XNA Spritebatch sorting by texture vs depth

Question

I am refining my 2D game engine, and I want to look in to sorting sprite batches by texture (because I'm quite often using the same textures repeatedly).

However, I also want to retain a few 'layers' of depth (i.e. ground < buildings < units < GUI etc).

My question is, which of the following is the best approach (in terms of performance)?

1. Create multiple SpriteBatches and Begin() and End() them in order; or...
2. Create a single SpriteBatch and call Begin() and End() multiple times, once for each layer (in order)?

Answer 1

There is no reason to have multiple SpriteBatch objects unless you are using them as a "sprite buffer" (a list of sprites to be drawn when End is called) and filling multiple buffers up at the same time.

If you are going in and out of begin/end blocks, you can reuse the SpriteBatch object (there is no saved state between blocks).

There's no major effect on performance. But multiple SpriteBatch objects will use more memory.

As you probably already know, SpriteBatch (in XNA 4.0) only batches sprites together (improving performance) if two or more sprites share the same texture and are drawn sequentially and within the same begin/end block (and if Immediate mode is not set). It sounds like both of your methods will produce the same batches - and thus no performance difference.

Answer 2

You only need multiple SpriteBatches if you like to have other settings for the new layer. So using the same SpriteBatch twice or more is just fine.

You could also consider using only a single batch if everything is the same. Just sort your sprites into buckets and draw them at the right time within the batch.