Good find, added PR https://github.com/emscripten-core/emscripten/pull/13776 to add the missing function.
pe 5. maalisk. 2021 klo 21.49 'Sam Clegg' via emscripten-discuss ([email protected]) kirjoitti: > > > > On Fri, Mar 5, 2021 at 9:04 AM 'Phil Endecott' via emscripten-discuss > <[email protected]> wrote: >> >> Dear Experts, >> >> Has anyone tried to use OpenGL transform feedback in Emscripten? >> >> In case you are unfamiliar, transform feedback is a way of >> storing the output of a vertex shader into a buffer. This is >> useful for a couple of purposes: you can store updated vertex >> data and feed that back into the vertex shader for the next >> frame (e.g. particle systems), or you can get something like >> a compute shader by disabling rasterisation and reading the >> transform feedback output buffer's data to the CPU. I'm trying >> to do the latter. >> >> I've got something that basically works but I'm unsure how >> best to read the results from the transform feedback output >> buffer. >> >> I believe OpenGL ES has only glMapBufferRange; WebGL2 has only >> getBufferSubData. Emscripten provides glMapBufferRange when >> FULL_ES3 is enabled, but that seems only to be for writing to >> the buffer, not for reading from it. Currently I have a bit >> of EM_JS to wrap getBufferSubData - is this the best solution?: >> >> EM_JS(void, getBufferSubData, (intptr_t addr, size_t length), { >> // must length be scaled, as well as addr? >> GLctx.getBufferSubData(GLctx.TRANSFORM_FEEDBACK_BUFFER, 0, HEAPF32, >> addr >> 2, length); >> }); >> > > I'm not a webgl expert but it looks like something that could/should be added > to library_webgl2.js. > > Maybe could even just be added to the list of pass through functions at the > end? > > cheers, > sam > >> >> Thanks, Phil. >> >> >> >> >> -- >> 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 [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/emscripten-discuss/1614963871702%40dmwebmail.dmwebmail.chezphil.org. > > -- > 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 [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/emscripten-discuss/CAL_va29mMr-g0JHTdtRpgACdztJ7UVkyFrKv6kGG26sitB480Q%40mail.gmail.com. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/emscripten-discuss/CA%2B6sJ-2C-1bTfOtr0v4Oo1-okg5uLcM1HqVSL9EVRHVPfh-g2g%40mail.gmail.com.
