Convert SpatialEventGesture location3D to Entity

Question

Created Sep ’24

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In my visionOS app I am attempting to get the location of a finger press (not a tap, but when the user first presses their fingers together). As far as I can tell, the only way to get this event is to use a SpatialEventGesture.

I've currently got a DragGesture and I am able to use the convert functions in the passed in EntityTargetValue to convert the location3D from the DragEvent to my hit tested entity. But as far as I can tell the SpatialEventGesture doesn't use an EntityTargetValue. I've tried using the convert functions in my targeted entity (ie, myEntity.convert(position: from:)) but these do not return valid values.

My questions are:

Is SpatialEventGesture the correct way to get notified of finger presses?
How do I convert the location3D in the SpatialEventGesture to my entity space?

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Answer 1

Vision Pro Engineer OP

Apple

Sep ’24

Accepted Answer

Hi @KGraus

You can convert the location of a SpatialEventGesture to the same coordinate space as an entity by using the convert(_:from:to:) method either targetedToEntity(_:) or targetedToAnyEntity() provide you with.

For example, here's how you can use targetedToEntity(_:) with a SpatialTapGesture to convert its location3D to the coordinate space of your target entity:

.gesture(
    SpatialEventGesture()
        .targetedToEntity(targetEntity)
        .onChanged { events in
            for value in events.gestureValue {
                // Convert the location3D to entity space.
                let positionInEntitySpace = events.convert(value.location3D, from: .local, to: targetEntity.parent!)
                print("Position in entity space: \(positionInEntitySpace)")
                
                // You can also get the position of the "input device" (i.e. the fingers) performing the spatial event gesture.
                if let inputPosition = value.inputDevicePose?.pose3D.position {
                    // Convert the position to scene space.
                    let pressPositionInSceneSpace = events.convert(inputPosition, from: .local, to: .scene)
                    
                    // Determine which hand is performing the gesture.
                    if value.chirality == .right {
                        print("Right hand press position: \(pressPositionInSceneSpace)")
                    } else if value.chirality == .left {
                        print("Left hand press position: \(pressPositionInSceneSpace)")
                    }
                }
            }
        }
)

This snippet also demonstrates how to get the actual press position of the fingers in scene space, just in case that is also useful for you!

1

Answer 2

KGraus OP

Sep ’24

Thank you for the reply!

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