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MLEM/MLEM/Misc/Direction2.cs

234 lines
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9.6 KiB
C#

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
namespace MLEM.Misc {
/// <summary>
/// An enum that represents two-dimensional directions.
/// Both straight and diagonal directions are supported.
/// </summary>
public enum Direction2 {
/// <summary>
/// The up direction, or -y.
/// </summary>
Up,
/// <summary>
/// The right direction, or +x.
/// </summary>
Right,
/// <summary>
/// The down direction, or +y.
/// </summary>
Down,
/// <summary>
/// The left direction, or -x.
/// </summary>
Left,
/// <summary>
/// The up and right direction, or +x, -y.
/// </summary>
UpRight,
/// <summary>
/// The down and right direction, or +x, +y.
/// </summary>
DownRight,
/// <summary>
/// The down and left direction, or -x, +y.
/// </summary>
DownLeft,
/// <summary>
/// The up and left direction, or -x, -y.
/// </summary>
UpLeft,
/// <summary>
/// No direction.
/// </summary>
None
}
/// <summary>
/// A set of helper and extension methods for dealing with <see cref="Direction2"/>
/// </summary>
public static class Direction2Helper {
/// <summary>
/// All <see cref="Direction2"/> enum values
/// </summary>
public static readonly Direction2[] All = EnumHelper.GetValues<Direction2>().ToArray();
/// <summary>
/// The <see cref="Direction2.Up"/> through <see cref="Direction2.Left"/> directions
/// </summary>
public static readonly Direction2[] Adjacent = All.Where(IsAdjacent).ToArray();
/// <summary>
/// The <see cref="Direction2.UpRight"/> through <see cref="Direction2.UpLeft"/> directions
/// </summary>
public static readonly Direction2[] Diagonals = All.Where(IsDiagonal).ToArray();
/// <summary>
/// All directions except <see cref="Direction2.None"/>
/// </summary>
public static readonly Direction2[] AllExceptNone = All.Where(dir => dir != Direction2.None).ToArray();
/// <summary>
/// Returns if the given direction is considered an "adjacent" direction.
/// An adjacent direction is one that is not a diagonal.
/// </summary>
/// <param name="dir">The direction to query</param>
/// <returns>Whether the direction is adjacent</returns>
public static bool IsAdjacent(this Direction2 dir) {
return dir <= Direction2.Left;
}
/// <summary>
/// Returns if the given direction is considered a diagonal direction.
/// </summary>
/// <param name="dir">The direction to query</param>
/// <returns>Whether the direction is diagonal</returns>
public static bool IsDiagonal(this Direction2 dir) {
return dir >= Direction2.UpRight && dir <= Direction2.UpLeft;
}
/// <summary>
/// Returns the directional offset of a given direction.
/// The offset direction will be exactly one unit in each axis that the direction represents.
/// </summary>
/// <param name="dir">The direction whose offset to query</param>
/// <returns>The direction's offset</returns>
public static Point Offset(this Direction2 dir) {
switch (dir) {
case Direction2.Up:
return new Point(0, -1);
case Direction2.Right:
return new Point(1, 0);
case Direction2.Down:
return new Point(0, 1);
case Direction2.Left:
return new Point(-1, 0);
case Direction2.UpRight:
return new Point(1, -1);
case Direction2.DownRight:
return new Point(1, 1);
case Direction2.DownLeft:
return new Point(-1, 1);
case Direction2.UpLeft:
return new Point(-1, -1);
default:
return Point.Zero;
}
}
/// <summary>
/// Maps each direction in the given enumerable of directions to its <see cref="Offset"/>.
/// </summary>
/// <param name="directions">The direction enumerable</param>
/// <returns>The directions' offsets, in the same order as the input directions.</returns>
public static IEnumerable<Point> Offsets(this IEnumerable<Direction2> directions) {
foreach (var dir in directions)
yield return dir.Offset();
}
/// <summary>
/// Returns the opposite of the given direction.
/// For "adjacent" directions, this is the direction that points into the same axis, but the opposite sign.
/// For diagonal directions, this is the direction that points into the opposite of both the x and y axis.
/// </summary>
/// <param name="dir">The direction whose opposite to get</param>
/// <returns>The opposite of the direction</returns>
public static Direction2 Opposite(this Direction2 dir) {
switch (dir) {
case Direction2.Up:
return Direction2.Down;
case Direction2.Right:
return Direction2.Left;
case Direction2.Down:
return Direction2.Up;
case Direction2.Left:
return Direction2.Right;
case Direction2.UpRight:
return Direction2.DownLeft;
case Direction2.DownRight:
return Direction2.UpLeft;
case Direction2.DownLeft:
return Direction2.UpRight;
case Direction2.UpLeft:
return Direction2.DownRight;
default:
return Direction2.None;
}
}
/// <summary>
/// Returns the angle of the direction in radians, where <see cref="Direction2.Right"/> has an angle of 0.
/// </summary>
/// <param name="dir">The direction whose angle to get</param>
/// <returns>The direction's angle</returns>
public static float Angle(this Direction2 dir) {
var offset = dir.Offset();
return (float) Math.Atan2(offset.Y, offset.X);
}
/// <summary>
/// Rotates the given direction clockwise and returns the resulting direction.
/// </summary>
/// <param name="dir">The direction to rotate</param>
/// <param name="fortyFiveDegrees">Whether to rotate by 45 degrees. If this is false, the rotation is 90 degrees instead.</param>
/// <returns>The rotated direction</returns>
public static Direction2 RotateCw(this Direction2 dir, bool fortyFiveDegrees = false) {
switch (dir) {
case Direction2.Up:
return fortyFiveDegrees ? Direction2.UpRight : Direction2.Right;
case Direction2.Right:
return fortyFiveDegrees ? Direction2.DownRight : Direction2.Down;
case Direction2.Down:
return fortyFiveDegrees ? Direction2.DownLeft : Direction2.Left;
case Direction2.Left:
return fortyFiveDegrees ? Direction2.UpLeft : Direction2.Up;
case Direction2.UpRight:
return fortyFiveDegrees ? Direction2.Right : Direction2.DownRight;
case Direction2.DownRight:
return fortyFiveDegrees ? Direction2.Down : Direction2.DownLeft;
case Direction2.DownLeft:
return fortyFiveDegrees ? Direction2.Left : Direction2.UpLeft;
case Direction2.UpLeft:
return fortyFiveDegrees ? Direction2.Up : Direction2.UpRight;
default:
return Direction2.None;
}
}
/// <summary>
/// Rotates the given direction counter-clockwise and returns the resulting direction.
/// </summary>
/// <param name="dir">The direction to rotate counter-clockwise</param>
/// <param name="fortyFiveDegrees">Whether to rotate by 45 degrees. If this is false, the rotation is 90 degrees instead.</param>
/// <returns>The rotated direction</returns>
public static Direction2 RotateCcw(this Direction2 dir, bool fortyFiveDegrees = false) {
switch (dir) {
case Direction2.Up:
return fortyFiveDegrees ? Direction2.UpLeft : Direction2.Left;
case Direction2.Right:
return fortyFiveDegrees ? Direction2.UpRight : Direction2.Up;
case Direction2.Down:
return fortyFiveDegrees ? Direction2.DownRight : Direction2.Right;
case Direction2.Left:
return fortyFiveDegrees ? Direction2.DownLeft : Direction2.Down;
case Direction2.UpRight:
return fortyFiveDegrees ? Direction2.Up : Direction2.UpLeft;
case Direction2.DownRight:
return fortyFiveDegrees ? Direction2.Right : Direction2.UpRight;
case Direction2.DownLeft:
return fortyFiveDegrees ? Direction2.Down : Direction2.DownRight;
case Direction2.UpLeft:
return fortyFiveDegrees ? Direction2.Left : Direction2.DownLeft;
default:
return Direction2.None;
}
}
}
}