finished static sprite batch optimizations

CHANGELOG.md

@@ -19,7 +19,7 @@ Improvements
 - Improved EnumHelper.GetValues signature to return an array
 - Allow using external gesture handling alongside InputHandler through ExternalGestureHandling
 - Discard old data when updating a StaticSpriteBatch
-- Drastically improved StaticSpriteBatch batching performance
+- **Drastically improved StaticSpriteBatch batching performance**
 
 Fixes
 - Fixed TokenizedString handling trailing spaces incorrectly in the last line of non-left aligned text

MLEM/Graphics/StaticSpriteBatch.cs

@@ -43,6 +43,7 @@ namespace MLEM.Graphics {
         private readonly SpriteEffect spriteEffect;
         private readonly List<DynamicVertexBuffer> vertexBuffers = new List<DynamicVertexBuffer>();
         private readonly List<Texture2D> textures = new List<Texture2D>();
+        // TODO this can still be optimized by not giving items with a unique depth a single-entry set immediately
         private readonly SortedDictionary<float, ISet<Item>> items = new SortedDictionary<float, ISet<Item>>();
 
         private IndexBuffer indices;