[aquaria] Patch to run Lua scripts as threads
Andrew Church
achurch+aquaria at achurch.org
Tue Jun 29 15:41:20 EDT 2010
That sounds pretty similar to my approach, only using an explicit table
instead of creating a new environment table from the C++ side. But if
we're going to update the scripts anyway, wouldn't it be simpler to just
use Lua's built-in local variable functionality? E.g., instead of
n = 0
function init(me)
n = getNaija()
end
you make the first line "local n = 0", and if my understanding of Lua's
scoping rules is correct, "n" is then local to that specific script. I
think I read that local variables are also faster than globals, though
I can't recall the reference at the moment.
The one potential issue I've seen so far with this is that Lua doesn't
seem to have any facility for loading include files in the current scope,
like "require" in Perl. I haven't looked at all the Lua include files to
see whether it's actually a problem, but if any of them reference global
variables, those would have to be adjusted to take function parameters
instead.
--Andrew Church
achurch at achurch.org
http://achurch.org/
>So, one way to change the scripts to use local variables... Based on what a
>friend told me, and the engine he's working on...
>
>Instead of creating a lua_State for each script, we create a table. Then any
>script can access it's table... something like
>
>v = getVars();
>
>then any local variable just has to have "v." added before it.
>
>This doesn't sound like a super hard change to make, although it would
>involve changing all the scripts.
>
>On Thu, Jun 17, 2010 at 11:05 AM, Andrew Church
><achurch+aquaria at achurch.org<achurch%2Baquaria at achurch.org>
>> wrote:
>
>> I've put together a patch that allows the game's Lua scripts to run as
>> threads within a single Lua state. The patch is admittedly a bit
>> hackish, in that it creates a nested environment for each thread so the
>> global variables defined in each script don't interfere with those used
>> by other scripts, but IMHO the memory savings -- typically around 80% of
>> Lua's current memory usage, for example ~16MB in Home Waters -- make it
>> worth the change. The nested environment hack could of course be
>> removed in the future if the scripts are updated to use local variables.
>> I haven't tested the patch extensively, but in theory it should be safe,
>> as the only effective change is merging the common function set into a
>> single read-only parent environment.
>>
>> The patch is attached below, as a compressed file due to its length.
>> (Ryan, I hope that's not a problem for either you or the mailing list
>> software!) The actual changes aren't too major; the bulk of the patch
>> is due to s/*L/baseState/ in ScriptInterface::createBaseLuaVM()
>> (formerly initLuaVM(), which is now used only for threads).
>>
>> The patch is also in my repository (http://achurch.org/cgi-bin/hg/aquaria/
>> )
>> on branch "single-lua-state". It's actually committed as two patches
>> there, since part of the change is identical to one of my PSP patches,
>> but I've merged them here for (what I hope is) convenience.
>>
>> --Andrew Church
>> achurch at achurch.org
>> http://achurch.org/
>>
>> _______________________________________________
>> aquaria mailing list
>> aquaria at icculus.org
>> http://icculus.org/mailman/listinfo/aquaria
>>
>
>
>
>--
>Alec Holowka
>www.infiniteammo.ca
>www.bit-blot.com
>
>--00c09f99e54989e40c048a24bf46
>Content-Type: text/html; charset=ISO-8859-1
>Content-Transfer-Encoding: quoted-printable
>
>So, one way to change the scripts to use local variables... Based on what a=
> friend told me, and the engine he's working on...<div><br></div><div>I=
>nstead of creating a lua_State for each script, we create a table. Then any=
> script can access it's table... something like</div>
><div><br></div><div>v =3D getVars();</div><div><br></div><div>then any loca=
>l variable just has to have "v." added before it.</div><div><br><=
>/div><div>This doesn't sound like a super hard change to make, although=
> it would involve changing all the scripts.<br>
><br><div class=3D"gmail_quote">On Thu, Jun 17, 2010 at 11:05 AM, Andrew Chu=
>rch <span dir=3D"ltr"><<a href=3D"mailto:achurch%2Baquaria at achurch.org">=
>achurch+aquaria at achurch.org</a>></span> wrote:<br><blockquote class=3D"g=
>mail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-l=
>eft:1ex;">
>I've put together a patch that allows the game's Lua scripts to run=
> as<br>
>threads within a single Lua state. =A0The patch is admittedly a bit<br>
>hackish, in that it creates a nested environment for each thread so the<br>
>global variables defined in each script don't interfere with those used=
><br>
>by other scripts, but IMHO the memory savings -- typically around 80% of<br=
>>
>Lua's current memory usage, for example ~16MB in Home Waters -- make it=
><br>
>worth the change. =A0The nested environment hack could of course be<br>
>removed in the future if the scripts are updated to use local variables.<br=
>>
>I haven't tested the patch extensively, but in theory it should be safe=
>,<br>
>as the only effective change is merging the common function set into a<br>
>single read-only parent environment.<br>
><br>
>The patch is attached below, as a compressed file due to its length.<br>
>(Ryan, I hope that's not a problem for either you or the mailing list<b=
>r>
>software!) =A0The actual changes aren't too major; the bulk of the patc=
>h<br>
>is due to s/*L/baseState/ in ScriptInterface::createBaseLuaVM()<br>
>(formerly initLuaVM(), which is now used only for threads).<br>
><br>
>The patch is also in my repository (<a href=3D"http://achurch.org/cgi-bin/h=
>g/aquaria/" target=3D"_blank">http://achurch.org/cgi-bin/hg/aquaria/</a>)<b=
>r>
>on branch "single-lua-state". =A0It's actually committed as t=
>wo patches<br>
>there, since part of the change is identical to one of my PSP patches,<br>
>but I've merged them here for (what I hope is) convenience.<br>
><br>
> =A0--Andrew Church<br>
> =A0 =A0<a href=3D"mailto:achurch at achurch.org">achurch at achurch.org</a><br>
> =A0 =A0<a href=3D"http://achurch.org/" target=3D"_blank">http://achurch.or=
>g/</a><br>
><br>
>_______________________________________________<br>
>aquaria mailing list<br>
><a href=3D"mailto:aquaria at icculus.org">aquaria at icculus.org</a><br>
><a href=3D"http://icculus.org/mailman/listinfo/aquaria" target=3D"_blank">h=
>ttp://icculus.org/mailman/listinfo/aquaria</a><br>
></blockquote></div><br><br clear=3D"all"><br>-- <br>Alec Holowka<br><a href=
>=3D"http://www.infiniteammo.ca">www.infiniteammo.ca</a><br><a href=3D"http:=
>//www.bit-blot.com">www.bit-blot.com</a><br>
></div>
>
>--00c09f99e54989e40c048a24bf46--
>
>--===============4162574011203577186==
>Content-Type: text/plain; charset="us-ascii"
>MIME-Version: 1.0
>Content-Transfer-Encoding: 7bit
>Content-Disposition: inline
>
>_______________________________________________
>aquaria mailing list
>aquaria at icculus.org
>http://icculus.org/mailman/listinfo/aquaria
>
>--===============4162574011203577186==--
More information about the aquaria
mailing list