struct Inputs { float a; float b; float4 c; float4 d; }; struct Outputs { float4 sk_FragColor [[color(0)]]; }; fragment Outputs fragmentMain(Inputs _in [[stage_in]], bool _frontFacing [[front_facing]], float4 _fragCoord [[position]]) { Outputs _out; (void)_out; _out.sk_FragColor.x = abs(_in.a - _in.b); _out.sk_FragColor.x = distance(_in.c, _in.d); return _out; }