The background: I have a tile entity which can sometimes (depending on how it's configured by the player) be a redstone power provider, and sometimes (probably more commonly) not.

 

When it's a power provider, I obviously want Block#canProvidePower() to return true.  But when it isn't a power provider, I want that method to return false (having it return true messes up things like propagating a strong redstone signal).

 

Now, canProvidePower() only takes an IBlockState parameter, so I don't have access to the tile entity to see if it's currently able to provide power.  Therefore I figured I'd probably need to store ability that in the blockstate, i.e. have the tile entity update a boolean property of the block when its ability to provide power is toggled.

 

I don't want to use a regular listed block property, because a) this property has no bearing on the rendering of the block, and b) I already have several listed properties which do affect the rendering, and I don't want to double the number of models by adding another boolean property.

 

So, my question: is IUnlistedProperty the right way to go here?  My research so far suggests that it's really intended (along with Block#getExtendedState) only for block rendering, so would this be an appropriate usage?  Or is there a better way to do this?

No, you should use the normal PropertyBool and in your ClientProxy in PreInit you need to call ModelLoader.setCustomStateMapper(yourBlockInstance, new StateMapBase.Builder.ignore(booleanPropertyToIgnore).build()).

Works nicely, thanks   One very minor note: it's

StateMap.Builder

rather than

StateMapBase.Builder

.

Yeah, I didn't have the source at hand at that moment.