make char-to-terrain lookup dictionary-based instead of switch-based

GitOrigin-RevId: 0d81e95bf0

Shared/World.cs

@@ -90,6 +90,18 @@ namespace SemiColinGames {
 ====================> <====..========..======..=========..=========>  <=============>   <==============================================================>  <=======..==============..==============================
 ....................] [............................................]  [.............]   [..............................................................]  [.......................................................";
 
+    private static readonly Dictionary<char, Terrain> charToTerrain =
+        new Dictionary<char, Terrain>() {
+      { '=', Terrain.Grass },
+      { '<', Terrain.GrassL },
+      { '>', Terrain.GrassR },
+      { '.', Terrain.Rock },
+      { '[', Terrain.RockL },
+      { ']', Terrain.RockR },
+      { '~', Terrain.Water },
+      { 'X', Terrain.Block }
+    };
+
     public World(Texture2D texture) {
       var tilesList = new List<Tile>();
       string[] worldDesc = worldString.Split('\n');
@@ -98,39 +110,14 @@ namespace SemiColinGames {
       Debug.WriteLine("world size: {0}x{1}", tileWidth, tileHeight);
       for (int i = 0; i < tileWidth; i++) {
         for (int j = 0; j < tileHeight; j++) {
-          Terrain? terrain = null;
           if (i < worldDesc[j].Length) {
-            switch (worldDesc[j][i]) {
-              case '=':
-                terrain = Terrain.Grass;
-                break;
-              case '<':
-                terrain = Terrain.GrassL;
-                break;
-              case '>':
-                terrain = Terrain.GrassR;
-                break;
-              case '.':
-                terrain = Terrain.Rock;
-                break;
-              case '[':
-                terrain = Terrain.RockL;
-                break;
-              case ']':
-                terrain = Terrain.RockR;
-                break;
-              case '~':
-                terrain = Terrain.Water;
-                break;
-              case 'X':
-                terrain = Terrain.Block;
-                break;
+            char key = worldDesc[j][i];
+            if (charToTerrain.ContainsKey(key)) {
+              Terrain terrain = charToTerrain[key];
+              var position = new Rectangle(i * TileSize, j * TileSize, TileSize, TileSize);
+              tilesList.Add(new Tile(texture, terrain, position));
             }
           }
-          if (terrain != null) {
-            var position = new Rectangle(i * TileSize, j * TileSize, TileSize, TileSize);
-            tilesList.Add(new Tile(texture, terrain.Value, position));
-          }
         }
       }
       tiles = tilesList.ToArray();