ml
42 lines
1.1 KiB
Go
42 lines
1.1 KiB
Go
package level
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// Direction is an enumeration of cardinal and ordinal directions.
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// Cardinal directions describe sides, ordinal directions describe corners.
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type Direction byte
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// Plus is a shortcut for dir.AsMask().Plus(other).
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func (dir Direction) Plus(other Direction) DirectionMask {
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return dir.AsMask().Plus(other)
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}
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// AsMask returns the direction as a mask.
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func (dir Direction) AsMask() DirectionMask {
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return DirectionMask(1 << dir)
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}
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// Offset returns a direction that you reach by offsetting this one by the given value.
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// The direction goes in a circle, and both positive and negative offsets are allowed.
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func (dir Direction) Offset(offset int) Direction {
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return Direction((int(dir) + ((8 + (offset % 8)) % 8)) % 8)
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}
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// DirectionMask is a bitfield combination of directions.
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type DirectionMask byte
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// Plus adds the mask of the given direction to this mask and returns the result.
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func (mask DirectionMask) Plus(dir Direction) DirectionMask {
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return mask | dir.AsMask()
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}
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// Direction constants are listed below.
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const (
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DirNorth Direction = iota
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DirNorthEast
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DirEast
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DirSouthEast
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DirSouth
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DirSouthWest
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DirWest
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DirNorthWest
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)
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