Shader looks different on Android (two devices; GLES2)

[LinuxUserGD]

Godot version:
master

OS/device including version:
Android (zerofltexx Ressurrection OS 9.0; matissewifi Lineage OS 7.1)

Issue description:
While the shader looks correct on my smartphone, on my tablet with lineage os there are strange rectangles.

Steps to reproduce:

Minimal reproduction project:
Solus-Stunts-v1.0-bug.zip

[akien-mga]

Could you retrieve OpenGL ES capabilities of both devices with this app? https://play.google.com/store/apps/details?id=de.saschawillems.glescapsviewer
It lets you upload the report from within the app which can then link from opengles.gpuinfo.org (the upload function might give an error, but it seems to work nevertheless).

[LinuxUserGD]

It worked.
zerofltexx: https://opengles.gpuinfo.org/displayreport.php?id=3503
matissewifi: https://opengles.gpuinfo.org/displayreport.php?id=3504
Both devices support OpenGL ES 3 but I'm using GLES2.
This is the shader:
https://codeberg.org/HugeGameArtGD/Solus-Stunts/raw/branch/dev-new/source/tracks/3/shader/Splatmap.gdshader

[clayjohn]

Is this still reproducible in 3.1.2 or 3.2beta?

[LinuxUserGD]

I can still reproduce it using Godot 3.2.1 stable.

[LinuxUserGD]

I tried it on linux with android one click deploy and changed texture import from vram to lossy but this didn't fix it:
First try:
Linux:

Android:

Second try (without albedo color param):
Linux:

Android:

And those are the textures assigned to the shader param:

So expected would be that the terrain texture (called "splatmap" in this case) is displayed when far away and the detailed grass albedo texture together with roughness and normal blends over the terrain where the car drives.

Maybe mipmaps don't work in GLES2 on this device or just multiplying the texture uv and repeating doesn't work.

Edit: I still need to add a minimal reproduction project later to only display the shader as for now it's part of the game. But should be possible to assign the shader/material to any mesh for trying to reproduce this issue.

[akien-mga]

Is this still reproducible in 3.3 or later?

A minimal reproducible project would be useful, though even then it might be tricky to debug as this issue likely only happens with devices which lack support for some features or have driver bugs (bugs which might be even more prominent on unofficial ROMs like LineageOS).

[Calinou]

Those artifacts may be due to the more limited shader precision available on mobile devices. See godotengine/godot-proposals#1747. In the meantime, you can detect whether the host OS is a mobile platform using OS.has_feature("mobile") and use a simpler shader.