hex

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 Go to latest Published: Feb 6, 2017 License: MIT Imports: 9 Imported by: 0

README

What's this?

This is a Go library for 2D hex grids.

It should be especially suitable for implementing games played on hex grids.

It contains:

  • Basic types and operations on them: * Hex coordinates * Hex directions * Hex coordinate sets
  • A shadowcasting algorithm (for field-of-view)
  • Protobuf equivalents of the above types
  • A couple of searching algorithms:
    • BFS
    • DFS
    • A*

I (@steinarvk) hold the copyright on this code. It is not associated with any employer of mine, past or present.

The code is made available for use under the MIT license; see the LICENSE file for details.

Documentation

Index

Constants

View Source 
const (
	North     HexDir = iota
	Northwest        = iota
	Southwest        = iota
	South            = iota
	Southeast        = iota
	Northeast        = iota
)

Variables

View Source 
var (
	// FullAngularInterval is the AngularInterval that contains all angles.
	FullAngularInterval = AngularInterval{Full: true}

	// EmptyAngularInterval is the AngularInterval that contains no angles.
	EmptyAngularInterval = AngularInterval{Empty: true}
)
View Source 
var (
	OrderedDirections = []HexDir{
		North, Northwest, Southwest, South, Southeast, Northeast,
	}

	OrthogonalCCW = map[HexDir]HexDir{
		North:     Southwest,
		Northwest: South,
		Southwest: Southeast,
		South:     Northeast,
		Southeast: North,
		Northeast: Northwest,
	}

	Directions = map[HexDir]HexCoord{
		North:     HexCoord{0, 2},
		Northwest: HexCoord{-1, 1},
		Southwest: HexCoord{-1, -1},
		South:     HexCoord{0, -2},
		Southeast: HexCoord{1, -1},
		Northeast: HexCoord{1, 1},
	}

	Origin = HexCoord{0, 0}
)

Functions

func DirectionToProto 

func DirectionToProto(d HexDir) pb.Direction

DirectionToProto converts a HexDir to a pb.Direction.

func HexCircumference 

func HexCircumference(r int) int

HexCircumference computes the circumference (in number of cells) of a hex "circle" of radius r, where with the degenerate case of r=0 representing a single cell.

func IsFullyConnected 

func IsFullyConnected(s *HexSet) bool

IsFullyConnected checks whether a HexSet is fully connected.

Types

type AStarParams 

type AStarParams struct {
	Start     *HexSet
	IsGoal    func(HexCoord) bool
	Cost      func(HexCoord, HexCoord) (float64, bool)
	Heuristic func(HexCoord) float64
	MaxCost   float64
}

AStarParams provides parameters for an A* search.

type AStarResult 

type AStarResult struct {
	Path []HexCoord
	Cost float64
}

AStarResult represents the result of an A* search.

func AStar 

func AStar(params *AStarParams) (*AStarResult, error)

AStar performs an A* search.

type AngularInterval 

type AngularInterval struct {
	Empty, Full bool
	Rad0, Rad1  float64
}

AngularInterval is a connected interval of angles.

func NewAngularInterval 

func NewAngularInterval(a0, a1 float64) AngularInterval

NewAngularInterval constructs a new angular interval -- neither empty nor full.

func NewAngularSextant 

func NewAngularSextant(section HexDir) AngularInterval

NewAngularSextant computes an AngularInterval corresponding to a given sextant (i.e. 60-degree section of the plane corresponding to the hex directions outwards from the origin).

func (AngularInterval) Contains 

func (n AngularInterval) Contains(a float64) bool

Contains tests whether another AngularInterval is contained in this one.

func (AngularInterval) Intersection 

func (n AngularInterval) Intersection(x AngularInterval) AngularInterval

Intersection computes the intersection of two AngularIntervals.

func (AngularInterval) Size 

func (n AngularInterval) Size() float64

Size returns the size (in radians) of an angular interval.

func (AngularInterval) String 

func (n AngularInterval) String() string

String returns a human-readable string form of an AngularInterval.

type GeoCoord 

type GeoCoord struct {
	X, Y float64
}

GeoCoord is a geometric coordinate (a general coordinate on the 2D plane, not restricted to the hex grid).

func NewGeoPolar 

func NewGeoPolar(r float64, a float64) GeoCoord

NewGeoPolar creates a GeoCoord, specified with polar coordinates.

func (GeoCoord) Add 

func (g GeoCoord) Add(g2 GeoCoord) GeoCoord

Add adds two GeoCoords.

func (GeoCoord) Angle 

func (g GeoCoord) Angle() float64

Angle converts a GeoCoord to an angle (from the origin).

func (GeoCoord) Cross 

func (c GeoCoord) Cross(v GeoCoord) float64

GeoCoord computes the cross product of this GeoCoord with another.

func (GeoCoord) DistanceTo 

func (g GeoCoord) DistanceTo(g2 GeoCoord) float64

DistanceTo computes the distance between two GeoCoords.

func (GeoCoord) Length 

func (g GeoCoord) Length() float64

Length computes the distance of a GeoCoord from the origin.

func (GeoCoord) Normalized 

func (c GeoCoord) Normalized() GeoCoord

Normalized produces a new GeoCoord that is a normalized version of the old one.

func (GeoCoord) Scaled 

func (c GeoCoord) Scaled(s float64) GeoCoord

Scaled produces a new GeoCoord that is a scaled version of the old one.

func (GeoCoord) SquareLength 

func (g GeoCoord) SquareLength() float64

SquareLength computes the squared length of a GeoCoord (the squared distance from the origin).

func (GeoCoord) String 

func (p GeoCoord) String() string

String returns a human-readable string form of a GeoCoord.

func (GeoCoord) Sub 

func (g GeoCoord) Sub(g2 GeoCoord) GeoCoord

Sub subtracts two GeoCoords.

type HexCoord 

type HexCoord struct {
	X, Y int
}

HexCoord is a coordinate on a hex grid. (X,Y) is a valid hex coordinate if and only if X and Y are of equal parity.

func BreadthFirstSearch 

func BreadthFirstSearch(start HexCoord, isSteppable func(HexCoord, HexCoord) bool, isGoal func(HexCoord) bool) ([]HexCoord, error)

BreadthFirstSearch runs a breadth-first search through a hex grid. The hex grid is specified through the two functions "isSteppable" (which determines whether a step from one coordinate to another is legal) and "isGoal" (which determines whether the goal has been reached).

func BreadthFirstSearchFromMultiple 

func BreadthFirstSearchFromMultiple(frontierSet *HexSet, isSteppable func(HexCoord, HexCoord) bool, isGoal func(HexCoord) bool) ([]HexCoord, error)

BreadthFirstSearchFromMultiple performs a breadth-first search (like BreadthFirstSearch), except starting from multiple coordinates at once.

func DepthFirstSearch 

func DepthFirstSearch(start HexCoord, isSteppable func(HexCoord, HexCoord) bool, isGoal func(HexCoord) bool) ([]HexCoord, error)

DepthFirstSearch performs a depth-first search on a hex grid. Like BreadthFirstSearch, the hex grid is specified through callback functions "isSteppable" and "isGoal".

func HexCircle 

func HexCircle(r int) []HexCoord

HexCircle computes a slice of all the HexCoords at a certain radius.

func HexDisk 

func HexDisk(r int) []HexCoord

HexDisk computes a slice of all the HexCoords at or below a certain radius.

func HexFromProto 

func HexFromProto(p *pb.HexCoord) (HexCoord, error)

HexFromProto converts a proto to a HexCoord.

func NewHex 

func NewHex(x, y int) HexCoord

NewHex creates a new HexCoord, without checking that it is valid.

func NewHexPolar 

func NewHexPolar(r, step int) HexCoord

NewHexPolar computes a HexCoord using integral polar coordinates.

func RandomHexOnCircle 

func RandomHexOnCircle(r *rand.Rand, radius int) HexCoord

RandomHexOnCircle returns a random hex on a "hex circle".

func RayIntersection 

func RayIntersection(start, delta HexCoord, set *HexSet) (HexCoord, error)

RayIntersection finds the first intersection of a ray (where the direction is cell-aligned) with a HexSet. An error is returned if no intersection exists.

func TryNewHex 

func TryNewHex(x, y int) (HexCoord, error)

TryNewHex creates a new HexCoord, returning an error if the two integers do not specify a valid coordinate (i.e. are not of equal parity).

func (*HexCoord) AbsX 

func (c *HexCoord) AbsX() int

AbsX returns the absolute value of the HexCoord's X coordinate.

func (*HexCoord) AbsY 

func (c *HexCoord) AbsY() int

AbsY returns the absolute value of the HexCoord's Y coordinate.

func (*HexCoord) AddDelta 

func (c *HexCoord) AddDelta(d HexCoord) HexCoord

AddDelta adds two HexCoords.

func (*HexCoord) AddMultDelta 

func (c *HexCoord) AddMultDelta(m int, d HexCoord) HexCoord

AddMultDelta adds a multiple of a HexCoord; i.e. c + m * d.

func (HexCoord) CalculateFov 

func (c HexCoord) CalculateFov(cone AngularInterval, maxR int, obstruct func(HexCoord) bool, addLight func(HexCoord, AngularInterval))

CalculateFov calculates shadowcasting field-of-view from the origin. FOV may be restricted by angle or by radius (use -1) to not restrict by radius. Obstructions are specified through the "obstruct" callback. Output happens with the "addLight" callback which adds light to a certain HexCoord. Note that addLight can be called multiple times for one HexCoord.

func (HexCoord) ContainsRay 

func (c HexCoord) ContainsRay(dx, dy float64) bool

ContainsRay tests whether the hex would intersect a given ray from the origin.

func (HexCoord) ExtremeAngles 

func (c HexCoord) ExtremeAngles() AngularInterval

ExtremeAngles computes the AngularInterval of this hexagon seen from the origin.

func (HexCoord) Geo 

func (c HexCoord) Geo() GeoCoord

Geo finds the GeoCoord representing the center of the given HexCoord.

func (HexCoord) IsZero 

func (c HexCoord) IsZero() bool

IsZero tests whether a HexCoord is the origin.

func (HexCoord) Less 

func (a HexCoord) Less(b HexCoord) bool

Less computes a lexicographic ordering of HexCoords.

func (HexCoord) Minus 

func (c HexCoord) Minus(p HexCoord) HexCoord

Minus subtracts two HexCoords.

func (*HexCoord) Move 

func (c *HexCoord) Move(ds ...HexDir) HexCoord

Move computes a HexCoord that results after taking an number of steps from an initial HexCoord.

func (HexCoord) Negation 

func (c HexCoord) Negation() HexCoord

Negation computes the negation of the HexCoord (i.e. scaled by -1).

func (*HexCoord) Neighbours 

func (c *HexCoord) Neighbours() []HexCoord

Neighbours computes a slice of the HexCoord's immediate neighbours.

func (*HexCoord) NeighboursSet 

func (c *HexCoord) NeighboursSet() *HexSet

NeighboursSet computes the HexSet of a HexCoord's immediate neighbours.

func (*HexCoord) Radius 

func (c *HexCoord) Radius() int

Radius computes the radius of the HexCoord.

func (HexCoord) String 

func (c HexCoord) String() string

String computes a human-readable string form of a HexCoord.

func (HexCoord) ToProto 

func (c HexCoord) ToProto() *pb.HexCoord

ToProto converts a HexCoord to a proto.

func (HexCoord) Vertex 

func (c HexCoord) Vertex(i int) GeoCoord

Vertex finds the GeoCoord at the i'th corner vertex of the hexagon. i=0 is the east vertex (k,0) from the center, and the vertices proceed counterclockwise around the hexagon.

type HexDir 

type HexDir int32

HexDir represents one of the six directions on a hex grid.

func DirectionFromProto 

func DirectionFromProto(d pb.Direction) HexDir

DirectionFromProto converts a pb.Direction to a HexDir.

type HexSet 

type HexSet struct {
	// contains filtered or unexported fields
}

HexSet is a set of HexCoords.

func FindConnectedComponent 

func FindConnectedComponent(start HexCoord, isContained func(HexCoord) bool) (*HexSet, error)

FindConnectedComponent determines, given a representative coordinate and a membership-test function, the connected component of the representative.

func HexSetFromProto 

func HexSetFromProto(p *pb.HexSet) (*HexSet, error)

HexSetFromProto converts a pb.HexSet proto to a HexSet.

func HexSetWithHolesFilled 

func HexSetWithHolesFilled(s *HexSet) *HexSet

HexSetWithHolesFilled returns a HexSet with any internal holes filled.

func NewHexSet 

func NewHexSet() *HexSet

NewHexSet creates a new (empty and unfrozen) HexSet.

func NewHexSetAround 

func NewHexSetAround(p HexCoord, r int) *HexSet

NewHexSetAround creates a new HexSet containing one HexCoord and all HexCoords within a certain radius of it.

func NewHexSetSingleton 

func NewHexSetSingleton(p HexCoord) *HexSet

NewHexSetSingleton creates a new HexSet containing a single HexCoord.

func (*HexSet) Add 

func (h *HexSet) Add(x HexCoord)

Add adds a HexCoord to the HexSet.

func (*HexSet) AddHex 

func (h *HexSet) AddHex(i, j int)

RemoveHex adds a certain HexCoord (specified explicitly with integers) to the HexSet.

func (*HexSet) Clone 

func (h *HexSet) Clone() *HexSet

Clone makes a clone of a HexSet.

func (*HexSet) Contains 

func (h *HexSet) Contains(x HexCoord) bool

Contains checks whether a HexSet contains a certain HexCoord.

func (*HexSet) ContainsHex 

func (h *HexSet) ContainsHex(i, j int) bool

ContainsHex checks whether a certain HexCoord (specified explicitly with integers) is in the HexSet.

func (*HexSet) ContainsSet 

func (h *HexSet) ContainsSet(xs *HexSet) bool

ContainsSet checks whether a HexSet contains an entire other set.

func (*HexSet) Difference 

func (h *HexSet) Difference(x *HexSet) *HexSet

Difference removes all elements in another HexSet from this HexSet.

func (*HexSet) Each 

func (h *HexSet) Each(f func(HexCoord))

Each runs a callback on each of the HexCoords in a HexSet.

func (*HexSet) Enumerate 

func (h *HexSet) Enumerate() []HexCoord

Enumerate converts a HexSet to a slice of HexCoords.

func (*HexSet) Except 

func (h *HexSet) Except(p HexCoord) *HexSet

Except computes a new HexSet that is like this one, except not containing a certain HexCoord.

func (*HexSet) Expand 

func (h *HexSet) Expand(n int)

Expand expands the HexSet n steps outward from each coordinate.

func (*HexSet) ExpandFiltered 

func (h *HexSet) ExpandFiltered(n int, f func(HexCoord) bool)

ExpandFiltered expands the HexSet n steps outwards; except not proceeding into any hex p where f(p) return false.

func (*HexSet) Expanded 

func (h *HexSet) Expanded(n int) *HexSet

Expanded computes a new HexSet that is like the old one, except expanded by n steps.

func (*HexSet) Filter 

func (h *HexSet) Filter(f func(HexCoord) bool)

Filter removes any point p from the HexSet where f(p) returns false.

func (*HexSet) Filtered 

func (h *HexSet) Filtered(f func(HexCoord) bool) *HexSet

Filtered computes a new HexSet that is like the old one, except only containing HexCoords p where f(p) returns true.

func (*HexSet) Freeze 

func (s *HexSet) Freeze()

Freeze marks the HexSet as immutable.

func (*HexSet) GeoDistanceHeuristic 

func (c *HexSet) GeoDistanceHeuristic() func(HexCoord) float64

GeoDistanceHeuristic returns a function f(x) that, given a HexCoord x, computes the minimum geometric distance to any point p in the HexSet.

func (*HexSet) GoRepr 

func (s *HexSet) GoRepr() string

GoRepr returns an explicit Go representation of the HexSet (code that would produce it).

func (*HexSet) InPlaceUnion 

func (h *HexSet) InPlaceUnion(x *HexSet)

InPlaceUnion mutates the HexSet to take the union with another.

func (*HexSet) Intersection 

func (h *HexSet) Intersection(x *HexSet) *HexSet

Intersection computes the intersection of two HexSets.

func (*HexSet) Intersects 

func (h *HexSet) Intersects(x *HexSet) bool

Intersects checks whether two HexSets intersect.

func (*HexSet) IntersectsWithOffset 

func (h *HexSet) IntersectsWithOffset(x *HexSet, offset HexCoord) bool

IntersectsWithOffset checks whether a HexSet intersects with the result of mapping over another by (+offset), i.e. adding a certain HexCoord delta to each element.

func (*HexSet) MaxRadius 

func (h *HexSet) MaxRadius() int

MaxRadius returns an upper bound on the radius of the HexCoords in the set.

func (*HexSet) OuterBorder 

func (s *HexSet) OuterBorder() *HexSet

OuterBorder computes the outer border of the HexSet.

func (*HexSet) PickArbitrary 

func (h *HexSet) PickArbitrary() (HexCoord, error)

PickArbitrary picks an arbitrary HexCoord from a HexSet.

func (*HexSet) Predicate 

func (c *HexSet) Predicate() func(HexCoord) bool

Predicate converts the HexSet to a callback that checks for HexCoord membership in the set.

func (*HexSet) Random 

func (h *HexSet) Random() (HexCoord, error)

Random selects a random HexCoord from a HexSet.

func (*HexSet) RandomFrom 

func (h *HexSet) RandomFrom(r *rand.Rand) (HexCoord, error)

RandomFrom selects a random HexCoord from a HexSet, using a specified rand.Rand.

func (*HexSet) Remove 

func (h *HexSet) Remove(x HexCoord)

Remove removes a HexCoord from the HexSet.

func (*HexSet) RemoveHex 

func (h *HexSet) RemoveHex(i, j int)

RemoveHex removes a certain HexCoord (specified explicitly with integers) from the HexSet.

func (*HexSet) Size 

func (h *HexSet) Size() int

Size returns the number of elements in the HexSet.

func (*HexSet) ToList 

func (h *HexSet) ToList() []HexCoord

ToList converts a HexSet to a list of HexCoords.

func (*HexSet) ToOrderedList 

func (h *HexSet) ToOrderedList() []HexCoord

ToOrderedList converts a HexSet to an ordered list of HexCoords.

func (*HexSet) ToProto 

func (c *HexSet) ToProto() *pb.HexSet

ToProto converts a HexSet to a pb.HexSet proto.

func (*HexSet) Union 

func (h *HexSet) Union(x *HexSet) *HexSet

Union computes a new HexSet that is like this one union'd with another.

Source Files

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Directories

Path Synopsis
Package hexpb is a generated protocol buffer package.
 Package hexpb is a generated protocol buffer package.

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