some notes on shadowmap rt format

Texture Atlas

pros:

• very flexible shadowmap layout managment, can combine different size of csm/spotlight/pointlight shadow into one texture
• only 1 binding slot in shadowdepthrendering
• don’t need to switch rt when render different light shadowmaps cons:
• big texture made load/store bindwidth increase
• may have space waste
• need border between different shadow maps

Texture Array

pros:

• load/store bindwidth is same with render single shadowmap cons:
• fixed texture size of each slice, to achieve different size texture, need to create multiple arrays or manage a atlas inside texturearray
• some old hardware don’t support it
• need to switch rt when render different light shadowmaps(for csm, split each cascade rendering into different frames can reduce rt switch)

Bindless Texture

pros:

• arbitrary size texture array cons:
• need modern hardware