UEyelinkInterface¶

A class to bridge the Eyelink C API with Unreal C++.

Syntax¶

class UEyelinkInterface : public UObject

Remarks¶

Long story short: The Eyelink library makes strong assumptions about the linearity of experiments, which cannot be satisfied in a complex OOP environment. Here we encapsulate information about the Eyelink machine in a single object. Because the Eyelink machine will make incoming calls to display calibration targets, we encapsulate these calls in delegates so that they only will be handled when needed.

Because Eyelink is in C, these delegates have to be static. Thus the class should be used as a singleton. The delegates should only be bound minimally, i.e. bind them right before we do calibration, and unbind right after. This serves two purposes. First, we minimize how much effect the Eyelink machine can have on gameplay. Second, Eyelink, being C, has no concept of object lifecycles; we use UMG to display eyetracking and those are ephemeral.

The delegate binding should be done externally. I.e. this should be a reactive-only object. Eyelink, in no circumstances, should be able to affect gameplay unless in explicit response to a function call to this object.

Lifecycles-wise, because Eyelink is C, it does not seem like the library is elegantly capable of handling start-stops / multiple instances. So this object should be used by GameInstance, which will keep everything alive for the duration of the experiment. UCLASS

Inheritance Hierarchy¶

UObject → UEyelinkInterface

Methods¶

Properties¶

Delegates¶