Improve RuntimeTexturePacker performance by checking against packed textures in the same order as packing

CHANGELOG.md

@@ -58,6 +58,7 @@ Improvements
 - Premultiply textures when using RawContentManager
 - Allow enumerating all region names of a DataTextureAtlas
 - Cache RuntimeTexturePacker texture data while packing to improve performance
+- Improve RuntimeTexturePacker performance by checking against packed textures in the same order as packing
 
 Fixes
 - Fixed SoundEffectReader incorrectly claiming it could read ogg and mp3 files

MLEM.Data/RuntimeTexturePacker.cs

@@ -152,9 +152,12 @@ namespace MLEM.Data {
             if (this.PackedTexture != null)
                 throw new InvalidOperationException("Cannot pack a texture packer that is already packed");
 
+            // we pack larger textures first, so that smaller textures can fit in the gaps that larger ones leave
+            this.textures.Sort((r1, r2) => (r2.Texture.Width * r2.Texture.Height).CompareTo(r1.Texture.Width * r1.Texture.Height));
+
             // set pack areas for each request
             var stopwatch = Stopwatch.StartNew();
-            foreach (var request in this.textures.OrderByDescending(t => t.Texture.Width * t.Texture.Height))
+            foreach (var request in this.textures)
                 request.PackedArea = this.FindFreeArea(request);
             stopwatch.Stop();
             this.LastCalculationTime = stopwatch.Elapsed;