Add progress parameter for ShineFX

[orcomarcio]

The ShineFX it's cool looking, but without being able to control it it's hard to make it useful.
To try and make a single shine I even tried to add/remove the fx only when i need it, but it seems the progress it's tied to global time or something like that, so when I add it back in it doesn't start form the top.
Unless you want something shining constantly or you don't mind turning it on/off in an abrupt manner, is hard to use.
I'd like to control the progress myself, like shining once or moving the reflex back and forth (basically have a value i can tween as i fit).

[spayton]

yes, this would be useful, for each shine to optionally have its own progress, so you can add it to something and ensure it doesn't start midway