Files
OpenRA/OpenRA.Mods.Common/MapGenerator/Direction.cs
2025-03-31 12:02:41 +03:00

297 lines
7.6 KiB
C#

#region Copyright & License Information
/*
* Copyright (c) The OpenRA Developers and Contributors
* This file is part of OpenRA, which is free software. It is made
* available to you under the terms of the GNU General Public License
* as published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version. For more
* information, see COPYING.
*/
#endregion
using System;
using System.Collections.Immutable;
using System.Linq;
namespace OpenRA.Mods.Common.MapGenerator
{
/// <summary>
/// Utilities for simple directions and adjacency. Note that coordinate systems might not agree
/// as to which directions are conceptually left/right or up/down.
/// </summary>
public static class Direction
{
/// <summary>No direction.</summary>
public const int None = -1;
/// <summary>+X ("right").</summary>
public const int R = 0;
/// <summary>+X+Y ("right down").</summary>
public const int RD = 1;
/// <summary>+Y ("down").</summary>
public const int D = 2;
/// <summary>-X+Y ("left down").</summary>
public const int LD = 3;
/// <summary>-X ("left").</summary>
public const int L = 4;
/// <summary>-X-Y ("left up").</summary>
public const int LU = 5;
/// <summary>-Y ("up").</summary>
public const int U = 6;
/// <summary>+X-Y ("right up").</summary>
public const int RU = 7;
/// <summary>Bitmask right.</summary>
public const int MR = 1 << R;
/// <summary>Bitmask right-down.</summary>
public const int MRD = 1 << RD;
/// <summary>Bitmask down.</summary>
public const int MD = 1 << D;
/// <summary>Bitmask left-down.</summary>
public const int MLD = 1 << LD;
/// <summary>Bitmask left.</summary>
public const int ML = 1 << L;
/// <summary>Bitmask left-up.</summary>
public const int MLU = 1 << LU;
/// <summary>Bitmask up.</summary>
public const int MU = 1 << U;
/// <summary>Bitmask right-up.</summary>
public const int MRU = 1 << RU;
/// <summary>Adjacent offsets with directions, excluding diagonals.</summary>
public static readonly ImmutableArray<(int2, int)> Spread4D =
[
(new int2(1, 0), R),
(new int2(0, 1), D),
(new int2(-1, 0), L),
(new int2(0, -1), U)
];
/// <summary>Adjacent offsets, excluding diagonals.</summary>
public static readonly ImmutableArray<int2> Spread4 =
Spread4D.Select(((int2 XY, int _) v) => v.XY).ToImmutableArray();
/// <summary>
/// Adjacent offsets, excluding diagonals. Assumes that CVec(1, 0)
/// corresponds to Direction.R.
/// </summary>
public static readonly ImmutableArray<CVec> Spread4CVec =
Spread4.Select(xy => new CVec(xy.X, xy.Y)).ToImmutableArray();
/// <summary>Adjacent offsets with directions, including diagonals.</summary>
public static readonly ImmutableArray<(int2, int)> Spread8D =
[
(new int2(1, 0), R),
(new int2(1, 1), RD),
(new int2(0, 1), D),
(new int2(-1, 1), LD),
(new int2(-1, 0), L),
(new int2(-1, -1), LU),
(new int2(0, -1), U),
(new int2(1, -1), RU)
];
/// <summary>Adjacent offsets, including diagonals.</summary>
public static readonly ImmutableArray<int2> Spread8 =
Spread8D.Select(((int2 XY, int _) v) => v.XY).ToImmutableArray();
/// <summary>
/// Adjacent offsets, including diagonals. Assumes that CVec(1, 0)
/// corresponds to Direction.R.
/// </summary>
public static readonly ImmutableArray<CVec> Spread8CVec =
Spread8.Select(xy => new CVec(xy.X, xy.Y)).ToImmutableArray();
/// <summary>Convert a non-none direction to an int2 offset.</summary>
public static int2 ToInt2(int d)
{
if (d >= 0 && d < 8)
return Spread8[d];
else
throw new ArgumentException("bad direction");
}
/// <summary>
/// Convert a non-none direction to a CVec offset. Assumes that
/// CVec(1, 0) corresponds to Direction.R.
/// </summary>
public static CVec ToCVec(int d)
{
if (d >= 0 && d < 8)
return Spread8CVec[d];
else
throw new ArgumentException("bad direction");
}
/// <summary>
/// Convert an offset (of arbitrary non-zero magnitude) to a direction.
/// Supplying a zero-offset will throw.
/// </summary>
public static int FromOffset(int dx, int dy)
{
if (dx > 0)
{
if (dy > 0)
return RD;
else if (dy < 0)
return RU;
else
return R;
}
else if (dx < 0)
{
if (dy > 0)
return LD;
else if (dy < 0)
return LU;
else
return L;
}
else
{
if (dy > 0)
return D;
else if (dy < 0)
return U;
else
throw new ArgumentException("Bad direction");
}
}
/// <summary>
/// Convert an offset (of arbitrary non-zero magnitude) to a direction.
/// Supplying a zero-offset will throw.
/// </summary>
public static int FromInt2(int2 delta)
=> FromOffset(delta.X, delta.Y);
/// <summary>
/// Convert an offset (of arbitrary non-zero magnitude) to a direction.
/// Supplying a zero-offset will throw. Assumes that CVec(1, 0)
/// corresponds to Direction.R.
/// </summary>
public static int FromCVec(CVec delta)
=> FromOffset(delta.X, delta.Y);
/// <summary>
/// Convert an offset (of arbitrary non-zero magnitude) to a non-diagonal direction.
/// Supplying a zero-offset will throw.
/// </summary>
public static int FromOffsetNonDiagonal(int dx, int dy)
{
if (dx - dy > 0 && dx + dy >= 0)
return R;
if (dy + dx > 0 && dy - dx >= 0)
return D;
if (-dx + dy > 0 && -dx - dy >= 0)
return L;
if (-dy - dx > 0 && -dy + dx >= 0)
return U;
throw new ArgumentException("bad direction");
}
/// <summary>
/// Convert an offset (of arbitrary non-zero magnitude) to a
/// non-diagonal direction. Supplying a zero-offset will throw.
/// </summary>
public static int FromInt2NonDiagonal(int2 delta)
=> FromOffsetNonDiagonal(delta.X, delta.Y);
/// <summary>
/// Convert an offset (of arbitrary non-zero magnitude) to a
/// non-diagonal direction. Supplying a zero-offset will throw. Assumes
/// that CVec(1, 0) corresponds to Direction.R.
/// </summary>
public static int FromCVecNonDiagonal(CVec delta)
=> FromOffsetNonDiagonal(delta.X, delta.Y);
/// <summary>Return the opposite direction.</summary>
public static int Reverse(int direction)
{
if (direction == None)
return None;
return direction ^ 4;
}
/// <summary>Convert a direction to a short string, like "None", "R", "RD", etc.</summary>
public static string ToString(int direction)
{
switch (direction)
{
case None: return "None";
case R: return "R";
case RD: return "RD";
case D: return "D";
case LD: return "LD";
case L: return "L";
case LU: return "LU";
case U: return "U";
case RU: return "RU";
default: throw new ArgumentException("bad direction");
}
}
/// <summary>Count the number of set bits in a direction mask.</summary>
public static int Count(int dm)
{
var count = 0;
for (var m = dm; m != 0; m >>= 1)
if ((m & 1) == 1)
count++;
return count;
}
/// <summary>Finds the only direction set in a direction mask or returns NONE.</summary>
public static int FromMask(int mask)
{
switch (mask)
{
case MR: return R;
case MRD: return RD;
case MD: return D;
case MLD: return LD;
case ML: return L;
case MLU: return LU;
case MU: return U;
case MRU: return RU;
default: return None;
}
}
/// <summary>True if diagonal, false if horizontal/vertical, throws otherwise.</summary>
public static bool IsDiagonal(int direction)
{
switch (direction)
{
case R:
case D:
case L:
case U:
return false;
case RD:
case LD:
case LU:
case RU:
return true;
default:
throw new ArgumentException("NONE or bad direction");
}
}
}
}