Initial commit: Theriapolis baseline at port/godot branch point

Captures the pre-Godot-port state of the codebase. This is the rollback anchor for the Godot port (M0 of theriapolis-rpg-implementation-plan-godot-port.md). All Phase 0 through Phase 6.5 work is included; Phase 7 is in flight. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-04-30 20:40:51 -07:00
commit b451f83174
525 changed files with 75786 additions and 0 deletions
@@ -0,0 +1,68 @@
+namespace Theriapolis.Core.Util;
+
+/// <summary>
+/// Direction encoding for tile-level features (rivers, rail, roads).
+/// Directions are stored as byte values 0–7, matching the 8 compass points.
+/// 255 = "no direction" / unset.
+/// </summary>
+public static class Dir
+{
+    // Direction constants (0-based, CCW from North)
+    public const byte None = 255;
+    public const byte N    = 0;   // (dx= 0, dy=-1)
+    public const byte NE   = 1;   // (dx= 1, dy=-1)
+    public const byte E    = 2;   // (dx= 1, dy= 0)
+    public const byte SE   = 3;   // (dx= 1, dy= 1)
+    public const byte S    = 4;   // (dx= 0, dy= 1)
+    public const byte SW   = 5;   // (dx=-1, dy= 1)
+    public const byte W    = 6;   // (dx=-1, dy= 0)
+    public const byte NW   = 7;   // (dx=-1, dy=-1)
+
+    private static readonly (int dx, int dy)[] _deltas =
+    {
+        ( 0,-1), ( 1,-1), ( 1, 0), ( 1, 1),
+        ( 0, 1), (-1, 1), (-1, 0), (-1,-1),
+    };
+
+    /// <summary>Convert a (dx, dy) delta to a direction byte. Both values must be in {-1,0,1}.</summary>
+    public static byte FromDelta(int dx, int dy)
+    {
+        for (byte i = 0; i < 8; i++)
+            if (_deltas[i].dx == dx && _deltas[i].dy == dy)
+                return i;
+        return None;
+    }
+
+    public static (int dx, int dy) ToDelta(byte dir)
+    {
+        if (dir == None) return (0, 0);
+        return _deltas[dir & 7];
+    }
+
+    /// <summary>
+    /// Two directions are parallel if their angular difference is ≤ 45° (including opposite directions).
+    /// </summary>
+    public static bool IsParallel(byte a, byte b)
+    {
+        if (a == None || b == None) return false;
+        int diff = Math.Abs((int)(a & 7) - (int)(b & 7));
+        diff = Math.Min(diff, 8 - diff);
+        // diff 0 = same; diff 1 = 45°; diff 4 = 180° (opposite still parallel)
+        return diff <= 1 || diff >= 3; // ≤45° or ≥135° (anti-parallel)
+    }
+
+    /// <summary>
+    /// Two directions are perpendicular if their angular difference is in [60°, 120°].
+    /// Using discrete 45° steps: diff 2 = 90°.
+    /// </summary>
+    public static bool IsPerpendicular(byte a, byte b)
+    {
+        if (a == None || b == None) return false;
+        int diff = Math.Abs((int)(a & 7) - (int)(b & 7));
+        diff = Math.Min(diff, 8 - diff);
+        return diff == 2;
+    }
+
+    /// <summary>Opposite direction.</summary>
+    public static byte Opposite(byte d) => d == None ? None : (byte)((d + 4) & 7);
+}