Pre-compute texture-source Rectangles.

Fixes #14.

GitOrigin-RevId: e09d86a099

Shared/World.cs

@@ -18,63 +18,53 @@ namespace SemiColinGames {
 
   class Tile {
     readonly Texture2D texture;
+    readonly Rectangle textureSource;
 
     public Tile(Texture2D texture, Terrain terrain, Rectangle position) {
       this.texture = texture;
       Terrain = terrain;
       Position = position;
+      this.textureSource = TextureSource();
     }
 
     public Rectangle Position { get; private set; }
     public Terrain Terrain { get; private set; }
 
     public void Draw(SpriteBatch spriteBatch, Camera camera) {
-      int size = World.TileSize;
       Vector2 drawPos = new Vector2(Position.Left - camera.Left, Position.Top);
+      spriteBatch.Draw(texture, drawPos, textureSource, Color.White);
+    }
+
+    private Rectangle TextureSource() {
+      int size = World.TileSize;
       switch (Terrain) {
         case Terrain.Grass: {
-          Rectangle source = new Rectangle(3 * size, 0 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(3 * size, 0 * size, size, size);
+          }
         case Terrain.GrassL: {
-          Rectangle source = new Rectangle(2 * size, 0 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(2 * size, 0 * size, size, size);
+          }
         case Terrain.GrassR: {
-          Rectangle source = new Rectangle(4 * size, 0 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(4 * size, 0 * size, size, size);
+          }
         case Terrain.Rock: {
-          Rectangle source = new Rectangle(3 * size, 1 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(3 * size, 1 * size, size, size);
+          }
         case Terrain.RockL: {
-          Rectangle source = new Rectangle(1 * size, 2 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(1 * size, 2 * size, size, size);
+          }
         case Terrain.RockR: {
-          Rectangle source = new Rectangle(5 * size, 2 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(5 * size, 2 * size, size, size);
+          }
         case Terrain.Water: {
-          Rectangle source = new Rectangle(9 * size, 2 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;
-        }
+            return new Rectangle(9 * size, 2 * size, size, size);
+          }
         case Terrain.Block: {
-          Rectangle source = new Rectangle(6 * size, 3 * size, size, size);
-          spriteBatch.Draw(texture, drawPos, source, Color.White);
-          break;    
-        }
+            return new Rectangle(6 * size, 3 * size, size, size);
+          }
         case Terrain.Empty:
         default:
-          break;
+          return new Rectangle();
       }
     }
   }