1### Compilation failed: 2 3error: 3: 'main' must return: 'vec4', 'float4', or 'half4' 4void main() { 5^^^^^^^^^^^ 6error: 4: unknown identifier 'sk_FragColor' 7 sk_FragColor.x = half(packHalf2x16(a)); 8 ^^^^^^^^^^^^ 9error: 4: unknown identifier 'packHalf2x16' 10 sk_FragColor.x = half(packHalf2x16(a)); 11 ^^^^^^^^^^^^ 12error: 5: unknown identifier 'sk_FragColor' 13 sk_FragColor.x = half(packUnorm2x16(a)); 14 ^^^^^^^^^^^^ 15error: 6: unknown identifier 'sk_FragColor' 16 sk_FragColor.x = half(packSnorm2x16(a)); 17 ^^^^^^^^^^^^ 18error: 6: unknown identifier 'packSnorm2x16' 19 sk_FragColor.x = half(packSnorm2x16(a)); 20 ^^^^^^^^^^^^^ 21error: 7: unknown identifier 'sk_FragColor' 22 sk_FragColor.x = half(packUnorm4x8(b)); 23 ^^^^^^^^^^^^ 24error: 7: unknown identifier 'packUnorm4x8' 25 sk_FragColor.x = half(packUnorm4x8(b)); 26 ^^^^^^^^^^^^ 27error: 8: unknown identifier 'sk_FragColor' 28 sk_FragColor.x = half(packSnorm4x8(b)); 29 ^^^^^^^^^^^^ 30error: 8: unknown identifier 'packSnorm4x8' 31 sk_FragColor.x = half(packSnorm4x8(b)); 32 ^^^^^^^^^^^^ 3310 errors 34