pandemonium_engine/modules/wfc/tiling_wfc.h

346 lines
10 KiB
C++

#ifndef FAST_WFC_TILING_WFC_HPP_
#define FAST_WFC_TILING_WFC_HPP_
#include <unordered_map>
#include <vector>
#include "array_2d.h"
#include "wfc.h"
// The distinct symmetries of a tile.
// It represents how the tile behave when it is rotated or reflected
enum class Symmetry {
X,
T,
I,
L,
backslash,
P
};
/**
// Return the number of possible distinct orientations for a tile.
// An orientation is a combination of rotations and reflections.
*/
constexpr unsigned nb_of_possible_orientations(const Symmetry &symmetry) {
switch (symmetry) {
case Symmetry::X:
return 1;
case Symmetry::I:
case Symmetry::backslash:
return 2;
case Symmetry::T:
case Symmetry::L:
return 4;
default:
return 8;
}
}
// A tile that can be placed on the board.
template <typename T>
struct Tile {
std::vector<Array2D<T>> data; // The different orientations of the tile
Symmetry symmetry; // The symmetry of the tile
double weight; // Its weight on the distribution of presence of tiles
// Generate the map associating an orientation id to the orientation
// id obtained when rotating 90° anticlockwise the tile.
static std::vector<unsigned> generate_rotation_map(const Symmetry &symmetry) {
switch (symmetry) {
case Symmetry::X:
return { 0 };
case Symmetry::I:
case Symmetry::backslash:
return { 1, 0 };
case Symmetry::T:
case Symmetry::L:
return { 1, 2, 3, 0 };
case Symmetry::P:
default:
return { 1, 2, 3, 0, 5, 6, 7, 4 };
}
}
// Generate the map associating an orientation id to the orientation
// id obtained when reflecting the tile along the x axis.
static std::vector<unsigned> generate_reflection_map(const Symmetry &symmetry) {
switch (symmetry) {
case Symmetry::X:
return { 0 };
case Symmetry::I:
return { 0, 1 };
case Symmetry::backslash:
return { 1, 0 };
case Symmetry::T:
return { 0, 3, 2, 1 };
case Symmetry::L:
return { 1, 0, 3, 2 };
case Symmetry::P:
default:
return { 4, 7, 6, 5, 0, 3, 2, 1 };
}
}
// Generate the map associating an orientation id and an action to the
// resulting orientation id.
// Actions 0, 1, 2, and 3 are 0°, 90°, 180°, and 270° anticlockwise rotations.
// Actions 4, 5, 6, and 7 are actions 0, 1, 2, and 3 preceded by a reflection
// on the x axis.
static std::vector<std::vector<unsigned>> generate_action_map(const Symmetry &symmetry) {
std::vector<unsigned> rotation_map = generate_rotation_map(symmetry);
std::vector<unsigned> reflection_map = generate_reflection_map(symmetry);
size_t size = rotation_map.size();
std::vector<std::vector<unsigned>> action_map(8,
std::vector<unsigned>(size));
for (size_t i = 0; i < size; ++i) {
action_map[0][i] = i;
}
for (size_t a = 1; a < 4; ++a) {
for (size_t i = 0; i < size; ++i) {
action_map[a][i] = rotation_map[action_map[a - 1][i]];
}
}
for (size_t i = 0; i < size; ++i) {
action_map[4][i] = reflection_map[action_map[0][i]];
}
for (size_t a = 5; a < 8; ++a) {
for (size_t i = 0; i < size; ++i) {
action_map[a][i] = rotation_map[action_map[a - 1][i]];
}
}
return action_map;
}
// Generate all distincts rotations of a 2D array given its symmetries;
static std::vector<Array2D<T>> generate_oriented(Array2D<T> data,
Symmetry symmetry) {
std::vector<Array2D<T>> oriented;
oriented.push_back(data);
switch (symmetry) {
case Symmetry::I:
case Symmetry::backslash:
oriented.push_back(data.rotated());
break;
case Symmetry::T:
case Symmetry::L:
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated());
break;
case Symmetry::P:
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated().reflected());
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated());
oriented.push_back(data = data.rotated());
break;
default:
break;
}
return oriented;
}
// Create a tile with its differents orientations, its symmetries and its
// weight on the distribution of tiles.
Tile(std::vector<Array2D<T>> data, Symmetry symmetry, double weight) :
data(data), symmetry(symmetry), weight(weight) {}
// Create a tile with its base orientation, its symmetries and its
// weight on the distribution of tiles.
// The other orientations are generated with its first one.
Tile(Array2D<T> data, Symmetry symmetry, double weight) :
data(generate_oriented(data, symmetry)), symmetry(symmetry), weight(weight) {}
};
struct TilingWFCOptions {
bool periodic_output;
};
// Class generating a new image with the tiling WFC algorithm.
template <typename T>
class TilingWFC {
private:
std::vector<Tile<T>> tiles;
std::vector<std::pair<unsigned, unsigned>> id_to_oriented_tile;
std::vector<std::vector<unsigned>> oriented_tile_ids;
TilingWFCOptions options;
WFC wfc;
public:
unsigned height;
unsigned width;
private:
// Generate mapping from id to oriented tiles and vice versa.
static std::pair<std::vector<std::pair<unsigned, unsigned>>,
std::vector<std::vector<unsigned>>>
generate_oriented_tile_ids(const std::vector<Tile<T>> &tiles) {
std::vector<std::pair<unsigned, unsigned>> id_to_oriented_tile;
std::vector<std::vector<unsigned>> oriented_tile_ids;
unsigned id = 0;
for (unsigned i = 0; i < tiles.size(); i++) {
oriented_tile_ids.push_back({});
for (unsigned j = 0; j < tiles[i].data.size(); j++) {
id_to_oriented_tile.push_back({ i, j });
oriented_tile_ids[i].push_back(id);
id++;
}
}
return { id_to_oriented_tile, oriented_tile_ids };
}
// Generate the propagator which will be used in the wfc algorithm.
static std::vector<std::array<std::vector<unsigned>, 4>> generate_propagator(
const std::vector<std::tuple<unsigned, unsigned, unsigned, unsigned>>
&neighbors,
std::vector<Tile<T>> tiles,
std::vector<std::pair<unsigned, unsigned>> id_to_oriented_tile,
std::vector<std::vector<unsigned>> oriented_tile_ids) {
size_t nb_oriented_tiles = id_to_oriented_tile.size();
std::vector<std::array<std::vector<bool>, 4>> dense_propagator(
nb_oriented_tiles, { std::vector<bool>(nb_oriented_tiles, false), std::vector<bool>(nb_oriented_tiles, false), std::vector<bool>(nb_oriented_tiles, false), std::vector<bool>(nb_oriented_tiles, false) });
for (auto neighbor : neighbors) {
unsigned tile1 = std::get<0>(neighbor);
unsigned orientation1 = std::get<1>(neighbor);
unsigned tile2 = std::get<2>(neighbor);
unsigned orientation2 = std::get<3>(neighbor);
std::vector<std::vector<unsigned>> action_map1 =
Tile<T>::generate_action_map(tiles[tile1].symmetry);
std::vector<std::vector<unsigned>> action_map2 =
Tile<T>::generate_action_map(tiles[tile2].symmetry);
auto add = [&](unsigned action, unsigned direction) {
unsigned temp_orientation1 = action_map1[action][orientation1];
unsigned temp_orientation2 = action_map2[action][orientation2];
unsigned oriented_tile_id1 =
oriented_tile_ids[tile1][temp_orientation1];
unsigned oriented_tile_id2 =
oriented_tile_ids[tile2][temp_orientation2];
dense_propagator[oriented_tile_id1][direction][oriented_tile_id2] =
true;
direction = get_opposite_direction(direction);
dense_propagator[oriented_tile_id2][direction][oriented_tile_id1] =
true;
};
add(0, 2);
add(1, 0);
add(2, 1);
add(3, 3);
add(4, 1);
add(5, 3);
add(6, 2);
add(7, 0);
}
std::vector<std::array<std::vector<unsigned>, 4>> propagator(
nb_oriented_tiles);
for (size_t i = 0; i < nb_oriented_tiles; ++i) {
for (size_t j = 0; j < nb_oriented_tiles; ++j) {
for (size_t d = 0; d < 4; ++d) {
if (dense_propagator[i][d][j]) {
propagator[i][d].push_back(j);
}
}
}
}
return propagator;
}
// Get probability of presence of tiles.
static std::vector<double>
get_tiles_weights(const std::vector<Tile<T>> &tiles) {
std::vector<double> frequencies;
for (size_t i = 0; i < tiles.size(); ++i) {
for (size_t j = 0; j < tiles[i].data.size(); ++j) {
frequencies.push_back(tiles[i].weight / tiles[i].data.size());
}
}
return frequencies;
}
// Translate the generic WFC result into the image result
Array2D<T> id_to_tiling(Array2D<unsigned> ids) {
unsigned size = tiles[0].data[0].height;
Array2D<T> tiling(size * ids.height, size * ids.width);
for (unsigned i = 0; i < ids.height; i++) {
for (unsigned j = 0; j < ids.width; j++) {
std::pair<unsigned, unsigned> oriented_tile =
id_to_oriented_tile[ids.get(i, j)];
for (unsigned y = 0; y < size; y++) {
for (unsigned x = 0; x < size; x++) {
tiling.get(i * size + y, j * size + x) =
tiles[oriented_tile.first].data[oriented_tile.second].get(y, x);
}
}
}
}
return tiling;
}
void set_tile(unsigned tile_id, unsigned i, unsigned j) {
for (unsigned p = 0; p < id_to_oriented_tile.size(); p++) {
if (tile_id != p) {
wfc.remove_wave_pattern(i, j, p);
}
}
}
public:
// Construct the TilingWFC class to generate a tiled image.
TilingWFC(
const std::vector<Tile<T>> &tiles,
const std::vector<std::tuple<unsigned, unsigned, unsigned, unsigned>>
&neighbors,
const unsigned height, const unsigned width,
const TilingWFCOptions &options, int seed) :
tiles(tiles),
id_to_oriented_tile(generate_oriented_tile_ids(tiles).first),
oriented_tile_ids(generate_oriented_tile_ids(tiles).second),
options(options),
wfc(options.periodic_output, seed, get_tiles_weights(tiles),
generate_propagator(neighbors, tiles, id_to_oriented_tile,
oriented_tile_ids),
height, width),
height(height),
width(width) {}
// Set the tile at a specific position.
// Returns false if the given tile and orientation does not exist,
// or if the coordinates are not in the wave
bool set_tile(unsigned tile_id, unsigned orientation, unsigned i, unsigned j) {
if (tile_id >= oriented_tile_ids.size() || orientation >= oriented_tile_ids[tile_id].size() || i >= height || j >= width) {
return false;
}
unsigned oriented_tile_id = oriented_tile_ids[tile_id][orientation];
set_tile(oriented_tile_id, i, j);
return true;
}
// Run the tiling wfc and return the result if the algorithm succeeded
Array2D<T> run() {
Array2D<unsigned> a = wfc.run();
if (a.width == 0 && a.height == 0) {
return Array2D<T>(0, 0);
}
return id_to_tiling(a);
}
};
#endif // FAST_WFC_TILING_WFC_HPP_