World: load levels by parsing a JSON level description.

Shared/FpsCounter.cs

@@ -2,8 +2,8 @@ using System;
 
 namespace SemiColinGames {
   class FpsCounter {
+    private readonly int[] frameTimes = new int[60];
     private double fps = 0;
-    private int[] frameTimes = new int[60];
     private int idx = 0;
 
     public int Fps {

Shared/Geometry.cs

@@ -83,15 +83,15 @@ namespace SemiColinGames {
   public readonly struct AABB {
     public readonly Vector2 Position;  // centroid
     public readonly Vector2 HalfSize;
-    public readonly Terrain Terrain;
+    public readonly Tile Tile;
 
-    public AABB(Vector2 position, Vector2 halfSize) : this(position, halfSize, Terrain.Empty) {
+    public AABB(Vector2 position, Vector2 halfSize) : this(position, halfSize, null) {
     }
 
-    public AABB(Vector2 position, Vector2 halfSize, Terrain terrain) {
+    public AABB(Vector2 position, Vector2 halfSize, Tile tile) {
       Position = position;
       HalfSize = halfSize;
-      Terrain = terrain;
+      Tile = tile;
     }
 
     public float Top {

Shared/NPC.cs

@@ -52,15 +52,16 @@ namespace SemiColinGames {
 
     private FSM<NPC> fsm;
 
-    public NPC(Point position) {
+    public NPC(Point position, int facing) {
       Position = position;
+      Facing = facing;
       fsm = new FSM<NPC>(new Dictionary<string, IState<NPC>> {
         { "idle", new IdleState() },
         { "run", new RunState() }
       }, "run");
     }
 
-    public int Facing = 1;
+    public int Facing;
     public Point Position;
 
     public void Update(float modelTime, World world) {

Shared/Player.cs

@@ -22,7 +22,7 @@ namespace SemiColinGames {
 
     // Position is tracked at the Player's center. The Player's bounding box is a rectangle
     // centered at that point and extending out by halfSize.X and halfSize.Y.
-    private Point position = new Point(64, 16 * 12);
+    private Point position;
     private Vector2 halfSize = new Vector2(11, 24);
     private Vector2 eyeOffsetStanding = new Vector2(7, -14);
     private Vector2 eyeOffsetWalking = new Vector2(15, -7);
@@ -36,7 +36,9 @@ namespace SemiColinGames {
     private double jumpTime = 0;
     private float invincibilityTime = 0;
 
-    public Player() {
+    public Player(Point position, int facing) {
+      this.position = position;
+      Facing = facing;
       Health = MaxHealth;
     }
 
@@ -44,7 +46,7 @@ namespace SemiColinGames {
 
     public int Health { get; private set; }
 
-    public int Facing { get; private set; } = 1;
+    public int Facing { get; private set; }
 
     public Point Position { get { return position; } }
 
@@ -92,7 +94,7 @@ namespace SemiColinGames {
             if (box.Intersect(player) != null) {
               Debug.AddRect(box, Color.Cyan);
               reject = true;
-              if (box.Terrain.IsHarmful) {
+              if (box.Tile?.IsHarmful ?? false) {
                 Debug.AddRect(box, Color.Red);
                 harmedByCollision = true;
               }
@@ -110,7 +112,7 @@ namespace SemiColinGames {
             if (box.Intersect(player) != null) {
               Debug.AddRect(box, Color.Cyan);
               reject = true;
-              if (box.Terrain.IsHarmful) {
+              if (box.Tile?.IsHarmful ?? false) {
                 Debug.AddRect(box, Color.Red);
                 harmedByCollision = true;
               }
@@ -128,7 +130,7 @@ namespace SemiColinGames {
         if (groundIntersect.Intersect(box) != null) {
           Debug.AddRect(box, Color.Cyan);
           standingOnGround = true;
-          if (box.Terrain.IsHarmful) {
+          if (box.Tile?.IsHarmful ?? false) {
             Debug.AddRect(box, Color.Red);
             harmedByCollision = true;
           }

Shared/SneakGame.cs

@@ -70,7 +70,7 @@ namespace SemiColinGames {
     private void LoadLevel() {
       camera = new Camera();
       levelIdx++;
-      world = new World(Levels.ALL_LEVELS[levelIdx % Levels.ALL_LEVELS.Length]);
+      world = new World(Content.LoadString("levels/demo.json"));
       scene?.Dispose();
       scene = new Scene(GraphicsDevice, camera);
 

Shared/World.cs

@@ -1,173 +1,123 @@
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
+using Newtonsoft.Json.Linq;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 
 namespace SemiColinGames {
 
-  public class Terrain {
+  public class Tile {
+    private TextureRef texture;
+    private Rectangle textureSource;
 
-    public static Terrain FromSymbol(char symbol) {
+    public Tile(TextureRef texture, Rectangle textureSource, Rectangle position) {
-      if (mapping.ContainsKey(symbol)) {
-        return mapping[symbol];
-      } else {
-        return null;
-      }
-    }
-
-    private readonly static Dictionary<char, Terrain> mapping = new Dictionary<char, Terrain>();
-
-    public static Terrain Empty =
-        new Terrain('\0', Textures.Grassland, 0, 0);
-    public static Terrain Spike =
-        new Terrain('^', Textures.Grassland, 11, 8, isObstacle: true, isHarmful: true);
-    public static Terrain Grass =
-        new Terrain('=', Textures.Grassland, 3, 0, isObstacle: true);
-    public static Terrain GrassL =
-        new Terrain('<', Textures.Grassland, 2, 0, isObstacle: true);
-    public static Terrain GrassR =
-        new Terrain('>', Textures.Grassland, 4, 0, isObstacle: true);
-    public static Terrain Rock =
-        new Terrain('.', Textures.Grassland, 3, 1, isObstacle: true);
-    public static Terrain RockL =
-        new Terrain('[', Textures.Grassland, 1, 2, isObstacle: true);
-    public static Terrain RockR =
-        new Terrain(']', Textures.Grassland, 5, 2, isObstacle: true);
-    public static Terrain Block =
-        new Terrain('X', Textures.Grassland, 23, 0, isObstacle: true);
-    public static Terrain Wood =
-        new Terrain('_', Textures.Grassland, 10, 3, isObstacle: true);
-    public static Terrain WoodL =
-        new Terrain('(', Textures.Grassland, 9, 3, isObstacle: true);
-    public static Terrain WoodR =
-        new Terrain(')', Textures.Grassland, 12, 3, isObstacle: true);
-    public static Terrain WoodVert =
-        new Terrain('|', Textures.Grassland, 9, 5);
-    public static Terrain WoodVertL =
-        new Terrain('/', Textures.Grassland, 9, 4);
-    public static Terrain WoodVertR =
-        new Terrain('\\', Textures.Grassland, 12, 4);
-    public static Terrain WoodBottom =
-        new Terrain('v', Textures.Grassland, 10, 5);
-    public static Terrain WaterL =
-        new Terrain('~', Textures.Grassland, 9, 2);
-    public static Terrain WaterR =
-        new Terrain('`', Textures.Grassland, 10, 2);
-    public static Terrain FenceL =
-        new Terrain('d', Textures.Grassland, 5, 4);
-    public static Terrain Fence =
-        new Terrain('f', Textures.Grassland, 6, 4);
-    public static Terrain FencePost =
-        new Terrain('x', Textures.Grassland, 7, 4);
-    public static Terrain FenceR =
-        new Terrain('b', Textures.Grassland, 8, 4);
-    public static Terrain VineTop =
-        new Terrain('{', Textures.Grassland, 20, 0);
-    public static Terrain VineMid =
-        new Terrain(';', Textures.Grassland, 20, 1);
-    public static Terrain VineBottom =
-        new Terrain('}', Textures.Grassland, 20, 2);
-    public static Terrain GrassTall =
-        new Terrain('q', Textures.Grassland, 13, 0);
-    public static Terrain GrassShort =
-        new Terrain('w', Textures.Grassland, 14, 0);
-    public static Terrain Shoots =
-        new Terrain('e', Textures.Grassland, 15, 0);
-    public static Terrain Bush =
-        new Terrain('r', Textures.Grassland, 13, 2);
-    public static Terrain Mushroom =
-        new Terrain('t', Textures.Grassland, 17, 2);
-
-    public bool IsObstacle { get; private set; }
-    public bool IsHarmful { get; private set; }
-    public TextureRef Texture { get; private set; }
-    public Rectangle TextureSource { get; private set; }
-
-    private Terrain(
-        char symbol, TextureRef texture, int x, int y,
-        bool isObstacle = false, bool isHarmful = false) {
-      if (mapping.ContainsKey(symbol)) {
-        throw new ArgumentException("already have a terrain with symbol " + symbol);
-      }
-      mapping[symbol] = this;
-      IsObstacle = isObstacle;
-      IsHarmful = isHarmful;
-      Texture = texture;
-      int size = World.TileSize;
-      TextureSource = new Rectangle(x * size, y * size, size, size);
-    }
-  }
-
-  class Tile {
-    public Tile(Terrain terrain, Rectangle position) {
-      Terrain = terrain;
       Position = position;
+      this.texture = texture;
+      this.textureSource = textureSource;
     }
 
     public Rectangle Position { get; private set; }
-    public Terrain Terrain { get; private set; }
+    public bool IsHarmful = false;
 
     public void Draw(SpriteBatch spriteBatch) {
       spriteBatch.Draw(
-          Terrain.Texture.Get, Position.Location.ToVector2(), Terrain.TextureSource, Color.White);
+          texture.Get, Position.Location.ToVector2(), textureSource, Color.White);
     }
   }
 
   public class World {
 
+    // Size of World in terms of tile grid.
+    private int gridWidth;
+    private int gridHeight;
+
+    // TODO: remove this.
     public const int TileSize = 16;
     readonly Tile[] tiles;
     readonly Tile[] decorations;
-    readonly NPC[] npcs = new NPC[4];
+    // Kept around for resetting the world's entities after player death or level restart.
-
+    readonly JToken entitiesLayer;
-    // Size of World in terms of tile grid.
-    private readonly int tileWidth;
-    private readonly int tileHeight;
 
+    NPC[] npcs;
     public Player Player { get; private set; }
 
     // Size of World in pixels.
     public int Width {
-      get { return tileWidth * TileSize; }
+      get { return gridWidth * TileSize; }
     }
 
     public int Height {
-      get { return tileHeight * TileSize; }
+      get { return gridHeight * TileSize; }
     }
 
-    public World(string levelSpecification) {
+    private List<Tile> ParseLayer(JToken layer) {
-      Player = new Player();
+      var tileList = new List<Tile>();
-      npcs[0] = new NPC(new Point(16 * 8, 16 * 6));
-      npcs[1] = new NPC(new Point(16 * 28, 16 * 6));
-      npcs[2] = new NPC(new Point(16 * 36, 16 * 6));
-      npcs[3] = new NPC(new Point(16 * 36, 16 * 12));
 
-      var tilesList = new List<Tile>();
+      int layerWidth = layer.SelectToken("gridCellsX").Value<int>();
-      var decorationsList = new List<Tile>();
+      int layerHeight = layer.SelectToken("gridCellsY").Value<int>();
-      string[] worldDesc = levelSpecification.Substring(1).Split('\n');
+      gridWidth = Math.Max(gridWidth, layerWidth);
-      tileWidth = worldDesc.AsQueryable().Max(a => a.Length);
+      gridHeight = Math.Max(gridHeight, layerHeight);
-      tileHeight = worldDesc.Length;
+
-      Debug.WriteLine("world size: {0}x{1}", tileWidth, tileHeight);
+      int dataIndex = -1;
-      for (int i = 0; i < tileWidth; i++) {
+      int tileWidth = layer.SelectToken("gridCellWidth").Value<int>();
-        for (int j = 0; j < tileHeight; j++) {
+      int tileHeight = layer.SelectToken("gridCellHeight").Value<int>();
-          if (i < worldDesc[j].Length) {
+      int textureWidth = Textures.Grassland.Get.Width / tileWidth;
-            char key = worldDesc[j][i];
+      foreach (int textureIndex in layer.SelectToken("data").Values<int>()) {
-            Terrain terrain = Terrain.FromSymbol(key);
+        dataIndex++;
-            if (terrain != null) {
+        if (textureIndex == -1) {
-              var position = new Rectangle(i * TileSize, j * TileSize, TileSize, TileSize);
+          continue;
-              Tile tile = new Tile(terrain, position);
+        }
-              if (tile.Terrain.IsObstacle) {
+        int i = dataIndex % layerWidth;
-                tilesList.Add(tile);
+        int j = dataIndex / layerWidth;
-              } else {
+        Rectangle position = new Rectangle(
-                decorationsList.Add(tile);
+            i * tileWidth, j * tileHeight, tileWidth, tileHeight);
-              }
+        int x = textureIndex % textureWidth;
-            }
+        int y = textureIndex / textureWidth;
-          }
+        Rectangle textureSource = new Rectangle(
+            x * tileWidth, y * tileHeight, tileWidth, tileHeight);
+        tileList.Add(new Tile(Textures.Grassland, textureSource, position));
+      }
+
+      return tileList;
+    }
+
+    private (Player, NPC[]) ParseEntities(JToken layer) {
+      Player player = null;
+      List<NPC> npcs = new List<NPC>();
+      foreach (JToken entity in layer.SelectToken("entities").Children()) {
+        string name = entity.SelectToken("name").Value<string>();
+        int x = entity.SelectToken("x").Value<int>();
+        int y = entity.SelectToken("y").Value<int>();
+        int facing = entity.SelectToken("flippedX").Value<bool>() ? -1 : 1;
+        if (name == "player") {
+          player = new Player(new Point(x, y), facing);
+        } else if (name == "executioner") {
+          npcs.Add(new NPC(new Point(x, y), facing));
         }
       }
-      tiles = tilesList.ToArray();
+      return (player, npcs.ToArray());
-      decorations = decorationsList.ToArray();
+    }
+
+    public World(string json) {
+      JObject root = JObject.Parse(json);
+
+      foreach (JToken layer in root.SelectToken("layers").Children()) {
+        string layerName = layer.SelectToken("name").Value<string>();
+        if (layerName == "entities") {
+          entitiesLayer = layer;
+          (Player, npcs) = ParseEntities(layer);
+          continue;
+        }
+        List<Tile> tileList = ParseLayer(layer);
+        // TODO: add background layer
+        if (layerName == "obstacles") {
+          tiles = tileList.ToArray();
+        } else if (layerName == "decorations") {
+          decorations = tileList.ToArray();
+        }
+      }
+      Debug.WriteLine("world size: {0}x{1}", gridWidth, gridHeight);
 
       // Because we added tiles from left to right, the CollisionTargets are sorted by x-position.
       // We maintain this invariant so that it's possible to efficiently find CollisionTargets that
@@ -182,7 +132,7 @@ namespace SemiColinGames {
       for (int i = 0; i < tiles.Length; i++) {
         Vector2 center = new Vector2(
           tiles[i].Position.Left + halfSize.X, tiles[i].Position.Top + halfSize.Y);
-        CollisionTargets[i + 1] = new AABB(center, halfSize, tiles[i].Terrain);
+        CollisionTargets[i + 1] = new AABB(center, halfSize, tiles[i]);
       }
 
       // Add a final synthetic collisionTarget on the right side of the world.
@@ -201,7 +151,7 @@ namespace SemiColinGames {
     }
 
     void Reset() {
-      Player = new Player();
+      (Player, npcs) = ParseEntities(entitiesLayer);
     }
 
     public void DrawBackground(SpriteBatch spriteBatch) {