This could be the same bug that popped up on the WebGL dev group here: https://groups.google.com/forum/#!topic/webgl-dev-list/0Omhxnp3_CE, which points to a bug in ANGLE when instanced_arrays is used together with vertex array objects.
It doesn't look like a trivial bug though (back when I still used VAOs I didn't have trouble with the instanced_array extension in simple demos). Cheers, -Floh. Am Sonntag, 4. Oktober 2015 15:29:50 UTC+2 schrieb Wladimir Kröker: > > Hey, > I've been playing around with emscripten and tried instancing but ran into > a problem in windows browsers: > I'm rendering 1 blue square with glDrawArrays() and 6 yellow squares with > glDrawArraysInstanced(). Unfortunately the result > isn't quite what I expect it to be. At least in Windows browsers: > > Expected: > > <https://lh3.googleusercontent.com/-QS9y7wRn-1g/VhEaqyVtijI/AAAAAAAAAGw/hGVh2mGYX3w/s1600/Expected.png> > > Result in Windows browsers (Firefox, Chrome, Opera): > > > <https://lh3.googleusercontent.com/-V7kosdauX1I/VhEayeK2V2I/AAAAAAAAAG4/AKt20p8pi84/s1600/Result.png> > > > I get the expected result if I start the program as an "exe" on Windows or > on Linux (executable on the OS and in browsers). > I tested it with the 1.34.1 emsdk and the portable version on linux. > > Note: It doesn't matter on which OS I create the .html. It just won't show > me the expected result in the mentioned windows browsers. > > The test code can be found here: > https://github.com/compix/Emscripten-Instancing-Test > I tried to keep it as minimal and readable as possible with a few error > checks. > > The cause of the problem seems to be the glVertexAttribDivisor(0, 1) in > InstancingTest.cpp line 156. I didn't have any problems without it. > > I am using 2 attributes for the instancing case: "in_sPos" as the > instanced attribute with divisor 1 and "in_pos" as a non-instanced > attribute. > If I change the order of the attributes in the test code I get the > expected result. But this doesn't really fix the problem because > 1. The order shouldn't matter. > 2. It will cause problems if more geometry and different vertex layouts > come in. > > Maybe there is a problem in my code but I checked it multiple times and I > don't think it's a coincidence that it just doesn't display the expected > result in windows browsers. > > I'd much appreciate if someone could take a look at it. > > Regards > Wladimir > > > -- 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]. For more options, visit https://groups.google.com/d/optout.
