resources/sksl/shared/Enum.sksl

// Declare a user enum.
enum class E {
    kZero      = 0,
    kOne       = 1,
    kTwo       = 2,
    kThree     = 3
};

void main() {
    // Test that the user enum is subject to the same optimizations as a plain int.
    const E e = E::kZero;
    if (e == E::kZero)  { sk_FragColor = half4(1); }
    @if (e == E::kZero) { sk_FragColor = half4(2); }
    @if (e != E::kZero) { sk_FragColor = half4(3); }
    if (e == E::kOne)   { sk_FragColor = half4(4); }
    @if (e == E::kOne)  { sk_FragColor = half4(5); }
    @if (e != E::kOne)  { sk_FragColor = half4(6); }

    sk_FragColor = (e == E::kZero) ? half4(7)  : half4(-7);
    sk_FragColor = (e != E::kZero) ? half4(8)  : half4(-8);
    sk_FragColor = (e == E::kOne)  ? half4(9)  : half4(-9);
    sk_FragColor = (e != E::kOne)  ? half4(10) : half4(-10);

    switch (e) {
        case E::kZero: sk_FragColor = half4(11); break;
        case E::kOne:  sk_FragColor = half4(12); break;
    }
    @switch (E::kZero) {
        case E::kZero: sk_FragColor = half4(13); break;
        case E::kOne:  sk_FragColor = half4(14); break;
    }

    // Test that built-in enums work equally well.
    const SkBlendMode m = SkBlendMode::kClear;
    if (m == SkBlendMode::kClear)  { sk_FragColor = half4(15); }
    @if (m == SkBlendMode::kClear) { sk_FragColor = half4(16); }
    if (m == SkBlendMode::kSrc)    { sk_FragColor = half4(17); }
    @if (m != SkBlendMode::kDst)   { sk_FragColor = half4(18); }

    sk_FragColor = (m == SkBlendMode::kClear) ? half4(19)  : half4(-19);
    sk_FragColor = (m != SkBlendMode::kSrc)   ? half4(20)  : half4(-20);

    @switch (SkBlendMode::kClear) {
        case SkBlendMode::kClear: sk_FragColor = half4(21); break;
        case SkBlendMode::kSrc:   sk_FragColor = half4(22); break;
        case SkBlendMode::kDst:   sk_FragColor = half4(23); break;
    }

    // Test with a non-const enum.
    E f = E::kOne;
    if (f == E::kOne) { sk_FragColor = half4(1); }
    if (f != E::kOne) { sk_FragColor = half4(4); }

    sk_FragColor = (f == E::kZero) ? half4(7)  : half4(-7);
    sk_FragColor = (f != E::kZero) ? half4(8)  : half4(-8);
    sk_FragColor = (f == E::kOne)  ? half4(9)  : half4(-9);
    sk_FragColor = (f != E::kOne)  ? half4(10) : half4(-10);

    switch (f) {
        case E::kZero: sk_FragColor = half4(11); break;
        case E::kOne:  sk_FragColor = half4(12); break;
    }
}