Trouble generating random enum

Development Programming & Scripting
1

I have an enum to track character hair color, and I’m trying to set it to a random value. I tried doing it by casting a random uint8 as the enum in question:

//.h
UENUM(BlueprintType)
enum class EHairColor : uint8{
		Black,
		Brown,
		Blonde,
		Red,
		Dyed,
};

//.cpp
 EHairColor hair;
	uint8 randomSeed;
	randomSeed = FMath::RandRange(0,2);
	hair = Cast<EHairColor>(randomSeed);

This produces a compiler error, “None of the two overloads could convert all the argument types,” which I assume means that you can’t cast an integer into an enumeration that way- is there a preferred method for getting random enums?

2

Hmm, that eliminates the casting error I was getting, but it produces a new one, “illegal qualified name in member declaration”

3

Double reply, but I found that removing “::Type” entirely makes it compile! Thank you very much :slight_smile:

4

have you tried Static_Cast?

 //.h
 UENUM(BlueprintType)
namespace EHairColor 
{
	enum Type
	{
         Black,
         Brown,
         Blonde,
         Red,
         Dyed,
	};
}

//.cpp
	EHairColor::Type HairColor = static_cast<EHairColor::Type>( FMath::RandRange(0,2) );
5

Sorry for the multiple comments, but I added this for all the enums I’m randomizing, and it doesn’t look like it works: it compiles and runs cleanly, and it returns different results for each character, but it returns the same results every time- if a character is generated with blonde hair and green eyes, they get that pattern every single time. Is that likely down to an eccentricity of Rand?

6

the reason it didn’t compile with ::Type on the end, is because you are declaring your enum inside a class. you can either declare it outside of a class using the syntax i posted above, or you can put it inside a class and replace the namespace with a struct, but either way, you should use the scoped “::Type” method because it avoids naming conflicts.

from the UE4 coding standards document:

“Note that for locally-declared enums, you will not be able to use a namespace for scoping. In these cases, we opt to declare a local struct with no member variables, only a local enum type and use that struct for scoping.”

RandRange() should produce a random integer every time. to get the same results from a random operation, you should use random stream, which accepts a seed.

7

Thank you very much for the elaboration! :slight_smile: