How to create a webgl2 canvas in emscripten

[Brian Gavin]

Hi everyone,

I want to create a webl2 canvas.   I create my canvas doing something similar to emscripten/tests/test_egl.c   I pass the linker flag -s USE_WEBGL2=1 

I create a context setting the attributes like this to create a webgl version 1

EGLint contextAttribs[] =
	{
	EGL_CONTEXT_CLIENT_VERSION, 2,
	EGL_NONE
	};

 I would assume that I would change to this EGL_CONTEXT_CLIENT_VERSION, 3 ?

I would like to create a webgl 1 canvas since some platforms do not support WebGL.

What is the correct way to do this?

Thanks,

Brian Gavin

[Floh]

From glancing over the EGL wrapper code here: https://github.com/kripken/emscripten/blob/master/src/library_egl.js#L270

...it looks to me like there's no support for setting up a WebGL2 context.

You could use the emscripten_webgl_*() functions instead of EGL, these map directly to the HTML5 APIs, for instance here's my code to setup a WebGL2 context, and if this fails fall back to WebGL1:

https://github.com/floooh/oryol/blob/master/code/Modules/Gfx/private/emsc/emscDisplayMgr.cc#L101

(you still need to link with "-s USE_WEBGL2=1")

Cheers,

-Floh.

[Brian Gavin]

Thanks for the information Floh :)

Brian Gavin