particle script helper

[tommo.zhou]

I wrote a particle script helper for MOAI to help write readable particle script.

Source code here:

http://pastebin.com/feWDLXyT



Example here (based on samples/basic/distanceEmitter.lua):

http://pastebin.com/NbhKzXHu



I'd be happy if someone find it useful.

[patrick]

That's awesome!

Would love to ship this with the SDK. Can you add a licensing note at the top, maybe MIT license or something similar? If you do that I'll grab a copy and include it w/ the next release. Will also grab a copy for the wiki.

(Also: would you like a login to be a wiki contributor? Still looking for volunteers...)

[tommo.zhou]

Copyright header added (MIT).

But I found that only the first register can be shared properly across init/render scripts. Maybe it's a bug?

I'd like to contribute to the wiki,  how can I register?

[patrick]

Nice!

Todd will send you a wiki login.

Re the register bug, I haven't looked closely but off the top of my head... when you call reserveParticles the second number is the total number of registers that get allocated for each particle. So if you have a '1' there, then the particle will only remember the contents of the first register from call to call (and between scripts). Try using a bigger number. If that doesn't fix it I will set some time aside to troubleshoot it tomorrow or the next day.

[tommo.zhou]

Ok, that fix the problem. Sorry for not reading doc carefully.

[patrick]

Great!

[mikea]

Tommo - email me at "mike" "at" "ziplinegames" "dot" "com" and I'll get you set up with a wiki account.

[patrick]

Grabbing this now to go into the SDK release. Thanks again for contributing it!

[tommo.zhou]

Wiki page added.

There's a bug in my script. I've fixed it and uploaded to pastebin, please replace it in the release. 

http://pastebin.com/feWDLXyT

:)



*EDIT:

I think it might be handy if there are some basic math functions in particle script, like cos/sin...

[pygy79]

This is very cool :-)



I have a suggestion. Rather than using setfenv, you could pass what is currently the environment as an explicit parameter. 

It makes the DSL slightly heavier, but not much, and you don't have to worry about shadowing the magic variables with upvalues, or to declare upvalues to access otherwise global variables inside the callbacks.

local init=makeParticleScript(function(_)
	_.r1=180-vecAngle(_.p.dx,_.p.dy)   --r1 is a register
end,reg)

local render=makeParticleScript(function(_)
	_.p.x=_.p.x+_.p.dx
	_.p.y=_.p.y+_.p.dy

	_.sprite()
	_.sp.rot=_.r1
	_.sp.sx=_.ease(0.1,3,MOAIEaseType.SHARP_EASE_IN)
	_.sp.opacity=_.ease(1,0,MOAIEaseType.EASE_OUT)
end,reg)

[patrick]

@tommo.zhou Additional trig functions are in our backlog. The code is in moai-dev under samples/contrib - just send me a pull request if/when you want to update it.