Creating of maps from heightmaps. More...

#include "stdafx.h"
#include "heightmap.h"
#include "clear_map.h"
#include "void_map.h"
#include "error.h"
#include "saveload/saveload.h"
#include "bmp.h"
#include "gfx_func.h"
#include "fios.h"
#include "fileio_func.h"
#include "table/strings.h"
#include "safeguards.h"
#include <png.h>

Functions
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 load the image.

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, NTSC Colour Space)

static void	ReadHeightmapPNGImageData (std::span< uint8_t > map, png_structp png_ptr, png_infop info_ptr)
	The PNG Heightmap loader.

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	ReadHeightmapBMPImageData (std::span< uint8_t > map, const BmpInfo &info, const BmpData &data)
	The BMP Heightmap loader.

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.

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 data.

void	FixSlopes ()
	This function takes care of the fact that land in OpenTTD can never differ more than 1 in height.

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.

bool	GetHeightmapDimensions (DetailedFileType dft, const char filename, uint x, uint *y)
	Get the dimensions of a heightmap.

bool	LoadHeightmap (DetailedFileType dft, const char *filename)
	Load a heightmap from file and change the map in its current dimensions to a landscape representing the heightmap.

void	FlatEmptyWorld (uint8_t tile_height)
	Make an empty world where all tiles are of height 'tile_height'.

Variables
static const uint	MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS = 2 * MAX_MAP_SIZE
	Maximum number of pixels for one dimension of a heightmap image.

static const uint	MAX_HEIGHTMAP_SIZE_PIXELS = 256 << 20

Detailed Description

Creating of maps from heightmaps.

Definition in file heightmap.cpp.

Function Documentation

◆ FixSlopes()

void FixSlopes ( )

This function takes care of the fact that land in OpenTTD can never differ more than 1 in height.

Definition at line 399 of file heightmap.cpp.

References MAX_TILE_HEIGHT, SetTileHeight(), Map::SizeX(), Map::SizeY(), TileHeight(), and TileXY().

Referenced by FlatEmptyWorld(), GenerateLandscape(), and LoadHeightmap().

◆ FlatEmptyWorld()

void FlatEmptyWorld ( uint8_t tile_height )

Make an empty world where all tiles are of height 'tile_height'.

Parameters

tile_height of the desired new empty world

Definition at line 521 of file heightmap.cpp.

References _settings_game, GameSettings::construction, FixSlopes(), ConstructionSettings::freeform_edges, MarkWholeScreenDirty(), SetTileHeight(), Map::SizeX(), Map::SizeY(), and TileXY().

Referenced by _GenerateWorld().

◆ GetHeightmapDimensions()

bool GetHeightmapDimensions	(	DetailedFileType	dft,
		const char *	filename,
		uint *	x,
		uint *	y
	)

Get the dimensions of a heightmap.

Parameters

dft	Type of image file.
filename	to query
x	dimension x
y	dimension y

Returns: Returns false if loading of the image failed.

Definition at line 488 of file heightmap.cpp.

References ReadHeightMap().

◆ GrayscaleToMapHeights()

static void GrayscaleToMapHeights	(	uint	img_width,
		uint	img_height,
		std::span< const uint8_t >	map
	)

static

Converts a given grayscale map to something that fits in OTTD map system and create a map of that data.

Parameters

img_width	the with of the image in pixels/tiles
img_height	the height of the image in pixels/tiles
map	the input map

Definition at line 303 of file heightmap.cpp.

References _settings_game, CLEAR_GRASS, GameSettings::construction, DistanceFromEdge(), ConstructionSettings::freeform_edges, GameSettings::game_creation, GameCreationSettings::heightmap_height, GameCreationSettings::heightmap_rotation, HM_CLOCKWISE, HM_COUNTER_CLOCKWISE, IsInnerTile(), MakeClear(), MakeVoid(), MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS, SetTileHeight(), Map::SizeX(), Map::SizeY(), and TileXY().

Referenced by LoadHeightmap().

◆ IsValidHeightmapDimension()

static bool IsValidHeightmapDimension	(	size_t	width,
		size_t	height
	)

inlinestatic

Check whether the loaded dimension of the heightmap image are considered valid enough to attempt to load the image.

In other words, the width and height are not beyond the MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS limit and the total number of pixels does not exceed MAX_HEIGHTMAP_SIZE_PIXELS. A width or height less than 1 are disallowed too.

Parameters

width	The width of the to be loaded height map.
height	The height of the to be loaded height map.

Returns: True iff the dimensions are within the limits.

Definition at line 52 of file heightmap.cpp.

References MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS.

Referenced by ReadHeightmapBMP(), and ReadHeightmapPNG().

◆ LoadHeightmap()

bool LoadHeightmap	(	DetailedFileType	dft,
		const char *	filename
	)

Load a heightmap from file and change the map in its current dimensions to a landscape representing the heightmap.

It converts pixels to height. The brighter, the higher.

Parameters

dft	Type of image file.
filename	of the heightmap file to be imported

Definition at line 500 of file heightmap.cpp.

References FixSlopes(), GrayscaleToMapHeights(), MarkWholeScreenDirty(), and ReadHeightMap().

Referenced by GenerateLandscape().

◆ ReadHeightMap()

static bool ReadHeightMap	(	DetailedFileType	dft,
		const char *	filename,
		uint *	x,
		uint *	y,
		std::vector< uint8_t > *	map
	)

static

Reads the heightmap with the correct file reader.

Parameters

	dft	Type of image file.
	filename	Name of the file to load.
[out]	x	Length of the image.
[out]	y	Height of the image.
[in,out]	map	If not `nullptr`, destination to store the loaded block of image data.

Returns: Whether loading was successful.

Definition at line 464 of file heightmap.cpp.

References DFT_HEIGHTMAP_BMP, DFT_HEIGHTMAP_PNG, ReadHeightmapBMP(), and ReadHeightmapPNG().

Referenced by GetHeightmapDimensions(), and LoadHeightmap().

◆ ReadHeightmapBMP()

static bool ReadHeightmapBMP	(	const char *	filename,
		uint *	x,
		uint *	y,
		std::vector< uint8_t > *	map
	)

static

Reads the heightmap and/or size of the heightmap from a BMP file.

If map == nullptr only the size of the BMP is read, otherwise a map with grayscale pixels is allocated and assigned to *map.

Definition at line 258 of file heightmap.cpp.

References FioFOpenFile(), HEIGHTMAP_DIR, IsValidHeightmapDimension(), ReadHeightmapBMPImageData(), ShowErrorMessage(), and WL_ERROR.

Referenced by ReadHeightMap().

◆ ReadHeightmapBMPImageData()

static void ReadHeightmapBMPImageData	(	std::span< uint8_t >	map,
		const BmpInfo &	info,
		const BmpData &	data
	)

static

The BMP Heightmap loader.

For a non-gray palette of size 16 we assume that the order of the palette determines the height; the first entry is the sea (level 0), the second one level 1, etc.

For a palette of size 2 we assume that the order of the palette determines the height; the first entry is the sea (level 0), the second one is the land (level 1)

Definition at line 203 of file heightmap.cpp.

References BmpInfo::bpp, BmpInfo::height, BmpInfo::palette_size, RGBToGrayscale(), and BmpInfo::width.

Referenced by ReadHeightmapBMP().

◆ ReadHeightmapPNG()

static bool ReadHeightmapPNG	(	const char *	filename,
		uint *	x,
		uint *	y,
		std::vector< uint8_t > *	map
	)

static

Reads the heightmap and/or size of the heightmap from a PNG file.

If map == nullptr only the size of the PNG is read, otherwise a map with grayscale pixels is allocated and assigned to *map.

Definition at line 137 of file heightmap.cpp.

References FioFOpenFile(), HEIGHTMAP_DIR, IsValidHeightmapDimension(), ReadHeightmapPNGImageData(), ShowErrorMessage(), and WL_ERROR.

Referenced by ReadHeightMap().

◆ ReadHeightmapPNGImageData()

static void ReadHeightmapPNGImageData	(	std::span< uint8_t >	map,
		png_structp	png_ptr,
		png_infop	info_ptr
	)

static

The PNG Heightmap loader.

For a non-gray palette of size 16 we assume that the order of the palette determines the height; the first entry is the sea (level 0), the second one level 1, etc.

Definition at line 78 of file heightmap.cpp.

References RGBToGrayscale().

Referenced by ReadHeightmapPNG().

◆ RGBToGrayscale()

static uint8_t RGBToGrayscale	(	uint8_t	red,
		uint8_t	green,
		uint8_t	blue
	)

inlinestatic

Convert RGB colours to Grayscale using 29.9% Red, 58.7% Green, 11.4% Blue (average luminosity formula, NTSC Colour Space)

Definition at line 63 of file heightmap.cpp.

Referenced by ReadHeightmapBMPImageData(), and ReadHeightmapPNGImageData().

Variable Documentation

◆ MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS

const uint MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS = 2 * MAX_MAP_SIZE

static

Maximum number of pixels for one dimension of a heightmap image.

Do not allow images for which the longest side is twice the maximum number of tiles along the longest side of the (tile) map.

Definition at line 30 of file heightmap.cpp.

Referenced by GrayscaleToMapHeights(), and IsValidHeightmapDimension().

◆ MAX_HEIGHTMAP_SIZE_PIXELS

const uint MAX_HEIGHTMAP_SIZE_PIXELS = 256 << 20

static

Definition at line 35 of file heightmap.cpp.

Functions

Variables

Detailed Description

Function Documentation

◆ FixSlopes()

◆ FlatEmptyWorld()

◆ GetHeightmapDimensions()

◆ GrayscaleToMapHeights()

◆ IsValidHeightmapDimension()

◆ LoadHeightmap()

◆ ReadHeightMap()

◆ ReadHeightmapBMP()

◆ ReadHeightmapBMPImageData()

◆ ReadHeightmapPNG()

◆ ReadHeightmapPNGImageData()

◆ RGBToGrayscale()

Variable Documentation

◆ MAX_HEIGHTMAP_SIDE_LENGTH_IN_PIXELS

◆ MAX_HEIGHTMAP_SIZE_PIXELS