The unhandled error message below looks to be due to using GLSL ES versions below 3.00. Was discussed in this post from 2017:
PBR sample build problems on Android - Discussions / Support - Urho3D
Is there any way round this? And if there were, is there any point trying to use PBR on Android, or will the performance hit make it pretty useless?
Failed to compile pixel shader PBRLitSolid(IBL PBR):
ERROR: 0:20030: '-' : wrong operand types - no operation '-' exists that takes a left-hand operand of type 'const int' and a right operand of type 'mediump float' (or there is no acceptable conversion)
ERROR: 0:20030: 'pow' : no matching overloaded function found
ERROR: 0:20030: '*' : wrong operand types - no operation '*' exists that takes a left-hand operand of type 'const int' and a right operand of type 'const mediump float' (or there is no acceptable conversion)
ERROR: 0:20030: '+' : wrong operand types - no operation '+' exists that takes a left-hand operand of type 'mediump float' and a right operand of type 'const int' (or there is no acceptable conversion)
ERROR: 0:109: '1.0f' : Floating-point suffix unsupported prior to GLSL ES 3.00
ERROR: 0:109: '1.0f' : syntax error