OpenTTD
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 
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 
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 */
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 */
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 
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 */
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  */
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 {
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 
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 
888  }
889 
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 
984 {
985  if (!AllocHeightMap()) return;
987 
989 
991 
993 
995 
996  /* First make sure the tiles at the north border are void tiles if needed. */
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 
1012 
1013  FreeHeightMap();
1015 }
#define FOR_ALL_TILES_IN_HEIGHT(h)
Walk through all items of _height_map.h.
Definition: tgp.cpp:204
uint8 max_heightlevel
maximum allowed heightlevel
static uint MapSizeX()
Get the size of the map along the X.
Definition: map_func.h:74
GameSettings _settings_game
Game settings of a running game or the scenario editor.
Definition: settings.cpp:77
static uint MapSizeY()
Get the size of the map along the Y.
Definition: map_func.h:84
static void MakeVoid(TileIndex t)
Make a nice void tile ;)
Definition: void_map.h:21
byte landscape
the landscape we&#39;re currently in
#define I2H(i)
Conversion: int to height_t.
Definition: tgp.cpp:190
static void HeightMapCurves(uint level)
Additional map variety is provided by applying different curve maps to different parts of the map...
Definition: tgp.cpp:539
static void TgenSetTileHeight(TileIndex tile, int height)
A small helper function to initialize the terrain.
Definition: tgp.cpp:966
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:900
static uint MapLogX()
Logarithm of the map size along the X side.
Definition: map_func.h:53
static const uint CUSTOM_SEA_LEVEL_NUMBER_DIFFICULTY
Value for custom sea level in difficulty settings.
Definition: genworld.h:46
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:821
static HeightMap _height_map
Global height map instance.
Definition: tgp.cpp:187
int amplitude_t
Fixed point array for amplitudes (and percent values)
Definition: tgp.cpp:160
DifficultySettings difficulty
settings related to the difficulty
#define A2H(a)
Conversion: amplitude_t to height_t.
Definition: tgp.cpp:200
Functions related to world/map generation.
static height_t TGPGetMaxHeight()
Gets the maximum allowed height while generating a map based on mapsize, terraintype, and the maximum height level.
Definition: tgp.cpp:218
static uint MapLogY()
Logarithm of the map size along the y side.
Definition: map_func.h:64
#define AllocaM(T, num_elements)
alloca() has to be called in the parent function, so define AllocaM() as a macro
Definition: alloc_func.hpp:134
uint8 map_x
X size of map.
static T max(const T a, const T b)
Returns the maximum of two values.
Definition: math_func.hpp:26
byte custom_sea_level
manually entered percentage of water in the map
static uint32 RandomRange(uint32 limit)
Pick a random number between 0 and limit - 1, inclusive.
Definition: random_func.hpp:83
Pseudo random number generator.
uint8 map_y
Y size of map.
void GenerateWorldSetAbortCallback(GWAbortProc *proc)
Set here the function, if any, that you want to be called when landscape generation is aborted...
Definition: genworld.cpp:233
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:409
static void SetTileHeight(TileIndex tile, uint height)
Sets the height of a tile.
Definition: tile_map.h:49
bool freeform_edges
allow terraforming the tiles at the map edges
byte tgen_smoothness
how rough is the terrain from 0-3
Height map - allocated array of heights (MapSizeX() + 1) x (MapSizeY() + 1)
Definition: tgp.cpp:164
Create the landscape.
Definition: genworld.h:70
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:728
static void HeightMapNormalize()
Height map terraform post processing:
Definition: tgp.cpp:866
static const int MAX_TGP_FREQUENCIES
Maximum number of TGP noise frequencies.
Definition: tgp.cpp:207
byte water_borders
bitset of the borders that are water
static bool AllocHeightMap()
Allocate array of (MapSizeX()+1)*(MapSizeY()+1) heights and init the _height_map structure members...
Definition: tgp.cpp:306
int16 height_t
Fixed point type for heights.
Definition: tgp.cpp:156
#define H2I(i)
Conversion: height_t to int.
Definition: tgp.cpp:192
Definition of base types and functions in a cross-platform compatible way.
A number of safeguards to prevent using unsafe methods.
static void HeightMapGenerate()
Base Perlin noise generator - fills height map with raw Perlin noise.
Definition: tgp.cpp:349
#define A2I(i)
Conversion: amplitude_t to int.
Definition: tgp.cpp:197
void GenerateTerrainPerlin()
The main new land generator using Perlin noise.
Definition: tgp.cpp:983
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:914
#define lengthof(x)
Return the length of an fixed size array.
Definition: depend.cpp:42
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:666
static T min(const T a, const T b)
Returns the minimum of two values.
Definition: math_func.hpp:42
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:784
static void HeightMapSineTransform(height_t h_min, height_t h_max)
Applies sine wave redistribution onto height map.
Definition: tgp.cpp:447
height_t & height(uint x, uint y)
Height map accessor.
Definition: tgp.cpp:180
byte variety
variety level applied to TGP
static amplitude_t GetAmplitude(int frequency)
Get the amplitude associated with the currently selected smoothness and maximum height level...
Definition: tgp.cpp:249
static T Clamp(const T a, const T min, const T max)
Clamp a value between an interval.
Definition: math_func.hpp:139
byte quantity_sea_lakes
the amount of seas/lakes
Definition: settings_type.h:67
uint32 generation_seed
noise seed for world generation
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:336
static const amplitude_t _water_percent[4]
Desired water percentage (100% == 1024) - indexed by _settings_game.difficulty.quantity_sea_lakes.
Definition: tgp.cpp:210
Types related to the landscape.
uint32 TileIndex
The index/ID of a Tile.
Definition: tile_type.h:80
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:950
Map accessors for &#39;clear&#39; tiles.
Map accessors for void tiles.
static bool IsValidXY(int x, int y)
Check if a X/Y set are within the map.
Definition: tgp.cpp:296
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:924
static void MakeClear(TileIndex t, ClearGround g, uint density)
Make a clear tile.
Definition: clear_map.h:261
static T abs(const T a)
Returns the absolute value of (scalar) variable.
Definition: math_func.hpp:83
static uint GB(const T x, const uint8 s, const uint8 n)
Fetch n bits from x, started at bit s.
static void FreeHeightMap()
Free height map.
Definition: tgp.cpp:325
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:432
byte terrain_type
the mountainousness of the landscape
Definition: settings_type.h:66
ConstructionSettings construction
construction of things in-game
static void free(const void *ptr)
Version of the standard free that accepts const pointers.
Definition: depend.cpp:114
static void HeightMapSmoothSlopes(height_t dh_max)
This routine provides the essential cleanup necessary before OTTD can display the terrain...
Definition: tgp.cpp:843
static const uint MAX_MAP_SIZE_BITS
Maximal size of map is equal to 2 ^ MAX_MAP_SIZE_BITS.
Definition: map_type.h:65
static bool HasBit(const T x, const uint8 y)
Checks if a bit in a value is set.
static bool IsInnerTile(TileIndex tile)
Check if a tile is within the map (not a border)
Definition: tile_map.h:102
GameCreationSettings game_creation
settings used during the creation of a game (map)
void IncreaseGeneratingWorldProgress(GenWorldProgress cls)
Increases the current stage of the world generation with one.
static TileIndex TileXY(uint x, uint y)
Returns the TileIndex of a coordinate.
Definition: map_func.h:165
static const uint MIN_MAP_SIZE_BITS
Minimal and maximal map width and height.
Definition: map_type.h:64
static void MemSetT(T *ptr, byte value, size_t num=1)
Type-safe version of memset().
Definition: mem_func.hpp:51