Hi,
now I am really confused. This would mean that my solution should actually
work, doesn't it (when calling *emscripten_resume_main_loop* before
*transferbuffer(cstyle_ptr);*)? However it seems that the
emscripten_pause_main_loop doesn't have any effect at all. It progresses
without pausing and still the call to transferbuffer doesn't get executed,
although there is neither a compilation error nor any error in the Browser
console. Seems, I am even more stuck than I thought...
Am Freitag, 7. Februar 2014 04:53:01 UTC+1 schrieb jj:
>
> Functions wrapped with cwrap and ccall should execute independent of
> whether there is a main loop running or not. Also, it is possible to
> directly write to and read from memory by using the {{{ heapSetValue }}}
> and {{{ heapGetValue }}} mechanisms if you are implementing a --js-library
> file, and from other .js files, by directly accessing the global HEAPU32
> etc. arrays. See the existing src/library_xx.js files with examples of who
> those set and get values are being used, they should cover the most of it.
>
>
> 2014-02-06 Stefan Meier <[email protected] <javascript:>>:
>
>>
>>
>> just had another thought. Is it perhaps possible to write directly to
>> memory? I think the problem with this code:
>>
>> * var cstyle_ptr = allocate(intArrayFromString(userinput), 'i8',
>> ALLOC_NORMAL);*
>> * transferbuffer = Module.cwrap('transferbuffer', 'void',
>> ['string']);*
>> * transferbuffer(cstyle_ptr);*
>>
>> * emscripten_start_main_loop();*
>> is that transferbuffer is not executed because the main loop has stopped,
>> however if I could "inject" the userinput directly into the memory and then
>> resume the main loop, perhaps this could work?
>>
>>
>>
>> Am Donnerstag, 6. Februar 2014 17:56:03 UTC+1 schrieb jj:
>>
>>> One option for blocking keyboard input you could try is to register a
>>> keyboard event callback e.g. via the emscripten library_html5.h handlers,
>>> and having ms_getchar() pause the main loop like you now do, and when you
>>> do get a key press, call resume on the main loop. Alternatively, if you
>>> don't want to keep pausing and resuming the main loop, you could just track
>>> a boolean that avoids the execution of any instructions in your interpreter
>>> while the key event query is pending. Unfortunately real blocking input is
>>> not possible without a dialog box.
>>>
>>> You will need to break up the code that calls ms_getchar() to
>>> immediately return out of the event handler, and have the rest of the
>>> original code after ms_getchar() to be executed only after the keyboard
>>> event is received.
>>>
>>> Jukka
>>>
>>>
>>>
>>>
>>> 2014-02-06 Stefan Meier <[email protected]>:
>>>
>>> Hi,
>>>>
>>>> first of all I want to apologize if this is not the right group for my
>>>> questions, but I didn't find a more appropriate one. Recently I started my
>>>> very first steps with emscripten - which btw is almost too cool to be
>>>> really existing .-)
>>>>
>>>> What I intended to do is porting an interpreter for text adventures
>>>> written in C (called Magnetic, available under GPL). The interpreter is
>>>> written in C und uses only stdio for input and output. There is no SDL
>>>> version and considering the "nature" of the tool, SDL would be a lot
>>>> overhead with gaining nothing, probably.
>>>>
>>>> While I managed to get the emscripten version to do its output to plain
>>>> html after a while I am now completely stuck when trying to get the user
>>>> input working. Before I throw everything into the garbage can, perhaps
>>>> someone with better JS skills than I have (and that's not a major
>>>> challenge), can take a look at the following parts and confirm my current
>>>> assumption: not solvable - or better, give me some hints what can be done.
>>>>
>>>> The main loop of the interpreter is as simple as this:
>>>> *running = 1;*
>>>>
>>>>
>>>> *while (running) running=ms_rungame();*
>>>> The interpreter core is actually some kind of very reduced 68k emulator
>>>> and each call to the ms_rungame "executes" one instruction. Now, when the
>>>> interpreter is running, at some point it runs to a function called
>>>> ms_flush
>>>> for doing the output. I was able to gain from the various samples in the
>>>> emsdk a way to get the output written to plain html with something like
>>>> this:
>>>> *sprintf(outBuffer, "reformatAndSet('%c','textout')",buffer[j]);*
>>>> *emscripten_run_script(outBuffer);*
>>>> in the C code and this in the JS code:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> * function reformatAndSet(text, target) { text =
>>>> text.replace(/&/g, "&"); text = text.replace(/</g, "<");
>>>>
>>>> text = text.replace(/>/g, ">"); text = text.replace('\n',
>>>> '<br>',
>>>> 'g'); document.getElementById(target).innerHTML += text; }*
>>>> Most probably not a nice solution, but at least it works. But then I
>>>> reach my showstopper. So when contuing at some point the interpreter calls
>>>> a function named ms_getchar, which does fill an internal buffer array with
>>>> the user input in a loop of getchar calls and then return the chars after
>>>> after the other in subsequent calls to the ms_getchar routine. In the C
>>>> version this function waits for the user input. Emscripten replaces the
>>>> getchar calls with window.prompt calls, which actually do work, but from
>>>> the point of the user experience are no real option. So, the problem is:
>>>> Is
>>>> it possible to keep the ms_getchar busy or blocked until the user has done
>>>> his input (without locking up the browser). I tried a lot of different
>>>> approaches, but never came close to a solution and as far as I understand
>>>> JS can not be blocked or kept busy with threads, so it seems I am lost
>>>> here?!?.
>>>> My last try was something like this, but this didn't work, either, most
>>>> probably because I got wrong what the emscripten_start_main_loop and
>>>> emscripten_stop_main_loop calls do. I also found a reference to a function
>>>> emcripten_push_Main_loop_blocker, but couldn't find a sample how to
>>>> use it. Another thought was if it might be possible to run the interpreter
>>>> loop in a web worker, but I guess I will run into problems with filling my
>>>> html then?
>>>>
>>>> Last try (partly reconstructed, tried such much with the source that I
>>>> messed it up at some point). Please bear with me if that is pure nonsense,
>>>> I am not very familiar with JS, especially not with the parts beyond
>>>> simple
>>>> web pages.
>>>> in the HTML:
>>>> *<form onsubmit="setInternalBuffer();return false;"><input type="text"
>>>> size="50" maxlength="255" id="textin"></form>*
>>>> and
>>>> *function setInternalBuffer() {*
>>>> * var userinput = document.getElementById('textin').value;*
>>>> * var cstyle_ptr = allocate(intArrayFromString(userinput), 'i8',
>>>> ALLOC_NORMAL);*
>>>> * transferbuffer = Module.cwrap('transferbuffer', 'void',
>>>> ['string']);*
>>>> * transferbuffer(cstyle_ptr);*
>>>> * emscripten_start_main_loop();*
>>>>
>>>> * }*
>>>> in the C code:
>>>> *void transferbuffer(char * input)*
>>>> *{*
>>>> * strcpy(inbuf,input);*
>>>> *}*
>>>> and
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *char ms_getchar() { int c=0; emscripten_pause_main_loop();
>>>> if ((c = inbuf[inpos]) == '\n' || !c) { inpos = 0;
>>>> memset(inbuf,0x00,256); c=0; } return (char)c; }*
>>>>
>>>> I guess, the transferbuffer call in the JS function is not executed
>>>> because the main loop is stopped?!?
>>>>
>>>> Any chance to get this working or is it as simple as this not being
>>>> suitable for JS?
>>>>
>>>> Many, many thanks for listening and your help. If you want to mess
>>>> around with the stuff yourself, please let me know and I'll make it
>>>> available, it's open source anyway.
>>>>
>>>> Stefan Meier
>>>>
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>>>>
>>>
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