iOS 15 webgl shader crash

20 September 2021 08:41

We have been using B4W for a few years now, and didn't feel the urge to change as it worked really well.
We use version 17.12, because the latest 18.05 introduced some performance problems, but other than that no problems until the day.
We know as well it has been a while without updates nor movement around here, but maybe there are some people that may be able to help us.

The fact is that the new iOS 15 update makes the application crash, and it seems to be something related to the webgl shader.
We have been testing around, though low level GLSL is not precisely our thing, and we have obtained some insights.
The main error from B4W says: Shader compilation/linking error: postprocessing/postprocessing.glslv, postprocessing/postprocessing.glslf, materials: ""
Throwing some logs around, we see that at the "init_shader" function, "gl.getError()" returns a "INVALID_OPERATION" after "gl.linkProgram".
Then, "gl.getProgramInfoLog(program)" shows a not very useful but human readable error: Internal error compiling shader with Metal backend. Please submit this shader, or website as a bug to
We will submit the bug there just in case, and if this post receives some kind of response I will copy here the link to it as well for reference.

We have been trying to mess with the shader, apparently everything is correct but they must have changed something on the way the process it and even removing all "postprocessing.glslf" logic (leaving only an assignment to a plain color) won't work.

Here you can find a link to our main app with a slightly modified version of the B4W engine, just to show extra debug logs on console:

We hope somebody can help us, please.

Best regards,
21 September 2021 08:33
Just in case someone finds this useful, here the link to the bug report:

It seems to be fixed already, I will test once the update is available.
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