uniform half4 colorGreen, colorRed;
uniform float2x2 testMatrix2x2;

half4 main(float2) {
    bool ok = true;

    // Prefix ++ and -- (scalar int).
    int i = 5;
    ++i;
    ok = ok && (i == 6);
    ok = ok && (++i == 7);
    ok = ok && (--i == 6);
    --i;
    ok = ok && (i == 5);

    // Prefix ++ and -- (scalar float).
    float f = 0.5;
    ++f;
    ok = ok && (f == 1.5);
    ok = ok && (++f == 2.5);
    ok = ok && (--f == 1.5);
    --f;
    ok = ok && (f == 0.5);

    // Prefix ++ and -- (vector-component float).
    float2 f2 = float2(0.5);
    ++f2.x;
    ok = ok && (f2.x == 1.5);
    ok = ok && (++f2.x == 2.5);
    ok = ok && (--f2.x == 1.5);
    --f2.x;
    ok = ok && (f2.x == 0.5);

    // Prefix ++ and -- (vector float).
    ++f2;
    ok = ok && (f2 == float2(1.5));
    ok = ok && (++f2 == float2(2.5));
    ok = ok && (--f2 == float2(1.5));
    --f2;
    ok = ok && (f2 == float2(0.5));

    // Prefix ++ and -- (vector int).
    int4 i4 = int4(7, 8, 9, 10);
    ++i4;
    ok = ok && (i4 == int4(8, 9, 10, 11));
    ok = ok && (++i4 == int4(9, 10, 11, 12));
    ok = ok && (--i4 == int4(8, 9, 10, 11));
    --i4;
    ok = ok && (i4 == int4(7, 8, 9, 10));

    // Prefix ++ and -- (matrix).
    float3x3 m3x3 = float3x3(1, 2, 3, 4, 5, 6, 7, 8, 9);
    ++m3x3;
    ok = ok && (m3x3 == float3x3(2, 3, 4, 5, 6, 7, 8, 9, 10));
    ok = ok && (++m3x3 == float3x3(3, 4, 5, 6, 7, 8, 9, 10, 11));
    ok = ok && (--m3x3 == float3x3(2, 3, 4, 5, 6, 7, 8, 9, 10));
    --m3x3;
    ok = ok && (m3x3 == float3x3(1, 2, 3, 4, 5, 6, 7, 8, 9));

    // Prefix '!'
    ok = ok && !(colorGreen.r == 1.0);

    // Prefix '-' (scalar, vector, matrix float)
    ok = ok && (-1 == -colorGreen.g);
    ok = ok && (half4(0, -1, 0, -1) == -colorGreen);
    ok = ok && (float2x2(-1, -2, -3, -4) == -testMatrix2x2);

    // Prefix '-' (scalar, vector int)
    int2 iv = int2(i, -i);  // (5, -5)
    ok = ok && (-i == -5);
    ok = ok && (-iv == int2(-5, 5));

    return ok ? colorGreen : colorRed;
}