Bug 216010 – [WebGL2] Support EXT_color_buffer_half_float on WebGL 2.0 contexts

• Component: WebGL
• Status: RESOLVED FIXED

[Kenneth Russell]

Per agreement in the WebGL working group, the EXT_color_buffer_half_float extension is being revised to be supported on WebGL 2.0 contexts:
https://github.com/KhronosGroup/WebGL/pull/3146

The reason for this change is principally that iOS devices support 16-bit floating-point render targets but not 32-bit, so the WebGL 2.0 EXT_color_buffer_float extension, which covers both, can not be supported there.

Developers are noticing this functionality gap:
https://github.com/playcanvas/engine/pull/2123#issuecomment-682438222

WebKit's WebGL 2.0 implementation should be updated as soon as possible to track this change so that developers upgrading to WebGL 2.0 can continue to use floating-point render targets on iOS.

[Kenneth Russell]

The update to the extension specification has landed, so implementation of this can proceed. Thanks James for taking this!

[James Darpinian]

Created attachment 407639 [details]
Patch

[James Darpinian]

Working on a test in https://github.com/KhronosGroup/WebGL/pull/3147, will add to this patch tomorrow.

[EWS Watchlist]

Note that there are important steps to take when updating ANGLE. See http://trac.webkit.org/wiki/UpdatingANGLE

[Kenneth Russell]

Looks like webgl/2.0.0/conformance2/extensions/promoted-extensions.html needs to be updated here and upstream as well. Could you please put up another pull request on KhronosGroup/WebGL for that? Thanks!

[Kenneth Russell]

Comment on attachment 407639 [details]
Patch

The code changes look fine. Will wait to r+ until the new tests are uploaded. Thanks again for fixing (and testing) this!

[Radar WebKit Bug Importer]

<rdar://problem/68472384>

[James Darpinian]

Created attachment 408496 [details]
Patch

[EWS Watchlist]

Note that there are important steps to take when updating ANGLE. See https://trac.webkit.org/wiki/UpdatingANGLE

[James Darpinian]

Comment on attachment 408496 [details]
Patch

Test added. Still working on the upstream test as there are issues with the WebGL 1 version. We can commit this version to test the new WebGL 2 functionality and I will update the test later when the WebGL 1 version is finished.

[Kenneth Russell]

Comment on attachment 408496 [details]
Patch

Looks great! Nice work on the thorough test. In the WebKit bug, could you please link to an ANGLE bug in which those changes will be upstreamed, and make sure the conformance test changes are also upstreamed? Thanks! r+

[James Darpinian]

Comment on attachment 408496 [details]
Patch

I filed an ANGLE bug for this here: https://bugs.chromium.org/p/angleproject/issues/detail?id=5038

[EWS]

Committed r266953: <https://trac.webkit.org/changeset/266953>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 408496 [details].