passing a program from java to javascript

rafallo

passing a program from java to javascript

in Processing with Other Languages • 1 month ago

Hi

I wrote an entire game in processing (java), and now I want to put it online as a javascript game. If I just select 'javascript mode', it will partially run (meaning the background displays but you cannot actually play), and the firefox console gives me non-relevant error messages.

Is there a standard list of things to do when passing from java to javascript? Or at least a good way to debug it? (Firefox is useless).

My game works perfectly well in Java, but I think i did some ugly programming, such as give the same name to a variable and a function (which is fine in processing), and I did not write at all the words local, static, public, etc... cause I don't know what they're for...

(And I'm not talking about the Android mode...)

Anyway thank you for your help

Replies(6)

GoToLoop

Re: passing a program from java to javascript

1 month ago

There are many pitfalls besides the 1s you've mentioned above.

Main 1 is that Processing.JS is still very much as previous stable 1.5.1.If your program doesn't work in Processing v1.5.1, it won't work in JavaScript mode either!
Don't use non-"Processing sanctioned" Java libraries! Much less 3rd-party libraries!!!
Don't use the same label for variables and functions.
Don't use multiple functions & constructors w/ same label.
Only int and float primitives are initialized w/ zero. The rest is null!
Newer versions of Firefox can't run codes using enhanced for loops w/ Arrays.
Only (int) data-type cast operator removes fractional part of a value.
Sometimes, char data-types need to be explicitly converted to String.
etc...

dimkir

Re: passing a program from java to javascript

1 month ago

And this is your "must read" document as well:

These are instructions to Java Processing developer on understanding what are the limitations of PJS.

http://processingjs.org/articles/p5QuickStart.html

The most frequent problem is variable naming

http://processingjs.org/articles/p5QuickStart.html#variablenamingcare

if you just fix this thing:

ive the same name to a variable and a function

you may get lucky.

ps. Usually if you spent a month writing a game in Java and after decided to run it in processingJS, then you're usually doomed. But you may get lucky. Usual "development flow" is that you always test game in parallel.

You start writing in Java and every time you make some significant modification you run the game in JavaScript mode as well to see if you haven't broken it. Thus testing it in parallel would allow you to be sure that your code is compatible with JS.

rafallo

Re: passing a program from java to javascript

1 month ago

Thank you

I think I'll clean the variable names and then will see. Does the case matter?

GoToLoop

Re: passing a program from java to javascript

1 month ago

Java, JavaScript, C, C++, C#, D, Python, etc are case-sensitive for labels.

rafallo

Re: passing a program from java to javascript

1 month ago

Ok I modified my game, and it runs in Processing 1.5.1 (though ugly), but still not in JS. (I checked the p5quickguide also).

I import the library Triangulate, but GoToLoop said it was a bad idea, how can I use this library in JS?

Also I don't understand the sentence

Newer versions of Firefox can't run codes using enhanced for loops w/ Arrays.

maybe it is an issue. When you say

Don't use multiple functions & constructors w/ same label.

It means that a class cannot have several constructors (with different type of arguments)? (I made experiments on simple examples and it seems to work).

Well, thanks again!

GoToLoop

Re: passing a program from java to javascript

1 month ago

Newer versions of Firefox can't run codes using enhanced for loops w/ Arrays.

If you dunno what an "enhanced" for loop is, chances are high you're not using such loop. Maybe...

And as I've mentioned, that issue is only for newer Firefox versions + when using regular Arrays on that.

It means that a class cannot have several constructors (with different type of arguments)? (I made experiments on simple examples and it seems to work).

I doubt it works in JavaScript mode. Am I wrong?

AFAIK, JavaScript doesn't have a notion of same label functions/constructors w/ different signatures.
As well as variables & functions sharing the same label. Each 1 gotta be unique.

I import the library Triangulate, ...

Import means compiled Java code. They can't be used in JavaScript!
Either you gotta find a corresponding JavaScript library or...
If you have access to a library's source code, you may try to insert it in a separate tab.
And pray that it too can be converted to JavaScript along your code.

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