RPG world mod: tile maps, grid walking, map events, battles

Maps of square tiles in three layers plus a collision layer, mounted over
the 2D shell when their scene is entered. WASD walking, E/F action events,
touch teleports, story-flag conditions, random encounters, rpg.battle and
rpg.teleport actions, position saving. Integration suite rpg_walk.

src/Data/RpgMapEvent.cs

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+using System.Collections.Generic;
+
+namespace Cthangover.Mods.Rpg
+{
+    /// <summary>
+    /// Something placed on a map cell that reacts to the player, in the spirit of
+    /// RPG Maker events: an NPC, a sign, a chest, a door. What it looks like and
+    /// what it does are independent:
+    /// <list type="bullet">
+    /// <item>look — a charset <see cref="Sprite"/>, or one atlas <see cref="Tile"/>, or nothing (an invisible trigger);</item>
+    /// <item>effect — a <see cref="Teleport"/>, handled natively, or a dialog built
+    /// from a <see cref="Scenario"/> file followed by inline <see cref="Commands"/>
+    /// (the full scenario DSL, so <c>action rpg.battle …</c>, <c>flag …</c>, quests).</item>
+    /// </list>
+    /// A <see cref="Condition"/> in the scenario condition language hides the
+    /// event while false; it is re-checked whenever game state changes, so a
+    /// defeated boss (<c>flag boss_dead 1</c>) disappears at once.
+    /// </summary>
+    public class RpgMapEvent
+    {
+        /// <summary>Id unique within the map.</summary>
+        public string Id { get; set; }
+
+        /// <summary>Column.</summary>
+        public int X { get; set; }
+
+        /// <summary>Row.</summary>
+        public int Y { get; set; }
+
+        /// <summary>Charset image in the <c>charsets</c> group (3 frames × 4 facings).</summary>
+        public string Sprite { get; set; }
+
+        /// <summary>Atlas index of the map's tileset drawn as the event when it has no sprite; -1 for none.</summary>
+        public int Tile { get; set; } = -1;
+
+        /// <summary>Initial facing of a sprite.</summary>
+        public RpgDirection Dir { get; set; } = RpgDirection.Down;
+
+        /// <summary>When the event fires.</summary>
+        public RpgEventTrigger Trigger { get; set; } = RpgEventTrigger.Action;
+
+        /// <summary>The event occupies its cell. Null means "solid when it is visible" (a sprite or a tile).</summary>
+        public bool? Solid { get; set; }
+
+        /// <summary>Scenario path inside the <c>scenarios</c> group (extension optional), played as a dialog.</summary>
+        public string Scenario { get; set; }
+
+        /// <summary>Inline DSL lines appended after the scenario.</summary>
+        public List<string> Commands { get; set; }
+
+        /// <summary>Moves the player instead of starting a dialog.</summary>
+        public RpgTeleport Teleport { get; set; }
+
+        /// <summary>Scenario condition; the event exists only while it is true.</summary>
+        public string Condition { get; set; }
+
+        /// <summary>Effective solidity: explicit value, else whether the event is drawn.</summary>
+        public bool IsSolid => Solid ?? (!string.IsNullOrEmpty(Sprite) || Tile >= 0);
+    }
+}