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86 lines
2.8 KiB
86 lines
2.8 KiB
/** |
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* @file path.h |
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* |
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* Interface of the path finding algorithms. |
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*/ |
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#pragma once |
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#include <cstdint> |
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#include <optional> |
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#include <function_ref.hpp> |
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#include "engine/point.hpp" |
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#include "utils/attributes.h" |
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namespace devilution { |
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constexpr size_t MaxPathLength = 25; |
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bool IsTileNotSolid(Point position); |
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bool IsTileSolid(Point position); |
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/** |
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* @brief Checks the position is solid or blocked by an object |
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*/ |
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bool IsTileWalkable(Point position, bool ignoreDoors = false); |
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/** |
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* @brief Checks if the position contains an object, player, monster, or solid dungeon piece |
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*/ |
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bool IsTileOccupied(Point position); |
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/** |
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* @brief Find the shortest path from startPosition to destinationPosition, using PosOk(Point) to check that each step is a valid position. |
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* Store the step directions (corresponds to an index in PathDirs) in path, which must have room for 24 steps |
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*/ |
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int FindPath(tl::function_ref<bool(Point)> posOk, Point startPosition, Point destinationPosition, int8_t path[MaxPathLength]); |
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/** |
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* @brief check if stepping from a given position to a neighbouring tile cuts a corner. |
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* |
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* If you step from A to B, both Xs need to be clear: |
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* |
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* AX |
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* XB |
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* |
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* @return true if step is allowed |
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*/ |
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bool CanStep(Point startPosition, Point destinationPosition); |
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/** For iterating over the 8 possible movement directions */ |
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const Displacement PathDirs[8] = { |
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// clang-format off |
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{ -1, -1 }, //Direction::North |
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{ -1, 1 }, //Direction::West |
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{ 1, -1 }, //Direction::East |
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{ 1, 1 }, //Direction::South |
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{ -1, 0 }, //Direction::NorthWest |
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{ 0, -1 }, //Direction::NorthEast |
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{ 1, 0 }, //Direction::SouthEast |
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{ 0, 1 }, //Direction::SouthWest |
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// clang-format on |
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}; |
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/** |
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* @brief Searches for the closest position that passes the check in expanding "rings". |
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* |
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* The search space is roughly equivalent to a square of tiles where the walking distance is equal to the radius except |
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* the corners are "rounded" (inset) by one tile. For example the following is a search space of radius 4: |
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* _XXXXXXX_ |
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* XX_____XX |
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* X_______X |
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* < snip > |
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* X_______X |
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* XX_____XX |
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* _XXXXXXX_ |
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* |
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* @param posOk Used to check if a position is valid |
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* @param startingPosition dungeon tile location to start the search from |
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* @param minimumRadius A value from 0 to 50, allows skipping nearby tiles (e.g. specify radius 1 to skip checking the starting tile) |
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* @param maximumRadius The maximum distance to check, defaults to 18 for vanilla compatibility but supports values up to 50 |
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* @return either the closest valid point or an empty optional |
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*/ |
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std::optional<Point> FindClosestValidPosition(tl::function_ref<bool(Point)> posOk, Point startingPosition, unsigned int minimumRadius = 0, unsigned int maximumRadius = 18); |
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} // namespace devilution
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