OXP Development Best Practices

[phkb]

I think this is the best place to put this...

When using timers, the normal, widely-used standard for creating the callback function is like this:

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this.$myFunction = function() {...}

However, internally, Oolite is unable to determine the function name from this definition, so any errors that relate to the timer, for instance

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10:03:18.802 [script.javaScript.unrootedTimer]: ----- WARNING: Timer <OOJSTimer 0x39246230>{nextTime: 30.002, one-shot, running, function: anonymous} 
is being garbage-collected while still running. You must keep a reference to all running timers, or they will stop unpredictably!

are impossible to trace back to the source.

However, simply by defining your callback function like this:

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this.$myFunction = function $myFunction() {...}

the function name can be correctly identified and debugging issues is much easier.

This also goes for instances where the function has been defined in the timer initialisation step:

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var myTimer = new Timer(this, function $myCallback() {...}, 5, 0);

[UK_Eliter]

I have noticed that error messages about timers do not give the timer name. However, I am unsure I understand your rememdy.

My scripts constructions of this form:

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this.dieTimer = new Timer(this,this.$die, 1.7);

What should I replace them with? With constructions of the following form?

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this.dieTimer = new Timer(this,function this.$die, 1.7);

Also, if I make the change you are recommending, do I need to change how I stop timers, remove timers, etc.?

Thanks.

[phkb]

What should I replace them with?

If you have your timer initialised like this:

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this.dieTimer = new Timer(this,this.$die, 1.7);

...then the function you are calling should be declared like this:

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this.$die = function $die() {
	// code of the function follows...
}

Basically, all you're doing is repeating the name of the function between the "function" and the "()".

Nothing else about the timers needs to change. All this does is gives the JS engine a function name to work with when displaying information back to you in the log file.

[UK_Eliter]

Got it. I think. I'll report back if I have problems. Thank you.

[cag]

If you plan on profiling your code, I recommend adding the repeat name on all your functions. Otherwise you get:

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                                                        NAME  T  COUNT    TOTAL     SELF  TOTAL%   SELF%  SELFMAX
                                     WorldScriptsGetProperty  N    779    43.52    39.73    42.9    39.1     0.25
                                        OOStringFromJSString  N   1536     7.63     7.63     7.5     7.5     0.19
                                             ShipGetProperty  N   3778    13.91     7.07    13.7     7.0     0.01
                              (telescope.js:628) <anonymous>  J    244    86.55     5.88    85.3     5.8     0.19
                                         ShipEquipmentStatus  N    755    12.67     5.25    12.5     5.2     0.03
                              (telescope.js:670) <anonymous>  J    142    48.02     5.00    47.3     4.9     0.25
                                           EntityGetProperty  N   3278     7.64     4.76     7.5     4.7     0.02
    -[NSString(OOJavaScriptExtensions) oo:jsValueInContext:]  N   1281     3.99     3.99     3.9     3.9     0.03
                              (telescope.js:767) <anonymous>  J    144     6.31     2.13     6.2     2.1     0.25
                                         JSShipGetShipEntity  N   4533     1.73     1.73     1.7     1.7     0.01
                                         OOJSEntityGetEntity  N   3284     1.62     1.62     1.6     1.6     0.01
                              (telescope.js:609) <anonymous>  J    142    12.58     1.49    12.4     1.5     0.04
                              (telescope.js:621) <anonymous>  J    143    11.32     1.47    11.2     1.4     0.04
                                      JSValueToEquipmentType  N    755     7.02     1.32     6.9     1.3     0.03
                                      

By adding the 2nd function name, all the above "<anonymous>" tags get replaced with the actual function names. Esp. important if you're modifying code in real-time (ie. w/o restarting oolite), as the line numbers quickly become useless.

[UK_Eliter]

I've just discovered error-checking plugins for editors. Specifically, the jshint javascript plugin for Sublime Text (though jshint has plugins for other editors). Getting such 'linters' installed, in Linux and especially Windows, was a pain. Also, I can't seem to stop jshint complaining about "use strict";. Further, it complains about problems that might seem merely cosmetic, such as missing semi-colons at the end of functions. Still, the plugin did pick up some errors of a more substantial kind, though even in nearly all of those cases the errors would not have been such - I hope - to affect functionality.

Anyone else use such a thing? (I've stated using a Bash linter on Linux too.)

[cag]

I'm on Windows and use NotePad++ with a JSLint/JSHint plug-in. I find JSHint more useful, though I think we're stuck w/ the
Use the function form of "use strict"
message. You can DL the plug-in here:

https://sourceforge.net/projects/jslintnpp/

unzip and copy the .dll file into C:\Program Files (x86)\Notepad++\plugins\

In the JSHint options, I've got this:

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addFrameCallback, checkScanner, clock, console, consoleMessage, defaultFont, displayNameForCommodity, EquipmentInfo, 
expandDescription, expandMissionText, formatCredits, formatInteger, galaxyNumber, global, guiScreen, isValidFrameCallback, 
log, manifest, mission, missionVariables, oolite, player, randomInhabitantsDescription,  randomName, removeFrameCallback, 
setScreenBackground, setScreenOverlay, Sound, SoundSource, System, system, takeSnapShot, timeAccelerationFactor, Timer, 
Vector3D,worldScriptNames, worldScripts

in the "Predefined" options box (there may be more oolite specific ones, I just add them as they come up) and this:

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elision:true, shadow:false, esnext: true, validthis: true, curly: false, maxerr: 1000, asi: true, laxbreak: true, undef: true, unused:true

in the "Additional Options" box. Don't ask me what these do (it was a hit or miss procedure). The only message I get once all the errors are fixed is the one about "use strict". I don't think our version of JS (whatever that is) has it and this message can be ignored.

Given how long it takes to rebuild the cache and launch, this can be a real time-saver in the dev cycle. And if you're loading newly edited functions into the debug console, this is a must, as the console cannot give you line numbers for any errors.

[UK_Eliter]

Hi cag,

The web does mention ways of avoiding the 'use strict' nag in JSHint. One of them involves doing something to every function in one's script. That's not worth it. There is at least one other way, though, at least for Sublime Text; but this other method / these other methods looked a bit involved themselves.

I don't see the other errors you mention, except perhaps one to do with SoundSource; I think the correct form of this is indeed SoundSource(), even though Oolite doesn't complain about SoundSource. Also, at one point the 'linter' did report something about some WorldScripts formulation, but that message seemed to go away.

PS: I use NotePad++ (on Windows) but only for Autohotkey coding and only because I can't find a SublimeText plugin for that. There are things I dislike about Sublime, but I do prefer it to NotePad++.

[Svengali]

You don't need to do it for every function. Just wrap your code in a function. Please also note that the jshint and the global settings will vary from script to script - sometimes you don't need them at all.

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/* jshint <your options> */
/* global <your global vars> */
(function(){
"use strict";
<your code>

}).call(this);

[Day]

Anyone else use such a thing?

I use Intellij Idea.

[UK_Eliter]

Svengali: thank you - I thought someone here would know! The procedure is a bit of a pain - if one has many scripts - but now that I've got it set up, it's good.

[another_commander]

Cholmondely's post here reminded me of something that has been quite a bit wrong for some time with regards to nebulae from OXPs. This is an issue found with Cinematic Skies 1.3, but it could affect also other expansions which touch the nebulae in the game.

If you have Cinematic Skies installed from the Expansion Manager and dive in any planet's atmosphere, you will most likely end up looking at something like this when you look up:


This is a heavy immersion breaker. The problem is that Cinematic Skies uses colorful RGB images for its nebulae. This does enhance the vibrance of the nebula colors in the game, but unfortunately the engine does not expect this type of data for nebulae. It requires grayscale images instead, while the colors themselves are managed from within planetinfo.plist by means of nebula_color_1, nebula_color_2, sky_color_1/2 etc. Those interested can check the core game files for reference.

The fix is of course to convert all these images inside the Textures folder to grayscale. For Cinematic Skies I have already done this and you can get a fixed version from this link. With this installed, the exact same location now looks clean and tidy like this:


Remember dear OXP creators, if you are juggling with nebulae, give the engine what the engine expects and you will be rewarded.

[Cody]

That link's asking me to sign-in to download.

[another_commander]

That link's asking me to sign-in to download.

Strange. The file details list its sharing permissions as Everyone with the link can view.

[cbr]

That link's asking me to sign-in to download.

confirmed behaviour.