Bug 242297 – Shader fails to link due to Metal internal error

• Component: WebGL
• Status: RESOLVED CONFIGURATION CHANGED

[Pedro J. Estébanez]

Created attachment 460642 [details]
Shader GLSL source code

A shader that the Godot game engine generates, which compiles and links succesfully on every other platform supporting OpenGL ES 3 or WebGL 2, on Safari running on an iPhone fails to be linked, and the following is logged: 
[Error] Internal error compiling shader with Metal backend.
[Error] Please submit this shader, or website as a bug to https://bugs.webkit.org

[Pedro J. Estébanez]

I've been able to isolate the code line that causes the error:
float fog_far = fog_depth_end > 0.0 ? fog_depth_end : z_far;

If that line is replaced by the equivalent if-else construct, it works.

[Pedro J. Estébanez]

The aforementioned fix hasn't worked for some user, though.

[Radar WebKit Bug Importer]

<rdar://problem/96800041>

[Kimmo Kinnunen]

I think this has been fixed now with
https://bugs.chromium.org/p/angleproject/issues/detail?id=7487

[Pedro J. Estébanez]

Happy to know this is being addressed.

However, I wanted to stress that in my tests, even after replacing all the occurences of the ternary by their if-else equivalents, a new modality the issue happened: no errors reported neither at compile nor link, but the shader would still not render anything, as if there was a deeper internal issue that couldn't surface up to the user.

[Kimmo Kinnunen]

Thanks. Similar observations are being discussed in bug 237658 but it's not yet clear if these are related.

[Kimmo Kinnunen]

This should now work. If not, please reopen and attach a runnable reproduction if only possible.