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>

Theriapolis.Game/Rendering/TileAtlas.cs

@@ -0,0 +1,139 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+using Theriapolis.Core.Data;
+using Theriapolis.Core.World;
+
+namespace Theriapolis.Game.Rendering;
+
+/// <summary>
+/// Manages the biome tile textures used by the world-map renderer.
+/// For Phase 0/1, all tiles are generated at runtime as flat-colour 32×32 squares
+/// with a 1px darker border and a single centered letter.
+/// Final art will replace these by swapping file contents; no code changes needed.
+/// </summary>
+public sealed class TileAtlas : IDisposable
+{
+    private readonly GraphicsDevice _gd;
+    private readonly Dictionary<BiomeId, Texture2D> _textures = new();
+    private readonly Dictionary<int, Texture2D> _settlementIcons = new(); // keyed by tier
+    private SpriteFont? _font;
+    private bool _disposed;
+
+    public GraphicsDevice GraphicsDevice => _gd;
+
+    // Fallback solid-color texture for any biome that has no dedicated entry
+    private Texture2D? _fallback;
+
+    public TileAtlas(GraphicsDevice gd)
+    {
+        _gd = gd;
+    }
+
+    /// <summary>
+    /// Generate all placeholder textures from the loaded BiomeDef array.
+    /// Call once after content is loaded.
+    /// </summary>
+    public void GeneratePlaceholders(BiomeDef[] biomes, SpriteFont? font = null)
+    {
+        _font = font;
+        foreach (var def in biomes)
+        {
+            var biomeId = BiomeAssignHelper.ParseBiomeId(def.Id);
+            if (_textures.ContainsKey(biomeId)) continue;
+            _textures[biomeId] = MakeTile(def);
+        }
+        _fallback = MakeSolidColor(Color.HotPink); // obvious "missing art" colour
+        GenerateSettlementIcons();
+    }
+
+    /// <summary>Returns the settlement icon texture for the given tier (1–5).</summary>
+    public Texture2D GetSettlementIcon(int tier)
+    {
+        if (_settlementIcons.TryGetValue(tier, out var tex)) return tex;
+        return _fallback ?? _textures.Values.First();
+    }
+
+    private void GenerateSettlementIcons()
+    {
+        // Tier 1: large gold diamond (capital)
+        _settlementIcons[1] = MakeSettlementIcon(20, new Color(255, 215, 0), diamond: true);
+        // Tier 2: white square (city)
+        _settlementIcons[2] = MakeSettlementIcon(14, new Color(230, 230, 230), diamond: false);
+        // Tier 3: light-blue circle (town)
+        _settlementIcons[3] = MakeSettlementIcon(10, new Color(150, 200, 255), diamond: false);
+        // Tier 4: pale dot (village)
+        _settlementIcons[4] = MakeSettlementIcon(6,  new Color(200, 200, 200), diamond: false);
+        // Tier 5 (PoI): small red circle
+        _settlementIcons[5] = MakeSettlementIcon(5,  new Color(200, 60, 60),   diamond: false);
+    }
+
+    private Texture2D MakeSettlementIcon(int size, Color fill, bool diamond)
+    {
+        var tex    = new Texture2D(_gd, size, size);
+        var pixels = new Color[size * size];
+        float cx   = (size - 1) * 0.5f;
+        float cy   = (size - 1) * 0.5f;
+
+        for (int py = 0; py < size; py++)
+        for (int px = 0; px < size; px++)
+        {
+            float nx = px - cx, ny = py - cy;
+            bool inside = diamond
+                ? (MathF.Abs(nx) + MathF.Abs(ny)) <= size * 0.5f
+                : (nx * nx + ny * ny) <= (cx * cx);
+            pixels[py * size + px] = inside ? fill : Color.Transparent;
+        }
+
+        tex.SetData(pixels);
+        return tex;
+    }
+
+    /// <summary>Returns the texture for the given biome, falling back to the error texture.</summary>
+    public Texture2D GetTile(BiomeId biome)
+    {
+        if (_textures.TryGetValue(biome, out var tex)) return tex;
+        return _fallback ?? _textures.Values.First();
+    }
+
+    // ── Texture generation helpers ────────────────────────────────────────────
+
+    private Texture2D MakeTile(BiomeDef def)
+    {
+        int size = Theriapolis.Core.C.WORLD_TILE_PIXELS;
+        var (r, g, b) = def.ParsedColor();
+        var fillColor = new Color(r, g, b);
+
+        var tex    = new Texture2D(_gd, size, size);
+        var pixels = new Color[size * size];
+        Array.Fill(pixels, fillColor);
+
+        tex.SetData(pixels);
+        return tex;
+    }
+
+    private Texture2D MakeSolidColor(Color color)
+    {
+        int size   = Theriapolis.Core.C.WORLD_TILE_PIXELS;
+        var tex    = new Texture2D(_gd, size, size);
+        var pixels = new Color[size * size];
+        Array.Fill(pixels, color);
+        tex.SetData(pixels);
+        return tex;
+    }
+
+    public void Dispose()
+    {
+        if (_disposed) return;
+        _disposed = true;
+        foreach (var tex in _textures.Values) tex.Dispose();
+        foreach (var tex in _settlementIcons.Values) tex.Dispose();
+        _fallback?.Dispose();
+    }
+}
+
+/// <summary>Internal helper to avoid exposing the private static method on BiomeAssignStage.</summary>
+internal static class BiomeAssignHelper
+{
+    public static BiomeId ParseBiomeId(string id)
+        => Theriapolis.Core.World.Generation.Stages.BiomeAssignStage.ParseBiomeId(id);
+}