Safe Haskell | None |
---|---|

Language | Haskell2010 |

Basic operations on 2D vectors represented in an efficient, but not unique, way.

- data Vector = Vector {}
- isUnit :: Vector -> Bool
- isDiagonal :: Vector -> Bool
- neg :: Vector -> Vector
- chessDistVector :: Vector -> Int
- euclidDistSqVector :: Vector -> Vector -> Int
- moves :: [Vector]
- movesCardinal :: [Vector]
- movesDiagonal :: [Vector]
- compassText :: Vector -> Text
- vicinity :: X -> Y -> Point -> [Point]
- vicinityCardinal :: X -> Y -> Point -> [Point]
- shift :: Point -> Vector -> Point
- shiftBounded :: X -> Y -> Point -> Vector -> Point
- trajectoryToPath :: Point -> [Vector] -> [Point]
- trajectoryToPathBounded :: X -> Y -> Point -> [Vector] -> [Point]
- vectorToFrom :: Point -> Point -> Vector
- pathToTrajectory :: [Point] -> [Vector]
- type RadianAngle = Double
- rotate :: RadianAngle -> Vector -> Vector
- towards :: Point -> Point -> Vector

# Documentation

2D vectors in cartesian representation. Coordinates grow to the right and down, so that the (1, 1) vector points to the bottom-right corner of the screen.

isDiagonal :: Vector -> Bool Source

Checks whether a unit vector is a diagonal direction, as opposed to cardinal. If the vector is not unit, it checks that the vector is not horizontal nor vertical.

chessDistVector :: Vector -> Int Source

The lenght of a vector in the chessboard metric, where diagonal moves cost 1.

euclidDistSqVector :: Vector -> Vector -> Int Source

Squared euclidean distance between two vectors.

Vectors of all unit moves in the chessboard metric, clockwise, starting north-west.

movesCardinal :: [Vector] Source

Vectors of all cardinal direction unit moves, clockwise, starting north.

movesDiagonal :: [Vector] Source

Vectors of all diagonal direction unit moves, clockwise, starting north.

compassText :: Vector -> Text Source

All (8 at most) closest neighbours of a point within an area.

All (4 at most) cardinal direction neighbours of a point within an area.

shiftBounded :: X -> Y -> Point -> Vector -> Point Source

Translate a point by a vector, but only if the result fits in an area.

trajectoryToPath :: Point -> [Vector] -> [Point] Source

A list of points that a list of vectors leads to.

trajectoryToPathBounded :: X -> Y -> Point -> [Vector] -> [Point] Source

A list of points that a list of vectors leads to, bounded by level size.

vectorToFrom :: Point -> Point -> Vector Source

The vector between the second point and the first. We have

shift pos1 (pos2 `vectorToFrom` pos1) == pos2

The arguments are in the same order as in the underlying scalar subtraction.

pathToTrajectory :: [Point] -> [Vector] Source

A list of vectors between a list of points.

type RadianAngle = Double Source

rotate :: RadianAngle -> Vector -> Vector Source

Rotate a vector by the given angle (expressed in radians) counterclockwise and return a unit vector approximately in the resulting direction.

towards :: Point -> Point -> Vector Source

Given two distinct positions, determine the direction (a unit vector) in which one should move from the first in order to get closer to the second. Ignores obstacles. Of several equally good directions (in the chessboard metric) it picks one of those that visually (in the euclidean metric) maximally align with the vector between the two points.