Managing the performance of your game with multiple atlases and parts in Unity depends on several factors, including the total memory usage, the number of draw calls, and how you manage the loading and unloading of these assets. Having separate atlases for Hair, Body, Hands, Feet, Eyes, Mouth, Ear, Nose, Weapon, Backpack, FacialHair, Masks, and other parts is common in games that feature high levels of customization. The key is to optimize how these assets are used and loaded during the game.
For Unity, using multiple atlases can be efficient if managed correctly. Unity's ability to batch draw calls means that having multiple atlases won't inherently cause performance issues, as long as the number of draw calls is kept reasonable. The Spine-Unity runtime also provides tools for dynamically repacking textures at runtime to reduce draw calls, which can be beneficial for games with many customizable parts.
Regarding the parts themselves, having many separate pieces for customization is a common approach. The performance impact will depend on how these parts are managed, the complexity of each part, and the overall number of vertices and bones being animated. Unity and Spine are both capable of handling a significant number of parts and atlases, but optimization techniques such as atlasing, mesh and bone reduction, and efficient asset loading and unloading should be considered to maintain performance, especially on lower-end devices.
The fact that the images are not trimmed and retain their original bounding boxes can increase the memory footprint of your atlases. While this approach facilitates swapping parts with different sizes, it may lead to less efficient use of texture space and potentially higher memory usage. Consider using polygonal packing in Spine to reduce atlas size or dynamically loading only the necessary textures for the current scene or character configuration to optimize performance.
In summary, while having multiple atlases and parts is common in customizable character systems and does not inherently lead to performance issues, careful management and optimization of these assets are crucial to ensure good performance across all devices.
