Atlas UI in unity
A 2D Project uses Sprites
and other graphics to create the visuals of its Scenes
. This means a single Project might contain many Texture files. Unity normally issues a draw call for each Texture in the Scene; however, in a Project with many Textures, multiple draw calls become resource-intensive and can negatively impact the performance of your Project.
A Sprite Atlas is an Asset that consolidates several Textures into a single combined Texture. Unity can call this single Texture to issue a single draw call instead of multiple draw calls to access the packed Textures all at once at a smaller performance overhead.