OpenTTD Source 20250205-master-gfd85ab1e2c
heightmap.cpp
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1/*
2 * This file is part of OpenTTD.
3 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
4 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
5 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
6 */
7
10#include "stdafx.h"
11#include "heightmap.h"
12#include "clear_map.h"
13#include "void_map.h"
14#include "error.h"
15#include "saveload/saveload.h"
16#include "bmp.h"
17#include "gfx_func.h"
18#include "fios.h"
19#include "fileio_func.h"
20
21#include "table/strings.h"
22
23#include "safeguards.h"
24
31
32/*
33 * Maximum size in pixels of the heightmap image.
34 */
35static const uint MAX_HEIGHTMAP_SIZE_PIXELS = 256 << 20; // ~256 million
36/*
37 * When loading a PNG or BMP the 24 bpp variant requires at least 4 bytes per pixel
38 * of memory to load the data. Make sure the "reasonable" limit is well within the
39 * maximum amount of memory allocatable on 32 bit platforms.
40 */
41static_assert(MAX_HEIGHTMAP_SIZE_PIXELS < UINT32_MAX / 8);
42
52static inline bool IsValidHeightmapDimension(size_t width, size_t height)
53{
54 return (uint64_t)width * height <= MAX_HEIGHTMAP_SIZE_PIXELS &&
55 width > 0 && width <= MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS &&
56 height > 0 && height <= MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS;
57}
58
63static inline uint8_t RGBToGrayscale(uint8_t red, uint8_t green, uint8_t blue)
64{
65 /* To avoid doubles and stuff, multiply it with a total of 65536 (16bits), then
66 * divide by it to normalize the value to a byte again. */
67 return ((red * 19595) + (green * 38470) + (blue * 7471)) / 65536;
68}
69
70
71#ifdef WITH_PNG
72
73#include <png.h>
74
78static void ReadHeightmapPNGImageData(std::span<uint8_t> map, png_structp png_ptr, png_infop info_ptr)
79{
80 uint x, y;
81 uint8_t gray_palette[256];
82 png_bytep *row_pointers = nullptr;
83 bool has_palette = png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_PALETTE;
84 uint channels = png_get_channels(png_ptr, info_ptr);
85
86 /* Get palette and convert it to grayscale */
87 if (has_palette) {
88 int i;
89 int palette_size;
90 png_color *palette;
91 bool all_gray = true;
92
93 png_get_PLTE(png_ptr, info_ptr, &palette, &palette_size);
94 for (i = 0; i < palette_size && (palette_size != 16 || all_gray); i++) {
95 all_gray &= palette[i].red == palette[i].green && palette[i].red == palette[i].blue;
96 gray_palette[i] = RGBToGrayscale(palette[i].red, palette[i].green, palette[i].blue);
97 }
98
105 if (palette_size == 16 && !all_gray) {
106 for (i = 0; i < palette_size; i++) {
107 gray_palette[i] = 256 * i / palette_size;
108 }
109 }
110 }
111
112 row_pointers = png_get_rows(png_ptr, info_ptr);
113
114 /* Read the raw image data and convert in 8-bit grayscale */
115 for (x = 0; x < png_get_image_width(png_ptr, info_ptr); x++) {
116 for (y = 0; y < png_get_image_height(png_ptr, info_ptr); y++) {
117 uint8_t *pixel = &map[y * png_get_image_width(png_ptr, info_ptr) + x];
118 uint x_offset = x * channels;
119
120 if (has_palette) {
121 *pixel = gray_palette[row_pointers[y][x_offset]];
122 } else if (channels == 3) {
123 *pixel = RGBToGrayscale(row_pointers[y][x_offset + 0],
124 row_pointers[y][x_offset + 1], row_pointers[y][x_offset + 2]);
125 } else {
126 *pixel = row_pointers[y][x_offset];
127 }
128 }
129 }
130}
131
137static bool ReadHeightmapPNG(const char *filename, uint *x, uint *y, std::vector<uint8_t> *map)
138{
139 png_structp png_ptr = nullptr;
140 png_infop info_ptr = nullptr;
141
142 auto fp = FioFOpenFile(filename, "rb", HEIGHTMAP_DIR);
143 if (!fp.has_value()) {
144 ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_FILE_NOT_FOUND, WL_ERROR);
145 return false;
146 }
147
148 png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
149 if (png_ptr == nullptr) {
150 ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_MISC, WL_ERROR);
151 return false;
152 }
153
154 info_ptr = png_create_info_struct(png_ptr);
155 if (info_ptr == nullptr || setjmp(png_jmpbuf(png_ptr))) {
156 ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_MISC, WL_ERROR);
157 png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
158 return false;
159 }
160
161 png_init_io(png_ptr, *fp);
162
163 /* Allocate memory and read image, without alpha or 16-bit samples
164 * (result is either 8-bit indexed/grayscale or 24-bit RGB) */
165 png_set_packing(png_ptr);
166 png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_PACKING | PNG_TRANSFORM_STRIP_ALPHA | PNG_TRANSFORM_STRIP_16, nullptr);
167
168 /* Maps of wrong colour-depth are not used.
169 * (this should have been taken care of by stripping alpha and 16-bit samples on load) */
170 if ((png_get_channels(png_ptr, info_ptr) != 1) && (png_get_channels(png_ptr, info_ptr) != 3) && (png_get_bit_depth(png_ptr, info_ptr) != 8)) {
171 ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_IMAGE_TYPE, WL_ERROR);
172 png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
173 return false;
174 }
175
176 uint width = png_get_image_width(png_ptr, info_ptr);
177 uint height = png_get_image_height(png_ptr, info_ptr);
178
179 if (!IsValidHeightmapDimension(width, height)) {
180 ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_HEIGHTMAP_TOO_LARGE, WL_ERROR);
181 png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
182 return false;
183 }
184
185 if (map != nullptr) {
186 map->resize(static_cast<size_t>(width) * height);
187 ReadHeightmapPNGImageData(*map, png_ptr, info_ptr);
188 }
189
190 *x = width;
191 *y = height;
192
193 png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
194 return true;
195}
196
197#endif /* WITH_PNG */
198
199
203static void ReadHeightmapBMPImageData(std::span<uint8_t> map, const BmpInfo &info, const BmpData &data)
204{
205 uint8_t gray_palette[256];
206
207 if (!data.palette.empty()) {
208 bool all_gray = true;
209
210 if (info.palette_size != 2) {
211 for (uint i = 0; i < info.palette_size && (info.palette_size != 16 || all_gray); i++) {
212 all_gray &= data.palette[i].r == data.palette[i].g && data.palette[i].r == data.palette[i].b;
213 gray_palette[i] = RGBToGrayscale(data.palette[i].r, data.palette[i].g, data.palette[i].b);
214 }
215
222 if (info.palette_size == 16 && !all_gray) {
223 for (uint i = 0; i < info.palette_size; i++) {
224 gray_palette[i] = 256 * i / info.palette_size;
225 }
226 }
227 } else {
232 gray_palette[0] = 0;
233 gray_palette[1] = 16;
234 }
235 }
236
237 /* Read the raw image data and convert in 8-bit grayscale */
238 for (uint y = 0; y < info.height; y++) {
239 uint8_t *pixel = &map[y * static_cast<size_t>(info.width)];
240 const uint8_t *bitmap = &data.bitmap[y * static_cast<size_t>(info.width) * (info.bpp == 24 ? 3 : 1)];
241
242 for (uint x = 0; x < info.width; x++) {
243 if (info.bpp != 24) {
244 *pixel++ = gray_palette[*bitmap++];
245 } else {
246 *pixel++ = RGBToGrayscale(*bitmap, *(bitmap + 1), *(bitmap + 2));
247 bitmap += 3;
248 }
249 }
250 }
251}
252
258static bool ReadHeightmapBMP(const char *filename, uint *x, uint *y, std::vector<uint8_t> *map)
259{
260 auto f = FioFOpenFile(filename, "rb", HEIGHTMAP_DIR);
261 if (!f.has_value()) {
262 ShowErrorMessage(STR_ERROR_BMPMAP, STR_ERROR_PNGMAP_FILE_NOT_FOUND, WL_ERROR);
263 return false;
264 }
265
266 RandomAccessFile file(filename, HEIGHTMAP_DIR);
267 BmpInfo info{};
268 BmpData data{};
269
270 if (!BmpReadHeader(file, info, data)) {
271 ShowErrorMessage(STR_ERROR_BMPMAP, STR_ERROR_BMPMAP_IMAGE_TYPE, WL_ERROR);
272 return false;
273 }
274
275 if (!IsValidHeightmapDimension(info.width, info.height)) {
276 ShowErrorMessage(STR_ERROR_BMPMAP, STR_ERROR_HEIGHTMAP_TOO_LARGE, WL_ERROR);
277 return false;
278 }
279
280 if (map != nullptr) {
281 if (!BmpReadBitmap(file, info, data)) {
282 ShowErrorMessage(STR_ERROR_BMPMAP, STR_ERROR_BMPMAP_IMAGE_TYPE, WL_ERROR);
283 return false;
284 }
285
286 map->resize(static_cast<size_t>(info.width) * info.height);
287 ReadHeightmapBMPImageData(*map, info, data);
288 }
289
290 *x = info.width;
291 *y = info.height;
292
293 return true;
294}
295
303static void GrayscaleToMapHeights(uint img_width, uint img_height, std::span<const uint8_t> map)
304{
305 /* Defines the detail of the aspect ratio (to avoid doubles) */
306 const uint num_div = 16384;
307 /* Ensure multiplication with num_div does not cause overflows. */
308 static_assert(num_div <= std::numeric_limits<uint>::max() / MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS);
309
310 uint width, height;
311 uint row, col;
312 uint row_pad = 0, col_pad = 0;
313 uint img_scale;
314 uint img_row, img_col;
315 TileIndex tile;
316
317 /* Get map size and calculate scale and padding values */
319 default: NOT_REACHED();
321 width = Map::SizeX();
322 height = Map::SizeY();
323 break;
324 case HM_CLOCKWISE:
325 width = Map::SizeY();
326 height = Map::SizeX();
327 break;
328 }
329
330 if ((img_width * num_div) / img_height > ((width * num_div) / height)) {
331 /* Image is wider than map - center vertically */
332 img_scale = (width * num_div) / img_width;
333 row_pad = (1 + height - ((img_height * img_scale) / num_div)) / 2;
334 } else {
335 /* Image is taller than map - center horizontally */
336 img_scale = (height * num_div) / img_height;
337 col_pad = (1 + width - ((img_width * img_scale) / num_div)) / 2;
338 }
339
341 for (uint x = 0; x < Map::SizeX(); x++) MakeVoid(TileXY(x, 0));
342 for (uint y = 0; y < Map::SizeY(); y++) MakeVoid(TileXY(0, y));
343 }
344
345 /* Form the landscape */
346 for (row = 0; row < height; row++) {
347 for (col = 0; col < width; col++) {
349 default: NOT_REACHED();
350 case HM_COUNTER_CLOCKWISE: tile = TileXY(col, row); break;
351 case HM_CLOCKWISE: tile = TileXY(row, col); break;
352 }
353
354 /* Check if current tile is within the 1-pixel map edge or padding regions */
356 (row < row_pad) || (row >= (height - row_pad - (_settings_game.construction.freeform_edges ? 0 : 1))) ||
357 (col < col_pad) || (col >= (width - col_pad - (_settings_game.construction.freeform_edges ? 0 : 1)))) {
358 SetTileHeight(tile, 0);
359 } else {
360 /* Use nearest neighbour resizing to scale map data.
361 * We rotate the map 45 degrees (counter)clockwise */
362 img_row = (((row - row_pad) * num_div) / img_scale);
364 default: NOT_REACHED();
366 img_col = (((width - 1 - col - col_pad) * num_div) / img_scale);
367 break;
368 case HM_CLOCKWISE:
369 img_col = (((col - col_pad) * num_div) / img_scale);
370 break;
371 }
372
373 assert(img_row < img_height);
374 assert(img_col < img_width);
375
376 uint heightmap_height = map[img_row * img_width + img_col];
377
378 if (heightmap_height > 0) {
379 /* 0 is sea level.
380 * Other grey scales are scaled evenly to the available height levels > 0.
381 * (The coastline is independent from the number of height levels) */
382 heightmap_height = 1 + (heightmap_height - 1) * _settings_game.game_creation.heightmap_height / 255;
383 }
384
385 SetTileHeight(tile, heightmap_height);
386 }
387 /* Only clear the tiles within the map area. */
388 if (IsInnerTile(tile)) {
389 MakeClear(tile, CLEAR_GRASS, 3);
390 }
391 }
392 }
393}
394
400{
401 uint width, height;
402 int row, col;
403 uint8_t current_tile;
404
405 /* Adjust height difference to maximum one horizontal/vertical change. */
406 width = Map::SizeX();
407 height = Map::SizeY();
408
409 /* Top and left edge */
410 for (row = 0; (uint)row < height; row++) {
411 for (col = 0; (uint)col < width; col++) {
412 current_tile = MAX_TILE_HEIGHT;
413 if (col != 0) {
414 /* Find lowest tile; either the top or left one */
415 current_tile = TileHeight(TileXY(col - 1, row)); // top edge
416 }
417 if (row != 0) {
418 if (TileHeight(TileXY(col, row - 1)) < current_tile) {
419 current_tile = TileHeight(TileXY(col, row - 1)); // left edge
420 }
421 }
422
423 /* Does the height differ more than one? */
424 if (TileHeight(TileXY(col, row)) >= (uint)current_tile + 2) {
425 /* Then change the height to be no more than one */
426 SetTileHeight(TileXY(col, row), current_tile + 1);
427 }
428 }
429 }
430
431 /* Bottom and right edge */
432 for (row = height - 1; row >= 0; row--) {
433 for (col = width - 1; col >= 0; col--) {
434 current_tile = MAX_TILE_HEIGHT;
435 if ((uint)col != width - 1) {
436 /* Find lowest tile; either the bottom and right one */
437 current_tile = TileHeight(TileXY(col + 1, row)); // bottom edge
438 }
439
440 if ((uint)row != height - 1) {
441 if (TileHeight(TileXY(col, row + 1)) < current_tile) {
442 current_tile = TileHeight(TileXY(col, row + 1)); // right edge
443 }
444 }
445
446 /* Does the height differ more than one? */
447 if (TileHeight(TileXY(col, row)) >= (uint)current_tile + 2) {
448 /* Then change the height to be no more than one */
449 SetTileHeight(TileXY(col, row), current_tile + 1);
450 }
451 }
452 }
453}
454
464static bool ReadHeightMap(DetailedFileType dft, const char *filename, uint *x, uint *y, std::vector<uint8_t> *map)
465{
466 switch (dft) {
467 default:
468 NOT_REACHED();
469
470#ifdef WITH_PNG
472 return ReadHeightmapPNG(filename, x, y, map);
473#endif /* WITH_PNG */
474
476 return ReadHeightmapBMP(filename, x, y, map);
477 }
478}
479
488bool GetHeightmapDimensions(DetailedFileType dft, const char *filename, uint *x, uint *y)
489{
490 return ReadHeightMap(dft, filename, x, y, nullptr);
491}
492
500bool LoadHeightmap(DetailedFileType dft, const char *filename)
501{
502 uint x, y;
503 std::vector<uint8_t> map;
504
505 if (!ReadHeightMap(dft, filename, &x, &y, &map)) {
506 return false;
507 }
508
509 GrayscaleToMapHeights(x, y, map);
510
511 FixSlopes();
513
514 return true;
515}
516
521void FlatEmptyWorld(uint8_t tile_height)
522{
523 int edge_distance = _settings_game.construction.freeform_edges ? 0 : 2;
524 for (uint row = edge_distance; row < Map::SizeY() - edge_distance; row++) {
525 for (uint col = edge_distance; col < Map::SizeX() - edge_distance; col++) {
526 SetTileHeight(TileXY(col, row), tile_height);
527 }
528 }
529
530 FixSlopes();
532}
Read and write support for bmps.
A file from which bytes, words and double words are read in (potentially) a random order.
Map accessors for 'clear' tiles.
@ CLEAR_GRASS
0-3
Definition clear_map.h:20
void MakeClear(Tile t, ClearGround g, uint density)
Make a clear tile.
Definition clear_map.h:259
Functions related to errors.
@ WL_ERROR
Errors (eg. saving/loading failed)
Definition error.h:26
void ShowErrorMessage(StringID summary_msg, int x, int y, CommandCost cc)
Display an error message in a window.
std::optional< FileHandle > FioFOpenFile(const std::string &filename, const char *mode, Subdirectory subdir, size_t *filesize)
Opens a OpenTTD file somewhere in a personal or global directory.
Definition fileio.cpp:243
Functions for Standard In/Out file operations.
DetailedFileType
Kinds of files in each AbstractFileType.
Definition fileio_type.h:29
@ DFT_HEIGHTMAP_BMP
BMP file.
Definition fileio_type.h:35
@ DFT_HEIGHTMAP_PNG
PNG file.
Definition fileio_type.h:36
@ HEIGHTMAP_DIR
Subdirectory of scenario for heightmaps.
Declarations for savegames operations.
Functions related to the gfx engine.
void MarkWholeScreenDirty()
This function mark the whole screen as dirty.
Definition gfx.cpp:1529
static const uint MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS
Maximum number of pixels for one dimension of a heightmap image.
Definition heightmap.cpp:30
static void GrayscaleToMapHeights(uint img_width, uint img_height, std::span< const uint8_t > map)
Converts a given grayscale map to something that fits in OTTD map system and create a map of that dat...
bool LoadHeightmap(DetailedFileType dft, const char *filename)
Load a heightmap from file and change the map in its current dimensions to a landscape representing t...
static uint8_t RGBToGrayscale(uint8_t red, uint8_t green, uint8_t blue)
Convert RGB colours to Grayscale using 29.9% Red, 58.7% Green, 11.4% Blue (average luminosity formula...
Definition heightmap.cpp:63
bool GetHeightmapDimensions(DetailedFileType dft, const char *filename, uint *x, uint *y)
Get the dimensions of a heightmap.
void FlatEmptyWorld(uint8_t tile_height)
Make an empty world where all tiles are of height 'tile_height'.
static bool ReadHeightmapPNG(const char *filename, uint *x, uint *y, std::vector< uint8_t > *map)
Reads the heightmap and/or size of the heightmap from a PNG file.
static void ReadHeightmapPNGImageData(std::span< uint8_t > map, png_structp png_ptr, png_infop info_ptr)
The PNG Heightmap loader.
Definition heightmap.cpp:78
static bool IsValidHeightmapDimension(size_t width, size_t height)
Check whether the loaded dimension of the heightmap image are considered valid enough to attempt to l...
Definition heightmap.cpp:52
void FixSlopes()
This function takes care of the fact that land in OpenTTD can never differ more than 1 in height.
static void ReadHeightmapBMPImageData(std::span< uint8_t > map, const BmpInfo &info, const BmpData &data)
The BMP Heightmap loader.
static bool ReadHeightMap(DetailedFileType dft, const char *filename, uint *x, uint *y, std::vector< uint8_t > *map)
Reads the heightmap with the correct file reader.
static bool ReadHeightmapBMP(const char *filename, uint *x, uint *y, std::vector< uint8_t > *map)
Reads the heightmap and/or size of the heightmap from a BMP file.
Functions related to creating heightmaps from files.
@ HM_CLOCKWISE
Rotate the map clockwise 45 degrees.
Definition heightmap.h:21
@ HM_COUNTER_CLOCKWISE
Rotate the map counter clockwise 45 degrees.
Definition heightmap.h:20
uint DistanceFromEdge(TileIndex tile)
Param the minimum distance to an edge.
Definition map.cpp:203
static debug_inline TileIndex TileXY(uint x, uint y)
Returns the TileIndex of a coordinate.
Definition map_func.h:373
static const uint MAX_MAP_SIZE
Maximal map size = 4096.
Definition map_type.h:40
A number of safeguards to prevent using unsafe methods.
Functions/types related to saving and loading games.
GameSettings _settings_game
Game settings of a running game or the scenario editor.
Definition settings.cpp:57
Definition of base types and functions in a cross-platform compatible way.
Definition bmp.h:26
Definition bmp.h:16
uint32_t height
bitmap height
Definition bmp.h:19
uint32_t width
bitmap width
Definition bmp.h:18
uint32_t palette_size
number of colours in palette
Definition bmp.h:23
uint16_t bpp
bits per pixel
Definition bmp.h:21
bool freeform_edges
allow terraforming the tiles at the map edges
uint8_t heightmap_rotation
rotation director for the heightmap
uint8_t heightmap_height
highest mountain for heightmap (towards what it scales)
ConstructionSettings construction
construction of things in-game
GameCreationSettings game_creation
settings used during the creation of a game (map)
static uint SizeY()
Get the size of the map along the Y.
Definition map_func.h:279
static debug_inline uint SizeX()
Get the size of the map along the X.
Definition map_func.h:270
bool IsInnerTile(Tile tile)
Check if a tile is within the map (not a border)
Definition tile_map.h:109
void SetTileHeight(Tile tile, uint height)
Sets the height of a tile.
Definition tile_map.h:57
static debug_inline uint TileHeight(Tile tile)
Returns the height of a tile.
Definition tile_map.h:29
static const uint MAX_TILE_HEIGHT
Maximum allowed tile height.
Definition tile_type.h:24
Map accessors for void tiles.
void MakeVoid(Tile t)
Make a nice void tile ;)
Definition void_map.h:19