fix: Fixing animation optimization issue

When a tile was used several times in the same animation, it would be improperly
renumbered if the tile was already optimized before.
This prevented animations going back and forth to work correctly.

Author: moufmouf

src/Optimizer.ts

@@ -12,7 +12,11 @@ sharp.cache(false);
 
 export class Optimizer {
     private optimizedMap: ITiledMap;
-    private optimizedTiles: Map<number, number>;
+    /**
+     * A map mapping the old tile id to the new tile id (global) and to the new tile id in the current tileset
+     * @private
+     */
+    private optimizedTiles: Map<number, { global: number; local: number }>;
     private optimizedTilesets: ITiledMapEmbeddedTileset[];
     private currentTilesetOptimization: ITiledMapEmbeddedTileset;
     private currentExtractedTiles: Promise<Buffer>[];
@@ -30,7 +34,7 @@ export class Optimizer {
         private readonly outputPath: string
     ) {
         this.optimizedMap = map;
-        this.optimizedTiles = new Map<number, number>();
+        this.optimizedTiles = new Map<number, { global: number; local: number }>();
         this.optimizedTilesets = [];
         this.tileSize = options?.tile?.size ?? 32;
         this.outputSize = options?.output?.tileset?.size ? options?.output?.tileset?.size : 512;
@@ -219,7 +223,7 @@ export class Optimizer {
 
         const unflippedTileId = tileId - minBitId;
 
-        const existantNewTileId = this.optimizedTiles.get(unflippedTileId);
+        const existantNewTileId = this.optimizedTiles.get(unflippedTileId)?.global;
 
         if (existantNewTileId) {
             return existantNewTileId + minBitId;
@@ -265,7 +269,10 @@ export class Optimizer {
             if (tileData && tileData.animation) {
                 if (tileData.animation.length + this.currentExtractedTiles.length > this.tilesetMaxTileCount) {
                     for (let i = 1; i < this.tilesetMaxTileCount - this.currentExtractedTiles.length; i++) {
-                        this.optimizedTiles.set(-1, this.optimizedTiles.size + i);
+                        this.optimizedTiles.set(-1, {
+                            global: this.optimizedTiles.size + i,
+                            local: 0,
+                        });
                     }
 
                     await this.currentTilesetRendering();
@@ -275,7 +282,10 @@ export class Optimizer {
 
         const newTileId = this.optimizedTiles.size + 1;
 
-        this.optimizedTiles.set(unflippedTileId, newTileId);
+        this.optimizedTiles.set(unflippedTileId, {
+            global: newTileId,
+            local: this.currentExtractedTiles.length,
+        });
 
         let newTileData: ITiledMapTile | undefined = undefined;
 
@@ -322,10 +332,14 @@ export class Optimizer {
             newTileData.animation = [];
             for (const frame of tileData.animation) {
                 await this.optimizeNewTile(oldFirstgid + frame.tileid);
+                const newTile = this.optimizedTiles.get(oldFirstgid + frame.tileid)?.local;
+                if (newTile === undefined) {
+                    throw new Error(`Undefined tile in animation for ${oldFirstgid + frame.tileid}`);
+                }
 
                 newTileData.animation.push({
                     duration: frame.duration,
-                    tileid: this.currentExtractedTiles.length - 1,
+                    tileid: newTile,
                 });
             }
         }