1### Compilation failed: 2 3error: 1: 'main' must return: 'vec4', 'float4', or 'half4' 4uniform float a; int b; void main() { sk_FragColor.x = half(ldexp(a, b)); } 5 ^^^^^^^^^^^ 6error: 1: unknown identifier 'sk_FragColor' 7uniform float a; int b; void main() { sk_FragColor.x = half(ldexp(a, b)); } 8 ^^^^^^^^^^^^ 9error: 1: unknown identifier 'ldexp' 10uniform float a; int b; void main() { sk_FragColor.x = half(ldexp(a, b)); } 11 ^^^^^ 123 errors 13