yes I know that, and sure I know my code isn't optimised yet xD
but I really not sure if this kind of modification can do big performance problem...
The idea is not swaping the texture, the true is, my code isn't very different from the original particle, the difference is, now you can set a sprite sheet and when I create the particle I set the texture frame on it... sure I'll not use it in something with a lot of particle, but for small one shot particles like debris, sparks it can work very nice...