall speedup should be 300% to 800% depending on CPU and memory speed.
85 *
86 * I will try to explain it on the example below:
87 *
88 * Have a map of 4 x 4 tiles, our simplified noise generator produces only two
89 * values -1 and +1, use 3 octaves with wave length 1, 2 and 4, with amplitudes
90 * 3, 2, 1. Original algorithm produces:
91 *
92 * 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
93 * 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
94 * 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
95 * 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
96 *
97 * 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
98 * 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
99 * 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
100 * 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
101 *
102 *
103 * Optimization 1:
104 *
105 * 1) we need to allocate a bit more tiles: (size_x + 1) * (size_y + 1) = (5 * 5):
106 *
107 * 2) setup corner values using amplitude 3
108 * { -3.0 X X X 3.0 }
109 * { X X X X X }
110 * { X X X X X }
111 * { X X X X X }
112 * { 3.0 X X X -3.0 }
113 *
114 * 3a) interpolate values in the middle
115 * { -3.0 X 0.0 X 3.0 }
116 * { X X X X X }
117 * { 0.0 X 0.0 X 0.0 }
118 * { X X X X X }
119 * { 3.0 X 0.0 X -3.0 }
120 *
121 * 3b) add patches with amplitude 2 to them
122 * { -5.0 X 2.0 X 1.0 }
123 * { X X X X X }
124 * { 2.0 X -2.0 X 2.0 }
125 * { X X X X X }
126 * { 1.0 X 2.0 X -5.0 }
127 *
128 * 4a) interpolate values in the middle
129 * { -5.0 -1.5 2.0 1.5 1.0 }
130 * { -1.5 -0.75 0.0 0.75 1.5 }
131 * { 2.0 0.0 -2.0 0.0 2.0 }
132 * { 1.5 0.75 0.0 -0.75 -1.5 }
133 * { 1.0 1.5 2.0 -1.5 -5.0 }
134 *
135 * 4b) add patches with amplitude 1 to them
136 * { -6.0 -0.5 1.0 2.5 0.0 }
137 * { -0.5 -1.75 1.0 -0.25 2.5 }
138 * { 1.0 1.0 -3.0 1.0 1.0 }
139 * { 2.5 -0.25 1.0 -1.75 -0.5 }
140 * { 0.0 2.5 1.0 -0.5 -6.0 }
141 *
142 *
143 *
144 * Optimization 2:
145 *
146 * As you can see above, each noise function was called just once. Therefore
147 * we don't need to use noise function that calculates the noise from x, y and
148 * some prime. The same quality result we can obtain using standard Random()
149 * function instead.
150 *
151 */
152
154 typedef int16 height_t;
155 static const int height_decimal_bits = 4;
156
158 typedef int amplitude_t;
159 static const int amplitude_decimal_bits = 10;
160
162 struct HeightMap
163 {
164 std::vector<height_t> h; //< array of heights
165 /* Even though the sizes are always positive, there are many cases where
166 * X and Y need to be signed integers due to subtractions. */
167 int dim_x; //< height map size_x MapSizeX() + 1
168 int size_x; //< MapSizeX()
169 int size_y; //< MapSizeY()
170
177 inline height_t &height(uint x, uint y)
178 {
179 return h[x + y * dim_x];
180 }
181 };
182
184 static HeightMap _height_map = { {}, 0, 0, 0 };
185
187 #define I2H(i) ((i) << height_decimal_bits)
188
189 #define H2I(i) ((i) >> height_decimal_bits)
190
192 #define I2A(i) ((i) << amplitude_decimal_bits)
193
194 #define A2I(i) ((i) >> amplitude_decimal_bits)
195
197 #define A2H(a) ((a) >> (amplitude_decimal_bits - height_decimal_bits))
198
200 static const int MAX_TGP_FREQUENCIES = 10;
201
203 static const amplitude_t _water_percent[4] = {70, 170, 270, 420};
204
211 static height_t TGPGetMaxHeight()
212 {
213 if (_settings_game.difficulty.terrain_type == CUSTOM_TERRAIN_TYPE_NUMBER_DIFFICULTY) {
214 /* TGP never reaches this height; this means that if a user inputs "2",
215 * it would create a flat map without the "+ 1". But that would
216 * overflow on "255". So we reduce it by 1 to get back in range. */
217 return I2H(_settings_game.game_creation.custom_terrain_type + 1) - 1;
218 }
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 map_size_bucket = std::min(MapLogX(), MapLogY()) - MIN_MAP_SIZE_BITS;
240 int max_height_from_table = max_height[_settings_game.difficulty.terrain_type][map_size_bucket];
241
242 /* If there is a manual map height limit, clamp to it. */
243 if (_settings_game.construction.map_height_limit != 0) {
244 max_height_from_table = std::min<uint>(max_height_from_table, _settings_game.construction.map_height_limit);
245 }
246
247 return I2H(max_height_from_table);
248 }
249
253 uint GetEstimationTGPMapHeight()
254 {
255 return H2I(TGPGetMaxHeight());
256 }
257
264 static amplitude_t GetAmplitude(int frequency)
265 {
266 /* Base noise amplitudes (multiplied by 1024) and indexed by "smoothness setting" and log2(frequency). */
267 static const amplitude_t amplitudes[][7] = {
268 /* lowest frequency ...... highest (every corner) */
269 {16000, 5600, 1968, 688, 240, 16, 16},
270 {24000, 12800, 6400, 2700, 1024, 128, 16},
271 {32000, 19200, 12800, 8000, 3200, 256, 64},
272 {48000, 24000, 19200, 16000, 8000, 512, 320},
273 };
274 /*
275 * Extrapolation factors for ranges before the table.
276 * The extrapolation is needed to account for the higher map heights. They need larger
277 * areas with a particular gradient so that we are able to create maps without too
278 * many steep slopes up to the wanted height level. It's definitely not perfect since
279 * it will bring larger rectangles with similar slopes which makes the rectangular
280 * behaviour of TGP more noticeable. However, these height differentiations cannot
281 * happen over much smaller areas; we basically double the "range" to give a similar
282 * slope for every doubling of map height.
283 */
284 static const double extrapolation_factors[] = { 3.3, 2.8, 2.3, 1.8 };
285
286 int smoothness = _settings_game.game_creation.tgen_smoothness;
287
288 /* Get the table index, and return that value if possible. */
289 int index = frequency - MAX_TGP_FREQUENCIES + lengthof(amplitudes[smoothness]);
290 amplitude_t amplitude = amplitudes[smoothness][std::max(0, index)];
291 if (index >= 0) return amplitude;
292
293 /* We need to extrapolate the amplitude. */
294 double extrapolation_factor = extrapolation_factors[smoothness];
295 int height_range = I2H(16);
296 do {
297 amplitude = (amplitude_t)(extrapolation_factor * (double)amplitude);
298 height_range <<= 1;
299 index++;
300 } while (index < 0);
301
302 return Clamp((TGPGetMaxHeight() - height_range) / height_range, 0, 1) * amplitude;
303 }
304
311 static inline bool IsValidXY(int x, int y)
312 {
313 return x >= 0 && x < _height_map.size_x && y >= 0 && y < _height_map.size_y;
314 }
315
316
321 static inline bool AllocHeightMap()
322 {
323 assert(_height_map.h.empty());
324
325 _height_map.size_x = MapSizeX();
326 _height_map.size_y = MapSizeY();
327
328 /* Allocate memory block for height map row pointers */
329 size_t total_size = (_height_map.size_x + 1) * (_height_map.size_y + 1);
330 _height_map.dim_x = _height_map.size_x + 1;
331 _height_map.h.resize(total_size);
332
333 return true;
334 }
335
337 static inline void FreeHeightMap()
338 {
339 _height_map.h.clear();
340 }
341
347 static inline height_t RandomHeight(amplitude_t rMax)
348 {
349 /* Spread height into range -rMax..+rMax */
350 return A2H(RandomRange(2 * rMax + 1) - rMax);
351 }
352
360 static void HeightMapGenerate()
361 {
362 /* Trying to apply noise to uninitialized height map */
363 assert(!_height_map.h.empty());
364
365 int start = std::max(MAX_TGP_FREQUENCIES - (int)std::min(MapLogX(), MapLogY()), 0);
366 bool first = true;
367
368 for (int frequency = start; frequency < MAX_TGP_FREQUENCIES; frequency++) {
369 const amplitude_t amplitude = GetAmplitude(frequency);
370
371 /* Ignore zero amplitudes; it means our map isn't height enough for this
372 * amplitude, so ignore it and continue with the next set of amplitude. */
373 if (amplitude == 0) continue;
374
375 const int step = 1 << (MAX_TGP_FREQUENCIES - frequency - 1);
376
377 if (first) {
378 /* This is first round, we need to establish base heights with step = size_min */
379 for (int y = 0; y <= _height_map.size_y; y += step) {
380 for (int x = 0; x <= _height_map.size_x; x += step) {
381 height_t height = (amplitude > 0) ? RandomHeight(amplitude) : 0;
382 _height_map.height(x, y) = height;
383 }
384 }
385 first = false;
386 continue;
387 }
388
389 /* It is regular iteration round.
390 * Interpolate height values at odd x, even y tiles */
391 for (int y = 0; y <= _height_map.size_y; y += 2 * step) {
392 for (int x = 0; x <= _height_map.size_x - 2 * step; x += 2 * step) {
393 height_t h00 = _height_map.height(x + 0 * step, y);
394 height_t h02 = _height_map.height(x + 2 * step, y);
395 height_t h01 = (h00 + h02) / 2;
396 _height_map.height(x + 1 * step, y) = h01;
397 }
398 }
399
400 /* Interpolate height values at odd y tiles */
401 for (int y = 0; y <= _height_map.size_y - 2 * step; y += 2 * step) {
402 for (int x = 0; x <= _height_map.size_x; x += step) {
403 height_t h00 = _height_map.height(x, y + 0 * step);
404 height_t h20 = _height_map.height(x, y + 2 * step);
405 height_t h10 = (h00 + h20) / 2;
406 _height_map.height(x, y + 1 * step) = h10;
407 }
408 }
409
410 /* Add noise for next higher frequency (smaller steps) */
411 for (int y = 0; y <= _height_map.size_y; y += step) {
412 for (int x = 0; x <= _height_map.size_x; x += step) {
413 _height_map.height(x, y) += RandomHeight(amplitude);
414 }
415 }
416 }
417 }
418
420 static void HeightMapGetMinMaxAvg(height_t *min_ptr, height_t *max_ptr, height_t *avg_ptr)
421 {
422 height_t h_min, h_max, h_avg;
423 int64 h_accu = 0;
424 h_min = h_max = _height_map.height(0, 0);
425
426 /* Get h_min, h_max and accumulate heights into h_accu */
427 for (const height_t &h : _height_map.h) {
428 if (h < h_min) h_min = h;
429 if (h > h_max) h_max = h;
430 h_accu += h;
431 }
432
433 /* Get average height */
434 h_avg = (height_t)(h_accu / (_height_map.size_x * _height_map.size_y));
435
436 /* Return required results */
437 if (min_ptr != nullptr) *min_ptr = h_min;
438 if (max_ptr != nullptr) *max_ptr = h_max;
439 if (avg_ptr != nullptr) *avg_ptr = h_avg;
440 }
441
443 static int *HeightMapMakeHistogram(height_t h_min, height_t h_max, int *hist_buf)
444 {
445 int *hist = hist_buf - h_min;
446
447 /* Count the heights and fill the histogram */
448 for (const height_t &h : _height_map.h){
449 assert(h >= h_min);
450 assert(h <= h_max);
451 hist[h]++;
452 }
453 return hist;
454 }
455
457 static void HeightMapSineTransform(height_t h_min, height_t h_max)
458 {
459 for (height_t &h : _height_map.h) {
460 double fheight;
461
462 if (h < h_min) continue;
463
464 /* Transform height into 0..1 space */
465 fheight = (double)(h - h_min) / (double)(h_max - h_min);
466 /* Apply sine transform depending on landscape type */
467 switch (_settings_game.game_creation.landscape) {
468 case LT_TOYLAND:
469 case LT_TEMPERATE:
470 /* Move and scale 0..1 into -1..+1 */
471 fheight = 2 * fheight - 1;
472 /* Sine transform */
473 fheight = sin(fheight * M_PI_2);
474 /* Transform it back from -1..1 into 0..1 space */
475 fheight = 0.5 * (fheight + 1);
476 break;
477
478 case LT_ARCTIC:
479 {
480 /* Arctic terrain needs special height distribution.
481 * Redistribute heights to have more tiles at highest (75%..100%) range */
482 double sine_upper_limit = 0.75;
483 double linear_compression = 2;
484 if (fheight >= sine_upper_limit) {
485 /* Over the limit we do linear compression up */
486 fheight = 1.0 - (1.0 - fheight) / linear_compression;
487 } else {
488 double m = 1.0 - (1.0 - sine_upper_limit) / linear_compression;
489 /* Get 0..sine_upper_limit into -1..1 */
490 fheight = 2.0 * fheight / sine_upper_limit - 1.0;
491 /* Sine wave transform */
492 fheight = sin(fheight * M_PI_2);
493 /* Get -1..1 back to 0..(1 - (1 - sine_upper_limit) / linear_compression) == 0.0..m */
494 fheight = 0.5 * (fheight + 1.0) * m;
495 }
496 }
497 break;
498
499 case LT_TROPIC:
500 {
501 /* Desert terrain needs special height distribution.
502 * Half of tiles should be at lowest (0..25%) heights */
503 double sine_lower_limit = 0.5;
504 double linear_compression = 2;
505 if (fheight <= sine_lower_limit) {
506 /* Under the limit we do linear compression down */
507 fheight = fheight / linear_compression;
508 } else {
509 double m = sine_lower_limit / linear_compression;
510 /* Get sine_lower_limit..1 into -1..1 */
511 fheight = 2.0 * ((fheight - sine_lower_limit) / (1.0 - sine_lower_limit)) - 1.0;
512 /* Sine wave transform */
513 fheight = sin(fheight * M_PI_2);
514 /* Get -1..1 back to (sine_lower_limit / linear_compression)..1.0 */
515 fheight = 0.5 * ((1.0 - m) * fheight + (1.0 + m));
516 }
517 }
518 break;
519
520 default:
521 NOT_REACHED();
522 break;
523 }
524 /* Transform it back into h_min..h_max space */
525 h = (height_t)(fheight * (h_max - h_min) + h_min);
526 if (h < 0) h = I2H(0);
527 if (h >= h_max) h = h_max - 1;
528 }
529 }
530
547 static void HeightMapCurves(uint level)
548 {
549 height_t mh = TGPGetMaxHeight() - I2H(1); // height levels above sea level only
550
552 struct control_point_t {
553 height_t x;
554 height_t y;
555 };
556 /* Scaled curve maps; value is in height_ts. */
557 #define F(fraction) ((height_t)(fraction * mh))
558 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) } };
559 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) } };
560 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) } };
561 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) } };
562 #undef F
563
565 struct control_point_list_t {
566 size_t length;
567 const control_point_t *list;
568 };
569 const control_point_list_t curve_maps[] = {
570 { lengthof(curve_map_1), curve_map_1 },
571 { lengthof(curve_map_2), curve_map_2 },
572 { lengthof(curve_map_3), curve_map_3 },
573 { lengthof(curve_map_4), curve_map_4 },
574 };
575
576 height_t ht[lengthof(curve_maps)];
577 MemSetT(ht, 0, lengthof(ht));
578
579 /* Set up a grid to choose curve maps based on location; attempt to get a somewhat square grid */
580 float factor = sqrt((float)_height_map.size_x / (float)_height_map.size_y);
581 uint sx = Clamp((int)(((1 << level) * factor) + 0.5), 1, 128);
582 uint sy = Clamp((int)(((1 << level) / factor) + 0.5), 1, 128);
583 byte *c = AllocaM(byte, sx * sy);
584
585 for (uint i = 0; i < sx * sy; i++) {
586 c[i] = Random() % lengthof(curve_maps);
587 }
588
589 /* Apply curves */
590 for (int x = 0; x < _height_map.size_x; x++) {
591
592 /* Get our X grid positions and bi-linear ratio */
593 float fx = (float)(sx * x) / _height_map.size_x + 1.0f;
594 uint x1 = (uint)fx;
595 uint x2 = x1;
596 float xr = 2.0f * (fx - x1) - 1.0f;
597 xr = sin(xr * M_PI_2);
598 xr = sin(xr * M_PI_2);
599 xr = 0.5f * (xr + 1.0f);
600 float xri = 1.0f - xr;
601
602 if (x1 > 0) {
603 x1--;
604 if (x2 >= sx) x2--;
605 }
606
607 for (int y = 0; y < _height_map.size_y; y++) {
608
609 /* Get our Y grid position and bi-linear ratio */
610 float fy = (float)(sy * y) / _height_map.size_y + 1.0f;
611 uint y1 = (uint)fy;
612 uint y2 = y1;
613 float yr = 2.0f * (fy - y1) - 1.0f;
614 yr = sin(yr * M_PI_2);
615 yr = sin(yr * M_PI_2);
616 yr = 0.5f * (yr + 1.0f);
617 float yri = 1.0f - yr;
618
619 if (y1 > 0) {
620 y1--;
621 if (y2 >= sy) y2--;
622 }
623
624 uint corner_a = c[x1 + sx * y1];
625 uint corner_b = c[x1 + sx * y2];
626 uint corner_c = c[x2 + sx * y1];
627 uint corner_d = c[x2 + sx * y2];
628
629 /* Bitmask of which curve maps are chosen, so that we do not bother
630 * calculating a curve which won't be used. */
631 uint corner_bits = 0;
632 corner_bits |= 1 << corner_a;
633 corner_bits |= 1 << corner_b;
634 corner_bits |= 1 << corner_c;
635 corner_bits |= 1 << corner_d;
636
637 height_t *h = &_height_map.height(x, y);
638
639 /* Do not touch sea level */
640 if (*h < I2H(1)) continue;
641
642 /* Only scale above sea level */
643 *h -= I2H(1);
644
645 /* Apply all curve maps that are used on this tile. */
646 for (uint t = 0; t < lengthof(curve_maps); t++) {
647 if (!HasBit(corner_bits, t)) continue;
648
649 [[maybe_unused]] bool found = false;
650 const control_point_t *cm = curve_maps[t].list;
651 for (uint i = 0; i < curve_maps[t].length - 1; i++) {
652 const control_point_t &p1 = cm[i];
653 const control_point_t &p2 = cm[i + 1];
654
655 if (*h >= p1.x && *h < p2.x) {
656 ht[t] = p1.y + (*h - p1.x) * (p2.y - p1.y) / (p2.x - p1.x);
657 #ifdef WITH_ASSERT
658 found = true;
659 #endif
660 break;
661 }
662 }
663 assert(found);
664 }
665
666 /* Apply interpolation of curve map results. */
667 *h = (height_t)((ht[corner_a] * yri + ht[corner_b] * yr) * xri + (ht[corner_c] * yri + ht[corner_d] * yr) * xr);
668
669 /* Readd sea level */
670 *h += I2H(1);
671 }
672 }
673 }
674
676 static void HeightMapAdjustWaterLevel(amplitude_t water_percent, height_t h_max_new)
677 {
678 height_t h_min, h_max, h_avg, h_water_level;
679 int64 water_tiles, desired_water_tiles;
680 int *hist;
681
682 HeightMapGetMinMaxAvg(&h_min, &h_max, &h_avg);
683
684 /* Allocate histogram buffer and clear its cells */
685 int *hist_buf = CallocT<int>(h_max - h_min + 1);
686 /* Fill histogram */
687 hist = HeightMapMakeHistogram(h_min, h_max, hist_buf);
688
689 /* How many water tiles do we want? */
690 desired_water_tiles = A2I(((int64)water_percent) * (int64)(_height_map.size_x * _height_map.size_y));
691
692 /* Raise water_level and accumulate values from histogram until we reach required number of water tiles */
693 for (h_water_level = h_min, water_tiles = 0; h_water_level < h_max; h_water_level++) {
694 water_tiles += hist[h_water_level];
695 if (water_tiles >= desired_water_tiles) break;
696 }
697
698 /* We now have the proper water level value.
699 * Transform the height map into new (normalized) height map:
700 * values from range: h_min..h_water_level will become negative so it will be clamped to 0
701 * values from range: h_water_level..h_max are transformed into 0..h_max_new
702 * where h_max_new is depending on terrain type and map size.
703 */
704 for (height_t &h : _height_map.h) {
705 /* Transform height from range h_water_level..h_max into 0..h_max_new range */
706 h = (height_t)(((int)h_max_new) * (h - h_water_level) / (h_max - h_water_level)) + I2H(1);
707 /* Make sure all values are in the proper range (0..h_max_new) */
708 if (h < 0) h = I2H(0);
709 if (h >= h_max_new) h = h_max_new - 1;
710 }
711
712 free(hist_buf);
713 }
714
715 static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime);
716
737 static void HeightMapCoastLines(uint8 water_borders)
738 {
739 int smallest_size = std::min(_settings_game.game_creation.map_x, _settings_game.game_creation.map_y);
740 const int margin = 4;
741 int y, x;
742 double max_x;
743 double max_y;
744
745 /* Lower to sea level */
746 for (y = 0; y <= _height_map.size_y; y++) {
747 if (HasBit(water_borders, BORDER_NE)) {
748 /* Top right */
749 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);
750 max_x = std::max((smallest_size * smallest_size / 64) + max_x, (smallest_size * smallest_size / 64) + margin - max_x);
751 if (smallest_size < 8 && max_x > 5) max_x /= 1.5;
752 for (x = 0; x < max_x; x++) {
753 _height_map.height(x, y) = 0;
754 }
755 }
756
757 if (HasBit(water_borders, BORDER_SW)) {
758 /* Bottom left */
759 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);
760 max_x = std::max((smallest_size * smallest_size / 64) + max_x, (smallest_size * smallest_size / 64) + margin - max_x);
761 if (smallest_size < 8 && max_x > 5) max_x /= 1.5;
762 for (x = _height_map.size_x; x > (_height_map.size_x - 1 - max_x); x--) {
763 _height_map.height(x, y) = 0;
764 }
765 }
766 }
767
768 /* Lower to sea level */
769 for (x = 0; x <= _height_map.size_x; x++) {
770 if (HasBit(water_borders, BORDER_NW)) {
771 /* Top left */
772 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);
773 max_y = std::max((smallest_size * smallest_size / 64) + max_y, (smallest_size * smallest_size / 64) + margin - max_y);
774 if (smallest_size < 8 && max_y > 5) max_y /= 1.5;
775 for (y = 0; y < max_y; y++) {
776 _height_map.height(x, y) = 0;
777 }
778 }
779
780 if (HasBit(water_borders, BORDER_SE)) {
781 /* Bottom right */
782 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);
783 max_y = std::max((smallest_size * smallest_size / 64) + max_y, (smallest_size * smallest_size / 64) + margin - max_y);
784 if (smallest_size < 8 && max_y > 5) max_y /= 1.5;
785 for (y = _height_map.size_y; y > (_height_map.size_y - 1 - max_y); y--) {
786 _height_map.height(x, y) = 0;
787 }
788 }
789 }
790 }
791
793 static void HeightMapSmoothCoastInDirection(int org_x, int org_y, int dir_x, int dir_y)
794 {
795 const int max_coast_dist_from_edge = 35;
796 const int max_coast_Smooth_depth = 35;
797
798 int x, y;
799 int ed; // coast distance from edge
800 int depth;
801
802 height_t h_prev = I2H(1);
803 height_t h;
804
805 assert(IsValidXY(org_x, org_y));
806
807 /* Search for the coast (first non-water tile) */
808 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++) {
809 /* Coast found? */
810 if (_height_map.height(x, y) >= I2H(1)) break;
811
812 /* Coast found in the neighborhood? */
813 if (IsValidXY(x + dir_y, y + dir_x) && _height_map.height(x + dir_y, y + dir_x) > 0) break;
814
815 /* Coast found in the neighborhood on the other side */
816 if (IsValidXY(x - dir_y, y - dir_x) && _height_map.height(x - dir_y, y - dir_x) > 0) break;
817 }
818
819 /* Coast found or max_coast_dist_from_edge has been reached.
820 * Soften the coast slope */
821 for (depth = 0; IsValidXY(x, y) && depth <= max_coast_Smooth_depth; depth++, x += dir_x, y += dir_y) {
822 h = _height_map.height(x, y);
823 h = std::min<uint>(h, h_prev + (4 + depth)); // coast softening formula
824 _height_map.height(x, y) = h;
825 h_prev = h;
826 }
827 }
828
830 static void HeightMapSmoothCoasts(uint8 water_borders)
831 {
832 int x, y;
833 /* First Smooth NW and SE coasts (y close to 0 and y close to size_y) */
834 for (x = 0; x < _height_map.size_x; x++) {
835 if (HasBit(water_borders, BORDER_NW)) HeightMapSmoothCoastInDirection(x, 0, 0, 1);
836 if (HasBit(water_borders, BORDER_SE)) HeightMapSmoothCoastInDirection(x, _height_map.size_y - 1, 0, -1);
837 }
838 /* First Smooth NE and SW coasts (x close to 0 and x close to size_x) */
839 for (y = 0; y < _height_map.size_y; y++) {
840 if (HasBit(water_borders, BORDER_NE)) HeightMapSmoothCoastInDirection(0, y, 1, 0);
841 if (HasBit(water_borders, BORDER_SW)) HeightMapSmoothCoastInDirection(_height_map.size_x - 1, y, -1, 0);
842 }
843 }
844
852 static void HeightMapSmoothSlopes(height_t dh_max)
853 {
854 for (int y = 0; y <= (int)_height_map.size_y; y++) {
855 for (int x = 0; x <= (int)_height_map.size_x; x++) {
856 height_t h_max = std::min(_height_map.height(x > 0 ? x - 1 : x, y), _height_map.height(x, y > 0 ? y - 1 : y)) + dh_max;
857 if (_height_map.height(x, y) > h_max) _height_map.height(x, y) = h_max;
858 }
859 }
860 for (int y = _height_map.size_y; y >= 0; y--) {
861 for (int x = _height_map.size_x; x >= 0; x--) {
862 height_t h_max = std::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;
863 if (_height_map.height(x, y) > h_max) _height_map.height(x, y) = h_max;
864 }
865 }
866 }
867
875 static void HeightMapNormalize()
876 {
877 int sea_level_setting = _settings_game.difficulty.quantity_sea_lakes;
878 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;
879 const height_t h_max_new = TGPGetMaxHeight();
880 const height_t roughness = 7 + 3 * _settings_game.game_creation.tgen_smoothness;
881
882 HeightMapAdjustWaterLevel(water_percent, h_max_new);
883
884 byte water_borders = _settings_game.construction.freeform_edges ? _settings_game.game_creation.water_borders : 0xF;
885 if (water_borders == BORDERS_RANDOM) water_borders = GB(Random(), 0, 4);
886
887 HeightMapCoastLines(water_borders);
888 HeightMapSmoothSlopes(roughness);
889
890 HeightMapSmoothCoasts(water_borders);
891 HeightMapSmoothSlopes(roughness);
892
893 HeightMapSineTransform(I2H(1), h_max_new);
894
895 if (_settings_game.game_creation.variety > 0) {
896 HeightMapCurves(_settings_game.game_creation.variety);
897 }
898
899 HeightMapSmoothSlopes(I2H(1));
900 }
901
909 static double int_noise(const long x, const long y, const int prime)
910 {
911 long n = x + y * prime + _settings_game.game_creation.generation_seed;
912
913 n = (n << 13) ^ n;
914
915 /* Pseudo-random number generator, using several large primes */
916 return 1.0 - (double)((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0;
917 }
918
919
923 static inline double linear_interpolate(const double a, const double b, const double x)
924 {
925 return a + x * (b - a);
926 }
927
928
933 static double interpolated_noise(const double x, const double y, const int prime)
934 {
935 const int integer_X = (int)x;
936 const int integer_Y = (int)y;
937
938 const double fractional_X = x - (double)integer_X;
939 const double fractional_Y = y - (double)integer_Y;
940
941 const double v1 = int_noise(integer_X, integer_Y, prime);
942 const double v2 = int_noise(integer_X + 1, integer_Y, prime);
943 const double v3 = int_noise(integer_X, integer_Y + 1, prime);
944 const double v4 = int_noise(integer_X + 1, integer_Y + 1, prime);
945
946 const double i1 = linear_interpolate(v1, v2, fractional_X);
947 const double i2 = linear_interpolate(v3, v4, fractional_X);
948
949 return linear_interpolate(i1, i2, fractional_Y);
950 }
951
952
959 static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime)
960 {
961 double total = 0.0;
962
963 for (int i = 0; i < 6; i++) {
964 const double frequency = (double)(1 << i);
965 const double amplitude = pow(p, (double)i);
966
967 total += interpolated_noise((x * frequency) / 64.0, (y * frequency) / 64.0, prime) * amplitude;
968 }
969
970 return total;
971 }
972
973
975 static void TgenSetTileHeight(TileIndex tile, int height)
976 {
977 SetTileHeight(tile, height);
978
979 /* Only clear the tiles within the map area. */
980 if (IsInnerTile(tile)) {
981 MakeClear(tile, CLEAR_GRASS, 3);
982 }
983 }
984
992 void GenerateTerrainPerlin()
993 {
994 if (!AllocHeightMap()) return;
995 GenerateWorldSetAbortCallback(FreeHeightMap);
996
997 HeightMapGenerate();
998
999 IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
1000
1001 HeightMapNormalize();
1002
1003 IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
1004
1005 /* First make sure the tiles at the north border are void tiles if needed. */
1006 if (_settings_game.construction.freeform_edges) {
1007 for (uint x = 0; x < MapSizeX(); x++) MakeVoid(TileXY(x, 0));
1008 for (uint y = 0; y < MapSizeY(); y++) MakeVoid(TileXY(0, y));
1009 }
1010
1011 int max_height = H2I(TGPGetMaxHeight());
1012
1013 /* Transfer height map into OTTD map */
1014 for (int y = 0; y < _height_map.size_y; y++) {
1015 for (int x = 0; x < _height_map.size_x; x++) {
1016 TgenSetTileHeight(TileXY(x, y), Clamp(H2I(_height_map.height(x, y)), 0, max_height));
1017 }
1018 }
1019
1020 IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
1021
1022 FreeHeightMap();
1023 GenerateWorldSetAbortCallback(nullptr);
1024 }
MapLogX
static uint MapLogX()
Logarithm of the map size along the X side.
Definition: map_func.h:51
GenerateTerrainPerlin
void GenerateTerrainPerlin()
The main new land generator using Perlin noise.
Definition: tgp.cpp:992
GameCreationSettings::generation_seed
uint32 generation_seed
noise seed for world generation
Definition: settings_type.h:312
AllocHeightMap
static bool AllocHeightMap()
Allocate array of (MapSizeX()+1)*(MapSizeY()+1) heights and init the _height_map structure members.
Definition: tgp.cpp:321
GB
static uint GB(const T x, const uint8 s, const uint8 n)
Fetch n bits from x, started at bit s.
Definition: bitmath_func.hpp:32
landscape_type.h
GameCreationSettings::custom_sea_level
byte custom_sea_level
manually entered percentage of water in the map
Definition: settings_type.h:334
GameCreationSettings::map_y
uint8 map_y
Y size of map.
Definition: settings_type.h:316
GameCreationSettings::landscape
byte landscape
the landscape we're currently in
Definition: settings_type.h:328
GameCreationSettings::tgen_smoothness
byte tgen_smoothness
how rough is the terrain from 0-3
Definition: settings_type.h:323
MIN_MAP_SIZE_BITS
static const uint MIN_MAP_SIZE_BITS
Minimal and maximal map width and height.
Definition: map_type.h:63
A2I
#define A2I(i)
Conversion: amplitude_t to int.
Definition: tgp.cpp:194
ConstructionSettings::map_height_limit
uint8 map_height_limit
the maximum allowed heightlevel
Definition: settings_type.h:342
MakeClear
static void MakeClear(TileIndex t, ClearGround g, uint density)
Make a clear tile.
Definition: clear_map.h:259
HeightMapCurves
static void HeightMapCurves(uint level)
Additional map variety is provided by applying different curve maps to different parts of the map.
Definition: tgp.cpp:547
HeightMapGenerate
static void HeightMapGenerate()
Base Perlin noise generator - fills height map with raw Perlin noise.
Definition: tgp.cpp:360
I2H
#define I2H(i)
Conversion: int to height_t.
Definition: tgp.cpp:187
GameSettings::difficulty
DifficultySettings difficulty
settings related to the difficulty
Definition: settings_type.h:586
HasBit
static bool HasBit(const T x, const uint8 y)
Checks if a bit in a value is set.
Definition: bitmath_func.hpp:103
CLEAR_GRASS
@ CLEAR_GRASS
0-3
Definition: clear_map.h:20
GameCreationSettings::variety
byte variety
variety level applied to TGP
Definition: settings_type.h:332
void_map.h
HeightMap
Height map - allocated array of heights (MapSizeX() + 1) x (MapSizeY() + 1)
Definition: tgp.cpp:162
TileIndex
The index/ID of a Tile.
Definition: tile_type.h:85
HeightMapAdjustWaterLevel
static void HeightMapAdjustWaterLevel(amplitude_t water_percent, height_t h_max_new)
Adjusts heights in height map to contain required amount of water tiles.
Definition: tgp.cpp:676
GetEstimationTGPMapHeight
uint GetEstimationTGPMapHeight()
Get an overestimation of the highest peak TGP wants to generate.
Definition: tgp.cpp:253
RandomRange
static uint32 RandomRange(uint32 limit)
Pick a random number between 0 and limit - 1, inclusive.
Definition: random_func.hpp:81
IsValidXY
static bool IsValidXY(int x, int y)
Check if a X/Y set are within the map.
Definition: tgp.cpp:311
clear_map.h
GetAmplitude
static amplitude_t GetAmplitude(int frequency)
Get the amplitude associated with the currently selected smoothness and maximum height level.
Definition: tgp.cpp:264
linear_interpolate
static double linear_interpolate(const double a, const double b, const double x)
This routine determines the interpolated value between a and b.
Definition: tgp.cpp:923
genworld.h
IncreaseGeneratingWorldProgress
void IncreaseGeneratingWorldProgress(GenWorldProgress cls)
Increases the current stage of the world generation with one.
Definition: genworld_gui.cpp:1572
HeightMapNormalize
static void HeightMapNormalize()
Height map terraform post processing:
Definition: tgp.cpp:875
interpolated_noise
static double interpolated_noise(const double x, const double y, const int prime)
This routine returns the smoothed interpolated noise for an x and y, using the values from the surrou...
Definition: tgp.cpp:933
A2H
#define A2H(a)
Conversion: amplitude_t to height_t.
Definition: tgp.cpp:197
GameSettings::game_creation
GameCreationSettings game_creation
settings used during the creation of a game (map)
Definition: settings_type.h:587
HeightMapCoastLines
static void HeightMapCoastLines(uint8 water_borders)
This routine sculpts in from the edge a random amount, again a Perlin sequence, to avoid the rigid fl...
Definition: tgp.cpp:737
MapSizeX
static uint MapSizeX()
Get the size of the map along the X.
Definition: map_func.h:72
GWP_LANDSCAPE
@ GWP_LANDSCAPE
Create the landscape.
Definition: genworld.h:71
perlin_coast_noise_2D
static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime)
This is a similar function to the main perlin noise calculation, but uses the value p passed as a par...
Definition: tgp.cpp:959
DifficultySettings::terrain_type
byte terrain_type
the mountainousness of the landscape
Definition: settings_type.h:89
height_t
int16 height_t
Fixed point type for heights.
Definition: tgp.cpp:154
_height_map
static HeightMap _height_map
Global height map instance.
Definition: tgp.cpp:184
MAX_TGP_FREQUENCIES
static const int MAX_TGP_FREQUENCIES
Maximum number of TGP noise frequencies.
Definition: tgp.cpp:200
_water_percent
static const amplitude_t _water_percent[4]
Desired water percentage (100% == 1024) - indexed by _settings_game.difficulty.quantity_sea_lakes.
Definition: tgp.cpp:203
H2I
#define H2I(i)
Conversion: height_t to int.
Definition: tgp.cpp:189
HeightMap::height
height_t & height(uint x, uint y)
Height map accessor.
Definition: tgp.cpp:177
GameCreationSettings::water_borders
byte water_borders
bitset of the borders that are water
Definition: settings_type.h:329
RandomHeight
static height_t RandomHeight(amplitude_t rMax)
Generates new random height in given amplitude (generated numbers will range from - amplitude to + am...
Definition: tgp.cpp:347
GenerateWorldSetAbortCallback
void GenerateWorldSetAbortCallback(GWAbortProc *proc)
Set here the function, if any, that you want to be called when landscape generation is aborted.
Definition: genworld.cpp:229
MakeVoid
static void MakeVoid(TileIndex t)
Make a nice void tile ;)
Definition: void_map.h:19
HeightMapSmoothCoasts
static void HeightMapSmoothCoasts(uint8 water_borders)
Smooth coasts by modulating height of tiles close to map edges with cosine of distance from edge.
Definition: tgp.cpp:830
FreeHeightMap
static void FreeHeightMap()
Free height map.
Definition: tgp.cpp:337
HeightMapMakeHistogram
static int * HeightMapMakeHistogram(height_t h_min, height_t h_max, int *hist_buf)
Dill histogram and return pointer to its base point - to the count of zero heights.
Definition: tgp.cpp:443
_settings_game
GameSettings _settings_game
Game settings of a running game or the scenario editor.
Definition: settings.cpp:54
safeguards.h
GameCreationSettings::custom_terrain_type
byte custom_terrain_type
manually entered height for TGP to aim for
Definition: settings_type.h:333
ConstructionSettings::freeform_edges
bool freeform_edges
allow terraforming the tiles at the map edges
Definition: settings_type.h:354
HeightMapSmoothCoastInDirection
static void HeightMapSmoothCoastInDirection(int org_x, int org_y, int dir_x, int dir_y)
Start at given point, move in given direction, find and Smooth coast in that direction.
Definition: tgp.cpp:793
DifficultySettings::quantity_sea_lakes
byte quantity_sea_lakes
the amount of seas/lakes
Definition: settings_type.h:90
MapSizeY
static uint MapSizeY()
Get the size of the map along the Y.
Definition: map_func.h:82
stdafx.h
SetTileHeight
static void SetTileHeight(TileIndex tile, uint height)
Sets the height of a tile.
Definition: tile_map.h:57
Clamp
static T Clamp(const T a, const T min, const T max)
Clamp a value between an interval.
Definition: math_func.hpp:77
MAX_MAP_SIZE_BITS
static const uint MAX_MAP_SIZE_BITS
Maximal size of map is equal to 2 ^ MAX_MAP_SIZE_BITS.
Definition: map_type.h:64
TileXY
static TileIndex TileXY(uint x, uint y)
Returns the TileIndex of a coordinate.
Definition: map_func.h:163
GameCreationSettings::map_x
uint8 map_x
X size of map.
Definition: settings_type.h:315
HeightMapSineTransform
static void HeightMapSineTransform(height_t h_min, height_t h_max)
Applies sine wave redistribution onto height map.
Definition: tgp.cpp:457
CUSTOM_TERRAIN_TYPE_NUMBER_DIFFICULTY
static const uint CUSTOM_TERRAIN_TYPE_NUMBER_DIFFICULTY
Value for custom terrain type in difficulty settings.
Definition: genworld.h:45
HeightMapSmoothSlopes
static void HeightMapSmoothSlopes(height_t dh_max)
This routine provides the essential cleanup necessary before OTTD can display the terrain.
Definition: tgp.cpp:852
abs
static T abs(const T a)
Returns the absolute value of (scalar) variable.
Definition: math_func.hpp:21
lengthof
#define lengthof(x)
Return the length of an fixed size array.
Definition: stdafx.h:386
random_func.hpp
MemSetT
static void MemSetT(T *ptr, byte value, size_t num=1)
Type-safe version of memset().
Definition: mem_func.hpp:49
TgenSetTileHeight
static void TgenSetTileHeight(TileIndex tile, int height)
A small helper function to initialize the terrain.
Definition: tgp.cpp:975
GameSettings::construction
ConstructionSettings construction
construction of things in-game
Definition: settings_type.h:588
HeightMapGetMinMaxAvg
static void HeightMapGetMinMaxAvg(height_t *min_ptr, height_t *max_ptr, height_t *avg_ptr)
Returns min, max and average height from height map.
Definition: tgp.cpp:420
TGPGetMaxHeight
static height_t TGPGetMaxHeight()
Gets the maximum allowed height while generating a map based on mapsize, terraintype,...
Definition: tgp.cpp:211
CUSTOM_SEA_LEVEL_NUMBER_DIFFICULTY
static const uint CUSTOM_SEA_LEVEL_NUMBER_DIFFICULTY
Value for custom sea level in difficulty settings.
Definition: genworld.h:47
free
static void free(const void *ptr)
Version of the standard free that accepts const pointers.
Definition: stdafx.h:470
int_noise
static double int_noise(const long x, const long y, const int prime)
The Perlin Noise calculation using large primes The initial number is adjusted by two values; the gen...
Definition: tgp.cpp:909
IsInnerTile
static bool IsInnerTile(TileIndex tile)
Check if a tile is within the map (not a border)
Definition: tile_map.h:109
MapLogY
static uint MapLogY()
Logarithm of the map size along the y side.
Definition: map_func.h:62
amplitude_t
int amplitude_t
Fixed point array for amplitudes (and percent values)
Definition: tgp.cpp:158
AllocaM
#define AllocaM(T, num_elements)
alloca() has to be called in the parent function, so define AllocaM() as a macro
Definition: alloc_func.hpp:132