From pub...@  Thu Oct 21 10:36:30 2021
From: pub...@ (Mark Schlosser (...@...))
Date: Thu, 21 Oct 2021 13:36:30 -0400
Subject: [Public WebGL] WebGL full-float (32-bit) texture rendering failing on iOS>=15 Safari  for non-M1 iOS devices
Message-ID: <CAJZCPrRcAB_=wsgm==GRZy1KFKHHkvt6Q-TO-G=EGXNb_e4bbg@mail.gmail.com>

I have not managed to narrow this down to a barebones example yet, but for
now I wanted to see if anyone else has run into this issue.

With the introduction of iOS 15, WebGL2 support has come to iOS Safari.
Along with that, support for rendering to full-float (32-bit) textures has
been added.  Our renderer uses floating point texture rendering for
transparency and shadows.  Previous to iOS 15, we used half-float textures
on iOS browsers for these effects.  This worked fine.

WIth the upgrade to iOS 15, full-float texture rendering is available, but
does not appear to work for our techniques on non-M1 iOS devices with
iOS>=15 installed (full float rendering looks like it works fine on M1 iOS
devices).  For now, we plan to fall back to half-floats, since they still
appear to work fine on all iOS devices.

I want to try to see if I can create a standalone WebGL example that
reproduces this.  If I manage to do that, I can file a WebKit bug.
For now, though, I am curious if anyone else has run into this.
Thanks!