(svn r7710) [cbh] - Fix: [YAPF] one more assert fixed. Call from the TrainController() added by (r7705) has broken YAPF because it was called when vehicle was already on the next tile (with cbh choice). Before it was always called before the train entered tile with choice.
/* $Id$ */
#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);
}