Implement ChangeModel CPE extension, fix potential crash.

ClassicalSharp.csproj

@@ -117,6 +117,7 @@
     <Compile Include="Model\ChickenModel.cs" />
     <Compile Include="Model\CreeperModel.cs" />
     <Compile Include="Model\IModel.cs" />
+    <Compile Include="Model\ModelCache.cs" />
     <Compile Include="Model\ModelPart.cs" />
     <Compile Include="Model\PigModel.cs" />
     <Compile Include="Model\PlayerModel.cs" />

Entities/Player.cs

@@ -1,5 +1,6 @@
 using System;
 using OpenTK;
+using ClassicalSharp.Model;
 using ClassicalSharp.Renderers;
 
 namespace ClassicalSharp {
@@ -27,7 +28,8 @@ namespace ClassicalSharp {
 		public Game Window;
 		public byte ID;
 		public string DisplayName, SkinName;
-		public string ModelName = "humanoid";
+		public string ModelName;
+		public IModel Model;
 		protected PlayerRenderer renderer;
 		public SkinType SkinType;
 		
@@ -35,6 +37,7 @@ namespace ClassicalSharp {
 			ID = id;
 			Window = window;
 			SkinType = Window.DefaultPlayerSkinType;
+			SetModel( "humanoid" );
 		}
 		
 		/// <summary> Gets the block just underneath the player's feet position. </summary>
@@ -94,5 +97,10 @@ namespace ClassicalSharp {
 			rightArmXRot += idleXRot;
 			leftArmXRot -= idleXRot;
 		}
+		
+		public void SetModel( string modelName ) {
+			ModelName = modelName;
+			Model = Window.ModelCache.GetModel( ModelName );
+		}
 	}
 }

Game/Game.cs

@@ -45,7 +45,7 @@ namespace ClassicalSharp {
 		public ParticleManager ParticleManager;
 		public PickingRenderer Picking;
 		public PickedPos SelectedPos;
-		public IModel ModelCache;
+		public ModelCache ModelCache;
 		internal string skinServer, chatInInputBuffer;
 		public bool CanUseThirdPersonCamera = true;
 		FpsScreen fpsScreen;
@@ -143,7 +143,7 @@ namespace ClassicalSharp {
 		
 		protected override void OnLoad( EventArgs e ) {
 			Graphics = new OpenGLApi();
-			ModelCache = new PlayerModel( this );
+			ModelCache = new ModelCache( this );
 			AsyncDownloader = new AsyncDownloader( skinServer );
 			PrintGraphicsInfo();
 			Bitmap terrainBmp = new Bitmap( "terrain.png" );

Model/ModelCache.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+
+namespace ClassicalSharp.Model {
+
+	public class ModelCache {
+		
+		Game window;
+		public ModelCache( Game window ) {
+			this.window = window;
+			cache["humanoid"] = new PlayerModel( window );
+		}
+		
+		Dictionary<string, IModel> cache = new Dictionary<string, IModel>();
+		public IModel GetModel( string modelName ) {
+			IModel model;
+			byte blockId;
+			if( Byte.TryParse( modelName, out blockId ) ) {
+				if( !cache.TryGetValue( "block", out model ) ) {
+					model = new BlockModel( window );
+					cache["block"] = model;
+				}			
+				return model;
+			} else {
+				if( !cache.TryGetValue( modelName, out model ) ) {
+					model = InitModel( modelName );
+					if( model != null ) {
+						cache[modelName] = model;
+					} else {
+						model = cache["humanoid"]; // fallback to default
+					}
+				}
+				return model;
+			}			
+		}
+		
+		IModel InitModel( string modelName ) {
+			if( modelName == "chicken" ) {
+				return new ChickenModel( window );
+			} else if( modelName == "creeper" ) {
+				return new CreeperModel( window );
+			} else if( modelName == "pig" ) {
+				return new PigModel( window );
+			} else if( modelName == "skeleton" ) {
+				return new SkeletonModel( window );
+			} else if( modelName == "zombie" ) {
+				return new ZombieModel( window );
+			}
+			return null;
+		}
+		
+		public void Dispose() {
+			foreach( var entry in cache ) {
+				entry.Value.Dispose();
+			}
+		}
+	}
+}

Network/NetworkProcessor.cs

@@ -147,12 +147,11 @@ namespace ClassicalSharp {
 		// === CPE support list ===
 		// TextHotKey       : unlikely
 		// ExtPlayerList    : yes (only version 1, not 2)
-		// ChangeModel      : planned
 		// EnvWeatherType   : unlikely
 		static string[] clientExtensions = new string[] {
 			"EmoteFix", "ClickDistance", "HeldBlock", "BlockPermissions",
 			"SelectionCuboid", "MessageTypes", "CustomBlocks", "EnvColors",
-			"HackControl", "EnvMapAppearance", "ExtPlayerList",
+			"HackControl", "EnvMapAppearance", "ExtPlayerList", "ChangeModel",
 		};
 		
 		
@@ -635,6 +634,16 @@ namespace ClassicalSharp {
 						Window.RaiseBlockPermissionsChanged();
 					} break;
 					
+				case PacketId.CpeChangeModel:
+					{
+						byte playerId = reader.ReadUInt8();
+						string modelName = reader.ReadString().ToLowerInvariant();
+						Player player = playerId == 0xFF ? Window.LocalPlayer : Window.NetPlayers[playerId];
+						if( player != null ) {
+							player.SetModel( modelName );
+						}
+					} break;
+					
 				case PacketId.CpeEnvSetMapApperance:
 					{
 						string url = reader.ReadString();
@@ -715,10 +724,9 @@ namespace ClassicalSharp {
 		}
 		
 		void UpdateLocation( byte playerId, LocationUpdate update, bool interpolate ) {
-			if( playerId == 0xFF ) {
-				Window.LocalPlayer.SetLocation( update, interpolate );
-			} else {
-				Window.NetPlayers[playerId].SetLocation( update, interpolate );
+			Player player = playerId == 0xFF ? Window.LocalPlayer : Window.NetPlayers[playerId];
+			if( player != null ) {
+				player.SetLocation( update, interpolate );
 			}
 		}
 		#endregion

Rendering/PlayerRenderer.cs

@@ -37,14 +37,14 @@ namespace ClassicalSharp.Renderers {
 		
 		public void Render( double deltaTime ) {
 			pos = Player.Position;
-			Window.ModelCache.RenderModel( Player, this );
+			Player.Model.RenderModel( Player, this );
 			DrawName();
 		}
 		
 		const float nameScale = 50f;
 		private void DrawName() {
 			Graphics.PushMatrix();
-			Graphics.Translate( pos.X, pos.Y + Window.ModelCache.NameYOffset, pos.Z );
+			Graphics.Translate( pos.X, pos.Y + Player.Model.NameYOffset, pos.Z );
 			// Do this to always have names facing the player
 			float yaw = Window.LocalPlayer.YawDegrees;
 			Graphics.RotateY( 0f - yaw );