Packing Sprites into a Texture Atlas in MonoGame
While building Vulcard for the Game Programming Lab at ETH Zurich, we accumulated dozens of individual sprite PNGs for icons and UI elements. Loading each as a separate texture works fine early on. It’s not how you want to ship, though. Every SpriteBatch.Draw call that switches textures flushes the GPU batch, and 60 sprites can easily mean 60 separate draw calls per frame. The fix is a texture atlas: one large texture containing everything, so the batch stays intact.
We have already been using MLEM which supports spritesheets in the form of its DataTextureAtlas. However, images have to be manually merged into a single file and documented in a .atlas metadata file.
To automate this process I built Vulcard.AtlasPacker, a content pipeline extension that reads a plain-text .atlaspack file and produces a packed texture plus the companion .atlas metadata file at content build time.
This post walks through installation, the manifest format, processor options, and how to load the result at runtime using MLEM’s DataTextureAtlas.