[wpe 2.38] No WebGL anti aliasing

[KMerzak]

Hello !
Iam using :
Cog version 0.16.1
(WPE WebKit 2.38.6) with WPEBackend-fdo
Weston/Wayland : 10.0.1 with the Toradex Veredin IMX8MPlus
The issue i have is I can't enable WebGL context property antialias ( i tried to set antialias : true but nothing changes even enabling WebGLRenderingContext: sampleCoverage() method) it is quite visible when drawing lines with gl.drawArrays with chromium antialiasing works fine
I tried to run the test : https://github.com/WebPlatformForEmbedded/WPEWebKit/blob/wpe2.38/LayoutTests/fast/canvas/webgl/antialiasing-enabled.html
and it failed on cog but passed on chromium.
Do you have any idea what might be happening ? Thanks !