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On 23/11/2016 12:51, Bald Eagle wrote:
> Mike Horvath <mik### [at] gmail com> wrote:
>> I have the following three functions:
>>
>> #declare correctRGB_R = function(R,G,B) {min(max(R,0),1)}
>> #declare correctRGB_G = function(R,G,B) {min(max(G,0),1)}
>> #declare correctRGB_B = function(R,G,B) {min(max(B,0),1)}
>>
>> They each process input and output one component of an R,G,B color vector.
>>
>> However, instead of the above, I want the entire vector discarded if
>> *any* of R, G or B is less than zero or greater than one.
>>
>> I'm not sure how to form the select statement. What is the best way to
>> do this?
>>
>> Mike
What do you mean by discarded? A function must always return a value,
there is no "discarded" option. Where/how are you going to use these
three functions and what do you want the final result to be if the input
RGB is out of range? You could return a special value like -1 to
indicate a "discarded" vector - but it depends what you're going to do
next with the result.
> Wrap all three #declares in a conditional block?
>
> #if (R>1 | R<0 | G>1 | G<0 | B>1 | B<0)
> // do nothing, or whatever else you want
> #else
> #declare correctRGB_R = function(R,G,B) {min(max(R,0),1)}
> #declare correctRGB_G = function(R,G,B) {min(max(G,0),1)}
> #declare correctRGB_B = function(R,G,B) {min(max(B,0),1)}
> #end
>
> or something along those lines....
That's just going to decide whether or not to declare the functions in
the scene, on some unrelated RGB variables (RGB in the function
definitions are just parameters). It won't affect the behaviour of the
function when it is actually used later on (apart from getting an error
that it is undefined).
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