XXL uses Renderware Graphics, which was made at a time where consoles didn't support shader (PS2 and GC use a fixed rendering pipeline if I'm not wrong, they don't support shaders).
The alpha that XXL uses is in the alpha channel
No special textures for that
then what technic they used to achieve particle system effects
i mean its just png images
In the PC version, Renderware might use shader if the GPU supports it, but the shaders used are usually simple.
Most of the effects are billboards with a texture on it
i guess they might be modified stuff for PC version
and PC release was on 2004
PS2 release is the first, on 21.11.03
Then came GC and PC 18.06.04