diff options
Diffstat (limited to 'src/tgp.cpp')
| -rw-r--r-- | src/tgp.cpp | 829 |
1 files changed, 829 insertions, 0 deletions
diff --git a/src/tgp.cpp b/src/tgp.cpp new file mode 100644 index 000000000..d7f9722f9 --- /dev/null +++ b/src/tgp.cpp @@ -0,0 +1,829 @@ +/* $Id$ */ + +#include "stdafx.h" +#include <math.h> +#include "openttd.h" +#include "clear_map.h" +#include "functions.h" +#include "map.h" +#include "table/strings.h" +#include "clear_map.h" +#include "tile.h" +#include "variables.h" +#include "void_map.h" +#include "tgp.h" +#include "console.h" +#include "genworld.h" + +/* + * OTTD Perlin Noise Landscape Generator, aka TerraGenesis Perlin + * + * Quickie guide to Perlin Noise + * Perlin noise is a predictable pseudo random number sequence. By generating + * it in 2 dimensions, it becomes a useful random map, that for a given seed + * and starting X & Y is entirely predictable. On the face of it, that may not + * be useful. However, it means that if you want to replay a map in a different + * terrain, or just vary the sea level, you just re-run the generator with the + * same seed. The seed is an int32, and is randomised on each run of New Game. + * The Scenario Generator does not randomise the value, so that you can + * experiment with one terrain until you are happy, or click "Random" for a new + * random seed. + * + * Perlin Noise is a series of "octaves" of random noise added together. By + * reducing the amplitude of the noise with each octave, the first octave of + * noise defines the main terrain sweep, the next the ripples on that, and the + * next the ripples on that. I use 6 octaves, with the amplitude controlled by + * a power ratio, usually known as a persistence or p value. This I vary by the + * smoothness selection, as can be seen in the table below. The closer to 1, + * the more of that octave is added. Each octave is however raised to the power + * of its position in the list, so the last entry in the "smooth" row, 0.35, is + * raised to the power of 6, so can only add 0.001838... of the amplitude to + * the running total. + * + * In other words; the first p value sets the general shape of the terrain, the + * second sets the major variations to that, ... until finally the smallest + * bumps are added. + * + * Usefully, this routine is totally scaleable; so when 32bpp comes along, the + * terrain can be as bumpy as you like! It is also infinitely expandable; a + * single random seed terrain continues in X & Y as far as you care to + * calculate. In theory, we could use just one seed value, but randomly select + * where in the Perlin XY space we use for the terrain. Personally I prefer + * using a simple (0, 0) to (X, Y), with a varying seed. + * + * + * Other things i have had to do: mountainous wasnt mountainous enough, and + * since we only have 0..15 heights available, I add a second generated map + * (with a modified seed), onto the original. This generally raises the + * terrain, which then needs scaling back down. Overall effect is a general + * uplift. + * + * However, the values on the top of mountains are then almost guaranteed to go + * too high, so large flat plateaus appeared at height 15. To counter this, I + * scale all heights above 12 to proportion up to 15. It still makes the + * mountains have flatish tops, rather than craggy peaks, but at least they + * arent smooth as glass. + * + * + * For a full discussion of Perlin Noise, please visit: + * http://freespace.virgin.net/hugo.elias/models/m_perlin.htm + * + * + * Evolution II + * + * The algorithm as described in the above link suggests to compute each tile height + * as composition of several noise waves. Some of them are computed directly by + * noise(x, y) function, some are calculated using linear approximation. Our + * first implementation of perlin_noise_2D() used 4 noise(x, y) calls plus + * 3 linear interpolations. It was called 6 times for each tile. This was a bit + * CPU expensive. + * + * The following implementation uses optimized algorithm that should produce + * the same quality result with much less computations, but more memory accesses. + * The overal speedup should be 300% to 800% depending on CPU and memory speed. + * + * I will try to explain it on the example below: + * + * Have a map of 4 x 4 tiles, our simplifiead noise generator produces only two + * values -1 and +1, use 3 octaves with wave lenght 1, 2 and 4, with amplitudes + * 3, 2, 1. Original algorithm produces: + * + * 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 + * 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 + * 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 + * 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 + * + * 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 + * 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 + * 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 + * 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 + * + * + * Optimization 1: + * + * 1) we need to allocate a bit more tiles: (size_x + 1) * (size_y + 1) = (5 * 5): + * + * 2) setup corner values using amplitude 3 + * { -3.0 X X X 3.0 } + * { X X X X X } + * { X X X X X } + * { X X X X X } + * { 3.0 X X X -3.0 } + * + * 3a) interpolate values in the middle + * { -3.0 X 0.0 X 3.0 } + * { X X X X X } + * { 0.0 X 0.0 X 0.0 } + * { X X X X X } + * { 3.0 X 0.0 X -3.0 } + * + * 3b) add patches with amplitude 2 to them + * { -5.0 X 2.0 X 1.0 } + * { X X X X X } + * { 2.0 X -2.0 X 2.0 } + * { X X X X X } + * { 1.0 X 2.0 X -5.0 } + * + * 4a) interpolate values in the middle + * { -5.0 -1.5 2.0 1.5 1.0 } + * { -1.5 -0.75 0.0 0.75 1.5 } + * { 2.0 0.0 -2.0 0.0 2.0 } + * { 1.5 0.75 0.0 -0.75 -1.5 } + * { 1.0 1.5 2.0 -1.5 -5.0 } + * + * 4b) add patches with amplitude 1 to them + * { -6.0 -0.5 1.0 2.5 0.0 } + * { -0.5 -1.75 1.0 -0.25 2.5 } + * { 1.0 1.0 -3.0 1.0 1.0 } + * { 2.5 -0.25 1.0 -1.75 -0.5 } + * { 0.0 2.5 1.0 -0.5 -6.0 } + * + * + * + * Optimization 2: + * + * As you can see above, each noise function was called just once. Therefore + * we don't need to use noise function that calculates the noise from x, y and + * some prime. The same quality result we can obtain using standard Random() + * function instead. + * + */ + +#ifndef M_PI_2 +#define M_PI_2 1.57079632679489661923 +#define M_PI 3.14159265358979323846 +#endif /* M_PI_2 */ + +/** Fixed point type for heights */ +typedef int16 height_t; +static const int height_decimal_bits = 4; +static const height_t _invalid_height = -32768; + +/** Fixed point array for amplitudes (and percent values) */ +typedef int amplitude_t; +static const int amplitude_decimal_bits = 10; + +/** Height map - allocated array of heights (MapSizeX() + 1) x (MapSizeY() + 1) */ +typedef struct HeightMap +{ + height_t *h; //! array of heights + uint dim_x; //! height map size_x MapSizeX() + 1 + uint total_size; //! height map total size + uint size_x; //! MapSizeX() + uint size_y; //! MapSizeY() +} HeightMap; + +/** Global height map instance */ +static HeightMap _height_map = {NULL, 0, 0, 0, 0}; + +/** Height map accessors */ +#define HeightMapXY(x, y) _height_map.h[(x) + (y) * _height_map.dim_x] + +/** Conversion: int to height_t */ +#define I2H(i) ((i) << height_decimal_bits) +/** Conversion: height_t to int */ +#define H2I(i) ((i) >> height_decimal_bits) + +/** Conversion: int to amplitude_t */ +#define I2A(i) ((i) << amplitude_decimal_bits) +/** Conversion: amplitude_t to int */ +#define A2I(i) ((i) >> amplitude_decimal_bits) + +/** Conversion: amplitude_t to height_t */ +#define A2H(a) ((height_decimal_bits < amplitude_decimal_bits) \ + ? ((a) >> (amplitude_decimal_bits - height_decimal_bits)) \ + : ((a) << (height_decimal_bits - amplitude_decimal_bits))) + +/** Walk through all items of _height_map.h */ +#define FOR_ALL_TILES_IN_HEIGHT(h) for (h = _height_map.h; h < &_height_map.h[_height_map.total_size]; h++) + +/** Noise amplitudes (multiplied by 1024) + * - indexed by "smoothness setting" and log2(frequency) */ +static const amplitude_t _amplitudes_by_smoothness_and_frequency[4][12] = { + // Very smooth + {1000, 350, 123, 43, 15, 1, 1, 0, 0, 0, 0, 0}, + // Smooth + {1000, 1000, 403, 200, 64, 8, 1, 0, 0, 0, 0, 0}, + // Rough + {1000, 1200, 800, 500, 200, 16, 4, 0, 0, 0, 0, 0}, + // Very Rough + {1500, 1000, 1200, 1000, 500, 32, 20, 0, 0, 0, 0, 0}, +}; + +/** Desired water percentage (100% == 1024) - indexed by _opt.diff.quantity_sea_lakes */ +static const amplitude_t _water_percent[4] = {20, 80, 250, 400}; + +/** Desired maximum height - indexed by _opt.diff.terrain_type */ +static const int8 _max_height[4] = { + 6, // Very flat + 9, // Flat + 12, // Hilly + 15 // Mountainous +}; + +/** Check if a X/Y set are within the map. */ +static inline bool IsValidXY(uint x, uint y) +{ + return ((int)x) >= 0 && x < _height_map.size_x && ((int)y) >= 0 && y < _height_map.size_y; +} + + +/** Allocate array of (MapSizeX()+1)*(MapSizeY()+1) heights and init the _height_map structure members */ +static inline bool AllocHeightMap(void) +{ + height_t *h; + + _height_map.size_x = MapSizeX(); + _height_map.size_y = MapSizeY(); + + /* Allocate memory block for height map row pointers */ + _height_map.total_size = (_height_map.size_x + 1) * (_height_map.size_y + 1); + _height_map.dim_x = _height_map.size_x + 1; + _height_map.h = calloc(_height_map.total_size, sizeof(*_height_map.h)); + if (_height_map.h == NULL) return false; + + /* Iterate through height map initialize values */ + FOR_ALL_TILES_IN_HEIGHT(h) *h = _invalid_height; + + return true; +} + +/** Free height map */ +static inline void FreeHeightMap(void) +{ + if (_height_map.h == NULL) return; + free(_height_map.h); + _height_map.h = NULL; +} + +/** RandomHeight() generator */ +static inline height_t RandomHeight(amplitude_t rMax) +{ + amplitude_t ra = (Random() << 16) | (Random() & 0x0000FFFF); + height_t rh; + /* Scale the amplitude for better resolution */ + rMax *= 16; + /* Spread height into range -rMax..+rMax */ + rh = A2H(ra % (2 * rMax + 1) - rMax); + return rh; +} + +/** One interpolation and noise round */ +static bool ApplyNoise(uint log_frequency, amplitude_t amplitude) +{ + uint size_min = min(_height_map.size_x, _height_map.size_y); + uint step = size_min >> log_frequency; + uint x, y; + + assert(_height_map.h != NULL); + + /* Are we finished? */ + if (step == 0) return false; + + if (log_frequency == 0) { + /* This is first round, we need to establish base heights with step = size_min */ + for (y = 0; y <= _height_map.size_y; y += step) { + for (x = 0; x <= _height_map.size_x; x += step) { + height_t height = (amplitude > 0) ? RandomHeight(amplitude) : 0; + HeightMapXY(x, y) = height; + } + } + return true; + } + + /* It is regular iteration round. + * Interpolate height values at odd x, even y tiles */ + for (y = 0; y <= _height_map.size_y; y += 2 * step) { + for (x = 0; x < _height_map.size_x; x += 2 * step) { + height_t h00 = HeightMapXY(x + 0 * step, y); + height_t h02 = HeightMapXY(x + 2 * step, y); + height_t h01 = (h00 + h02) / 2; + HeightMapXY(x + 1 * step, y) = h01; + } + } + + /* Interpolate height values at odd y tiles */ + for (y = 0; y < _height_map.size_y; y += 2 * step) { + for (x = 0; x <= _height_map.size_x; x += step) { + height_t h00 = HeightMapXY(x, y + 0 * step); + height_t h20 = HeightMapXY(x, y + 2 * step); + height_t h10 = (h00 + h20) / 2; + HeightMapXY(x, y + 1 * step) = h10; + } + } + + for (y = 0; y <= _height_map.size_y; y += step) { + for (x = 0; x <= _height_map.size_x; x += step) { + HeightMapXY(x, y) += RandomHeight(amplitude); + } + } + return (step > 1); +} + +/** Base Perlin noise generator - fills height map with raw Perlin noise */ +static void HeightMapGenerate(void) +{ + uint size_min = min(_height_map.size_x, _height_map.size_y); + uint iteration_round = 0; + amplitude_t amplitude; + bool continue_iteration; + uint log_size_min, log_frequency_min; + int log_frequency; + + /* Find first power of two that fits */ + for (log_size_min = 6; (1U << log_size_min) < size_min; log_size_min++) { } + log_frequency_min = log_size_min - 6; + + do { + log_frequency = iteration_round - log_frequency_min; + if (log_frequency >= 0) { + amplitude = _amplitudes_by_smoothness_and_frequency[_patches.tgen_smoothness][log_frequency]; + } else { + amplitude = 0; + } + continue_iteration = ApplyNoise(iteration_round, amplitude); + iteration_round++; + } while(continue_iteration); +} + +/** Returns min, max and average height from height map */ +static void HeightMapGetMinMaxAvg(height_t *min_ptr, height_t *max_ptr, height_t *avg_ptr) +{ + height_t h_min, h_max, h_avg, *h; + int64 h_accu = 0; + h_min = h_max = HeightMapXY(0, 0); + + /* Get h_min, h_max and accumulate heights into h_accu */ + FOR_ALL_TILES_IN_HEIGHT(h) { + if (*h < h_min) h_min = *h; + if (*h > h_max) h_max = *h; + h_accu += *h; + } + + /* Get average height */ + h_avg = (height_t)(h_accu / (_height_map.size_x * _height_map.size_y)); + + /* Return required results */ + if (min_ptr != NULL) *min_ptr = h_min; + if (max_ptr != NULL) *max_ptr = h_max; + if (avg_ptr != NULL) *avg_ptr = h_avg; +} + +/** Dill histogram and return pointer to its base point - to the count of zero heights */ +static int *HeightMapMakeHistogram(height_t h_min, height_t h_max, int *hist_buf) +{ + int *hist = hist_buf - h_min; + height_t *h; + + /* Fill histogram */ + FOR_ALL_TILES_IN_HEIGHT(h) { + assert(*h >= h_min); + assert(*h <= h_max); + hist[*h]++; + } + return hist; +} + +/** Applies sine wave redistribution onto height map */ +static void HeightMapSineTransform(height_t h_min, height_t h_max) +{ + height_t *h; + + FOR_ALL_TILES_IN_HEIGHT(h) { + double fheight; + + if (*h < h_min) continue; + + /* Transform height into 0..1 space */ + fheight = (double)(*h - h_min) / (double)(h_max - h_min); + /* Apply sine transform depending on landscape type */ + switch(_opt.landscape) { + case LT_CANDY: + case LT_NORMAL: + /* Move and scale 0..1 into -1..+1 */ + fheight = 2 * fheight - 1; + /* Sine transform */ + fheight = sin(fheight * M_PI_2); + /* Transform it back from -1..1 into 0..1 space */ + fheight = 0.5 * (fheight + 1); + break; + + case LT_HILLY: + { + /* Arctic terrain needs special height distribution. + * Redistribute heights to have more tiles at highest (75%..100%) range */ + double sine_upper_limit = 0.75; + double linear_compression = 2; + if (fheight >= sine_upper_limit) { + /* Over the limit we do linear compression up */ + fheight = 1.0 - (1.0 - fheight) / linear_compression; + } else { + double m = 1.0 - (1.0 - sine_upper_limit) / linear_compression; + /* Get 0..sine_upper_limit into -1..1 */ + fheight = 2.0 * fheight / sine_upper_limit - 1.0; + /* Sine wave transform */ + fheight = sin(fheight * M_PI_2); + /* Get -1..1 back to 0..(1 - (1 - sine_upper_limit) / linear_compression) == 0.0..m */ + fheight = 0.5 * (fheight + 1.0) * m; + } + } + break; + + case LT_DESERT: + { + /* Desert terrain needs special height distribution. + * Half of tiles should be at lowest (0..25%) heights */ + double sine_lower_limit = 0.5; + double linear_compression = 2; + if (fheight <= sine_lower_limit) { + /* Under the limit we do linear compression down */ + fheight = fheight / linear_compression; + } else { + double m = sine_lower_limit / linear_compression; + /* Get sine_lower_limit..1 into -1..1 */ + fheight = 2.0 * ((fheight - sine_lower_limit) / (1.0 - sine_lower_limit)) - 1.0; + /* Sine wave transform */ + fheight = sin(fheight * M_PI_2); + /* Get -1..1 back to (sine_lower_limit / linear_compression)..1.0 */ + fheight = 0.5 * ((1.0 - m) * fheight + (1.0 + m)); + } + } + break; + + default: + NOT_REACHED(); + break; + } + /* Transform it back into h_min..h_max space */ + *h = fheight * (h_max - h_min) + h_min; + if (*h < 0) *h = I2H(0); + if (*h >= h_max) *h = h_max - 1; + } +} + +/** Adjusts heights in height map to contain required amount of water tiles */ +static void HeightMapAdjustWaterLevel(amplitude_t water_percent, height_t h_max_new) +{ + height_t h_min, h_max, h_avg, h_water_level; + int water_tiles, desired_water_tiles; + height_t *h; + int *hist_buf, *hist; + + HeightMapGetMinMaxAvg(&h_min, &h_max, &h_avg); + + /* Allocate histogram buffer and clear its cells */ + hist_buf = calloc(h_max - h_min + 1, sizeof(*hist_buf)); + /* Fill histogram */ + hist = HeightMapMakeHistogram(h_min, h_max, hist_buf); + + /* How many water tiles do we want? */ + desired_water_tiles = (int)(((int64)water_percent) * (int64)(_height_map.size_x * _height_map.size_y)) >> amplitude_decimal_bits; + + /* Raise water_level and accumulate values from histogram until we reach required number of water tiles */ + for (h_water_level = h_min, water_tiles = 0; h_water_level < h_max; h_water_level++) { + water_tiles += hist[h_water_level]; + if (water_tiles >= desired_water_tiles) break; + } + + /* We now have the proper water level value. + * Transform the height map into new (normalized) height map: + * values from range: h_min..h_water_level will become negative so it will be clamped to 0 + * values from range: h_water_level..h_max are transformed into 0..h_max_new + * , where h_max_new is 4, 8, 12 or 16 depending on terrain type (very flat, flat, hilly, mountains) + */ + FOR_ALL_TILES_IN_HEIGHT(h) { + /* Transform height from range h_water_level..h_max into 0..h_max_new range */ + *h = (height_t)(((int)h_max_new) * (*h - h_water_level) / (h_max - h_water_level)) + I2H(1); + /* Make sure all values are in the proper range (0..h_max_new) */ + if (*h < 0) *h = I2H(0); + if (*h >= h_max_new) *h = h_max_new - 1; + } + + free(hist_buf); +} + +static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime); + +/** + * This routine sculpts in from the edge a random amount, again a Perlin + * sequence, to avoid the rigid flat-edge slopes that were present before. The + * Perlin noise map doesnt know where we are going to slice across, and so we + * often cut straight through high terrain. the smoothing routine makes it + * legal, gradually increasing up from the edge to the original terrain height. + * By cutting parts of this away, it gives a far more irregular edge to the + * map-edge. Sometimes it works beautifully with the existing sea & lakes, and + * creates a very realistic coastline. Other times the variation is less, and + * the map-edge shows its cliff-like roots. + * + * This routine may be extended to randomly sculpt the height of the terrain + * near the edge. This will have the coast edge at low level (1-3), rising in + * smoothed steps inland to about 15 tiles in. This should make it look as + * though the map has been built for the map size, rather than a slice through + * a larger map. + * + * Please note that all the small numbers; 53, 101, 167, etc. are small primes + * to help give the perlin noise a bit more of a random feel. + */ +static void HeightMapCoastLines(void) +{ + int smallest_size = min(_patches.map_x, _patches.map_y); + const int margin = 4; + uint y, x; + uint max_x; + uint max_y; + + /* Lower to sea level */ + for (y = 0; y <= _height_map.size_y; y++) { + /* Top right */ + max_x = myabs((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); + max_x = max((smallest_size * smallest_size / 16) + max_x, (smallest_size * smallest_size / 16) + margin - max_x); + if (smallest_size < 8 && max_x > 5) max_x /= 1.5; + for (x = 0; x < max_x; x++) { + HeightMapXY(x, y) = 0; + } + + /* Bottom left */ + max_x = myabs((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); + max_x = max((smallest_size * smallest_size / 16) + max_x, (smallest_size * smallest_size / 16) + margin - max_x); + if (smallest_size < 8 && max_x > 5) max_x /= 1.5; + for (x = _height_map.size_x; x > (_height_map.size_x - 1 - max_x); x--) { + HeightMapXY(x, y) = 0; + } + } + + /* Lower to sea level */ + for (x = 0; x <= _height_map.size_x; x++) { + /* Top left */ + max_y = myabs((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); + max_y = max((smallest_size * smallest_size / 16) + max_y, (smallest_size * smallest_size / 16) + margin - max_y); + if (smallest_size < 8 && max_y > 5) max_y /= 1.5; + for (y = 0; y < max_y; y++) { + HeightMapXY(x, y) = 0; + } + + + /* Bottom right */ + max_y = myabs((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); + max_y = max((smallest_size * smallest_size / 16) + max_y, (smallest_size * smallest_size / 16) + margin - max_y); + if (smallest_size < 8 && max_y > 5) max_y /= 1.5; + for (y = _height_map.size_y; y > (_height_map.size_y - 1 - max_y); y--) { + HeightMapXY(x, y) = 0; + } + } +} + +/** Start at given point, move in given direction, find and Smooth coast in that direction */ +static void HeightMapSmoothCoastInDirection(int org_x, int org_y, int dir_x, int dir_y) +{ + const int max_coast_dist_from_edge = 35; + const int max_coast_Smooth_depth = 35; + + int x, y; + int ed; // coast distance from edge + int depth; + + height_t h_prev = 16; + height_t h; + + assert(IsValidXY(org_x, org_y)); + + /* Search for the coast (first non-water tile) */ + 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++) { + /* Coast found? */ + if (HeightMapXY(x, y) > 15) break; + + /* Coast found in the neighborhood? */ + if (IsValidXY(x + dir_y, y + dir_x) && HeightMapXY(x + dir_y, y + dir_x) > 0) break; + + /* Coast found in the neighborhood on the other side */ + if (IsValidXY(x - dir_y, y - dir_x) && HeightMapXY(x - dir_y, y - dir_x) > 0) break; + } + + /* Coast found or max_coast_dist_from_edge has been reached. + * Soften the coast slope */ + for (depth = 0; IsValidXY(x, y) && depth <= max_coast_Smooth_depth; depth++, x += dir_x, y += dir_y) { + h = HeightMapXY(x, y); + h = min(h, h_prev + (4 + depth)); // coast softening formula + HeightMapXY(x, y) = h; + h_prev = h; + } +} + +/** Smooth coasts by modulating height of tiles close to map edges with cosine of distance from edge */ +static void HeightMapSmoothCoasts(void) +{ + uint x, y; + /* First Smooth NW and SE coasts (y close to 0 and y close to size_y) */ + for (x = 0; x < _height_map.size_x; x++) { + HeightMapSmoothCoastInDirection(x, 0, 0, 1); + HeightMapSmoothCoastInDirection(x, _height_map.size_y - 1, 0, -1); + } + /* First Smooth NE and SW coasts (x close to 0 and x close to size_x) */ + for (y = 0; y < _height_map.size_y; y++) { + HeightMapSmoothCoastInDirection(0, y, 1, 0); + HeightMapSmoothCoastInDirection(_height_map.size_x - 1, y, -1, 0); + } +} + +/** + * This routine provides the essential cleanup necessary before OTTD can + * display the terrain. When generated, the terrain heights can jump more than + * one level between tiles. This routine smooths out those differences so that + * the most it can change is one level. When OTTD can support cliffs, this + * routine may not be necessary. + */ +static void HeightMapSmoothSlopes(height_t dh_max) +{ + int x, y; + for (y = 1; y <= (int)_height_map.size_y; y++) { + for (x = 1; x <= (int)_height_map.size_x; x++) { + height_t h_max = min(HeightMapXY(x - 1, y), HeightMapXY(x, y - 1)) + dh_max; + if (HeightMapXY(x, y) > h_max) HeightMapXY(x, y) = h_max; + } + } + for (y = _height_map.size_y - 1; y >= 0; y--) { + for (x = _height_map.size_x - 1; x >= 0; x--) { + height_t h_max = min(HeightMapXY(x + 1, y), HeightMapXY(x, y + 1)) + dh_max; + if (HeightMapXY(x, y) > h_max) HeightMapXY(x, y) = h_max; + } + } +} + +/** Height map terraform post processing: + * - water level adjusting + * - coast Smoothing + * - slope Smoothing + * - height histogram redistribution by sine wave transform */ +static void HeightMapNormalize(void) +{ + const amplitude_t water_percent = _water_percent[_opt.diff.quantity_sea_lakes]; + const height_t h_max_new = I2H(_max_height[_opt.diff.terrain_type]); + const height_t roughness = 7 + 3 * _patches.tgen_smoothness; + + HeightMapAdjustWaterLevel(water_percent, h_max_new); + + HeightMapCoastLines(); + HeightMapSmoothSlopes(roughness); + + HeightMapSmoothCoasts(); + HeightMapSmoothSlopes(roughness); + + HeightMapSineTransform(12, h_max_new); + HeightMapSmoothSlopes(16); +} + +static inline int perlin_landXY(uint x, uint y) +{ + return HeightMapXY(x, y); +} + + +/* The following decimals are the octave power modifiers for the Perlin noise */ +static const double _perlin_p_values[][7] = { // perlin frequency per power + { 0.35, 0.35, 0.35, 0.35, 0.35, 0.25, 0.539 }, // Very smooth + { 0.45, 0.55, 0.45, 0.45, 0.35, 0.25, 0.89 }, // Smooth + { 0.85, 0.80, 0.70, 0.45, 0.45, 0.35, 1.825 }, // Rough 1.825 + { 0.95, 0.85, 0.80, 0.55, 0.55, 0.45, 2.245 } // Very Rough 2.25 +}; + +/** + * The Perlin Noise calculation using large primes + * The initial number is adjusted by two values; the generation_seed, and the + * passed parameter; prime. + * prime is used to allow the perlin noise generator to create useful random + * numbers from slightly different series. + */ +static double int_noise(const long x, const long y, const int prime) +{ + long n = x + y * prime + _patches.generation_seed; + + n = (n << 13) ^ n; + + /* Pseudo-random number generator, using several large primes */ + return 1.0 - (double)((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0; +} + + +/** + * Hj. Malthaner's routine included 2 different noise smoothing methods. + * We now use the "raw" int_noise one. + * However, it may be useful to move to the other routine in future. + * So it is included too. + */ +static double smoothed_noise(const int x, const int y, const int prime) +{ +#if 0 + /* A hilly world (four corner smooth) */ + const double sides = int_noise(x - 1, y) + int_noise(x + 1, y) + int_noise(x, y - 1) + int_noise(x, y + 1); + const double center = int_noise(x, y); + return (sides + sides + center * 4) / 8.0; +#endif + + /* This gives very hilly world */ + return int_noise(x, y, prime); +} + + +/** + * This routine determines the interpolated value between a and b + */ +static inline double linear_interpolate(const double a, const double b, const double x) +{ + return a + x * (b - a); +} + + +/** + * This routine returns the smoothed interpolated noise for an x and y, using + * the values from the surrounding positions. + */ +static double interpolated_noise(const double x, const double y, const int prime) +{ + const int integer_X = (int)x; + const int integer_Y = (int)y; + + const double fractional_X = x - (double)integer_X; + const double fractional_Y = y - (double)integer_Y; + + const double v1 = smoothed_noise(integer_X, integer_Y, prime); + const double v2 = smoothed_noise(integer_X + 1, integer_Y, prime); + const double v3 = smoothed_noise(integer_X, integer_Y + 1, prime); + const double v4 = smoothed_noise(integer_X + 1, integer_Y + 1, prime); + + const double i1 = linear_interpolate(v1, v2, fractional_X); + const double i2 = linear_interpolate(v3, v4, fractional_X); + + return linear_interpolate(i1, i2, fractional_Y); +} + + +/** + * This is a similar function to the main perlin noise calculation, but uses + * the value p passed as a parameter rather than selected from the predefined + * sequences. as you can guess by its title, i use this to create the indented + * coastline, which is just another perlin sequence. + */ +static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime) +{ + double total = 0.0; + int i; + + for (i = 0; i < 6; i++) { + const double frequency = (double)(1 << i); + const double amplitude = pow(p, (double)i); + + total += interpolated_noise((x * frequency) / 64.0, (y * frequency) / 64.0, prime) * amplitude; + } + + return total; +} + + +/** A small helper function */ +static void TgenSetTileHeight(TileIndex tile, int height) +{ + SetTileHeight(tile, height); + MakeClear(tile, CLEAR_GRASS, 3); +} + +/** + * The main new land generator using Perlin noise. Desert landscape is handled + * different to all others to give a desert valley between two high mountains. + * Clearly if a low height terrain (flat/very flat) is chosen, then the tropic + * areas wont be high enough, and there will be very little tropic on the map. + * Thus Tropic works best on Hilly or Mountainous. + */ +void GenerateTerrainPerlin(void) +{ + uint x, y; + + if (!AllocHeightMap()) return; + GenerateWorldSetAbortCallback(FreeHeightMap); + + HeightMapGenerate(); + + IncreaseGeneratingWorldProgress(GWP_LANDSCAPE); + + HeightMapNormalize(); + + IncreaseGeneratingWorldProgress(GWP_LANDSCAPE); + + /* Transfer height map into OTTD map */ + for (y = 2; y < _height_map.size_y - 2; y++) { + for (x = 2; x < _height_map.size_x - 2; x++) { + int height = H2I(HeightMapXY(x, y)); + if (height < 0) height = 0; + if (height > 15) height = 15; + TgenSetTileHeight(TileXY(x, y), height); + } + } + + IncreaseGeneratingWorldProgress(GWP_LANDSCAPE); + + /* Recreate void tiles at the border in case they have been affected by generation */ + for (y = 0; y < _height_map.size_y - 1; y++) MakeVoid(_height_map.size_x * y + _height_map.size_x - 1); + for (x = 0; x < _height_map.size_x; x++) MakeVoid(_height_map.size_x * y + x); + + FreeHeightMap(); + GenerateWorldSetAbortCallback(NULL); +} |