1### Compilation failed: 2 3error: 3: 'main' must return: 'vec4', 'float4', or 'half4' 4void main() { 5^^^^^^^^^^^ 6error: 4: unknown identifier 'sk_FragColor' 7 if (unknownInput > 5) { sk_FragColor = half4(0.75); } else { discard; } 8 ^^^^^^^^^^^^ 9error: 4: discard statement is only permitted in fragment shaders 10 if (unknownInput > 5) { sk_FragColor = half4(0.75); } else { discard; } 11 ^^^^^^^ 12error: 6: unknown identifier 'sk_FragColor' 13 while (i < 10) { sk_FragColor *= 0.5; i++; } 14 ^^^^^^^^^^^^ 15error: 7: unknown identifier 'sk_FragColor' 16 do { sk_FragColor += 0.25; } while (sk_FragColor.x < 0.75); 17 ^^^^^^^^^^^^ 18error: 7: unknown identifier 'sk_FragColor' 19 do { sk_FragColor += 0.25; } while (sk_FragColor.x < 0.75); 20 ^^^^^^^^^^^^ 216 errors 22