uniform half4 input;
uniform half4 colorGreen, colorRed;

half4 main(float2 coords) {
    const half4 constVec = half4(20, 0, 0, 0);
    half4 expectedVec = half4(1, 0, 0, 0);

    return (normalize(input.x)            == expectedVec.x       &&
            normalize(input.xy)           == expectedVec.xy      &&
            normalize(input.xyz)          == expectedVec.xyz     &&
            normalize(input.xyzw)         == expectedVec.xyzw    &&
            normalize(constVec.x)         == expectedVec.x       &&
            normalize(constVec.yx)        == expectedVec.yx      &&
            normalize(constVec.zxy)       == expectedVec.zxy     &&
            normalize(constVec.xyzw)      == expectedVec.xyzw) ? colorGreen : colorRed;
}