Thanks very much for the info, Chad. Would it be possible for you to amend my gist to employ your technique??
Best, Arve On Tue, Sep 16, 2014 at 11:36 PM, Chad Austin <c...@imvu.com> wrote: > If you want to write the C code such that it writes to a float*, then that > data has to live inside the Emscripten heap. > > That is, JavaScript must reserve some space in the Emscripten heap (via > _malloc, for example), and pass the pointer to the C function. > > Then, JavaScript can read the floats out of the array by accessing > HEAPF32[(p>>2) + index] where p is the pointer returned by _malloc and > index is the index into the array. > > > On Tue, Sep 16, 2014 at 2:17 PM, Arve Knudsen <arve.knud...@gmail.com> > wrote: > >> Hi guys >> >> I need to pass an array of floating point numbers from a JavaScript >> library to a C callback, so that the latter can fill the array with data. >> I'm using Runtime.getFuncWrapper to be able to call the C callback from >> JavaScript. >> >> How do I pass an array to the C callback, so that it appears as a >> writeable array of floats to the latter? >> >> I've created a gist of an Emscripten-generated HTML page, to demonstrate >> the scenario: https://gist.github.com/aknuds1/fd6348ab32583dea8b4a. It >> shows what I've tried so far, the problem being that the data written to >> the array by the C function doesn't make it back to the calling JavaScript >> function. Compile the gist into an HTML page like so: >> >> emcc --js-library library.js -o tst.html tst.cpp. >> >> The JavaScript function is called 'initialize', while the C callback is >> called 'callback'. Let me know if anything is unclear. >> >> Thanks, >> Arve >> >> -- >> You received this message because you are subscribed to the Google Groups >> "emscripten-discuss" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to emscripten-discuss+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Chad Austin > Technical Director, IMVU > http://engineering.imvu.com <http://www.imvu.com/members/Chad/> > http://chadaustin.me > > > -- > You received this message because you are subscribed to the Google Groups > "emscripten-discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to emscripten-discuss+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to emscripten-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
