<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE bugzilla SYSTEM "https://bugs.webkit.org/page.cgi?id=bugzilla.dtd">

<bugzilla version="5.0.4.1"
          urlbase="https://bugs.webkit.org/"
          
          maintainer="admin@webkit.org"
>

    <bug>
          <bug_id>238022</bug_id>
          
          <creation_ts>2022-03-17 07:18:54 -0700</creation_ts>
          <short_desc>WebGl incorrect rendering on 15.4 using Playcanvas</short_desc>
          <delta_ts>2022-03-28 17:43:18 -0700</delta_ts>
          <reporter_accessible>1</reporter_accessible>
          <cclist_accessible>1</cclist_accessible>
          <classification_id>1</classification_id>
          <classification>Unclassified</classification>
          <product>WebKit</product>
          <component>WebGL</component>
          <version>Safari 15</version>
          <rep_platform>All</rep_platform>
          <op_sys>iOS 15</op_sys>
          <bug_status>RESOLVED</bug_status>
          <resolution>FIXED</resolution>
          
          
          <bug_file_loc></bug_file_loc>
          <status_whiteboard></status_whiteboard>
          <keywords>InRadar</keywords>
          <priority>P2</priority>
          <bug_severity>Major</bug_severity>
          <target_milestone>---</target_milestone>
          <dependson>238196</dependson>
          
          <everconfirmed>1</everconfirmed>
          <reporter name="Martin">mvaligursky</reporter>
          <assigned_to name="Nobody">webkit-unassigned</assigned_to>
          <cc>avpeery</cc>
    
    <cc>dino</cc>
    
    <cc>djg</cc>
    
    <cc>gman</cc>
    
    <cc>kbr</cc>
    
    <cc>kkinnunen</cc>
    
    <cc>kpiddington</cc>
    
    <cc>webkit-bug-importer</cc>
          

      

      

      

          <comment_sort_order>oldest_to_newest</comment_sort_order>  
          <long_desc isprivate="0" >
    <commentid>1852267</commentid>
    <comment_count>0</comment_count>
    <who name="Martin">mvaligursky</who>
    <bug_when>2022-03-17 07:18:54 -0700</bug_when>
    <thetext>WebGl rendering on 15.4 has some major problems using Playcanvas engine. This has not been the case on 15.3.

Repro steps:   https://playcanvas.github.io/#/graphics/area-picker

also these additional examples (available on the same url) have similar problems, some don&apos;t render at all:
- all anim blend trees + few more anim ones
- area picker
- clustered area lights
- grab pass
- post effects

tested on iphone XR 15.4 and also on Safari 15.4 Mac OS. Both WebGl1 and WebGl2.

A possible workaround seems to be disabling of antialiasing (which means passing { antialias: false } to canvas.getContext as an option when initializing WebGl.
Most of these examples do some form of rendering to texture and then using the results, but other examples using rendering to texture seems fine.

our tracking ticket: https://github.com/playcanvas/engine/issues/4136

Possibly related to:
https://bugs.webkit.org/show_bug.cgi?id=237906
https://bugs.webkit.org/show_bug.cgi?id=237006</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1852302</commentid>
    <comment_count>1</comment_count>
    <who name="Anna from Mapbox">avpeery</who>
    <bug_when>2022-03-17 08:20:08 -0700</bug_when>
    <thetext>We had an issue with webGL rendering with the 15.4 upgrade (on iOS as well), and have also found disabling antialiasing to resolve the rendering problem. 
https://bugs.webkit.org/show_bug.cgi?id=237918</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1852875</commentid>
    <comment_count>2</comment_count>
    <who name="Radar WebKit Bug Importer">webkit-bug-importer</who>
    <bug_when>2022-03-18 16:17:02 -0700</bug_when>
    <thetext>&lt;rdar://problem/90509311&gt;</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1853041</commentid>
    <comment_count>3</comment_count>
    <who name="Kenneth Russell">kbr</who>
    <bug_when>2022-03-19 21:38:41 -0700</bug_when>
    <thetext>Can confirm that on an M1 MacBook Pro with Safari Technology Preview Release 141 (Safari 15.4, WebKit 17614.1.3.8), this example doesn&apos;t render correctly with &quot;WebGL on Metal&quot; enabled. It does render correctly with it disabled.

It renders correctly on Chrome Canary 102.0.4952.2 (Official Build) canary (arm64) with --use-angle=metal, so this bug has been fixed in top-of-tree ANGLE.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1853586</commentid>
    <comment_count>4</comment_count>
    <who name="Kimmo Kinnunen">kkinnunen</who>
    <bug_when>2022-03-22 02:41:30 -0700</bug_when>
    <thetext>Thanks for the report.
I think this is part of the 15.4 msaa regression, linked to in the depends on -section.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1855858</commentid>
    <comment_count>5</comment_count>
    <who name="Dean Jackson">dino</who>
    <bug_when>2022-03-28 17:43:18 -0700</bug_when>
    <thetext>Fixed in the ANGLE roll https://bugs.webkit.org/show_bug.cgi?id=238171</thetext>
  </long_desc>
      
      

    </bug>

</bugzilla>