# NsdkSessionDataSource

Source: https://www.nianticspatial.com/docs/api/kotlin/com.nianticspatial.nsdk.NsdkSessionDataSource/

NsdkSessionDataSource

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## Declaration

interface NsdkSessionDataSource

## Summary

Provides synchronous, pull-based access to the latest available sensor data
required by [NSDKSession].
All methods must be non-blocking and thread-safe. Returned values represent
the most recent samples already captured by the underlying services.
Implement this interface and assign it to [NSDKSession.dataSource], then call
[NSDKSession.update] once per camera frame to submit data to the native layer.

## See also

DefaultSessionDataSource -- for the standard ARCore + sensor implementation.
PlaybackSessionDataSource -- for dataset playback.

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## Functions

| Name | Type | Summary |
| --- | --- | --- |
| latestCameraSample | CameraSample? | Returns the most recent camera sample, or null if unavailable. |
| latestCompassSample | Compass? | Returns the most recent compass/magnetometer reading, or null if unavailable. |
| latestDepthSample | DepthSample? | Returns the most recent platform depth sample (e.g. LiDAR), or null if unavailable. |
| latestGpsSample | Location? | Returns the most recent GPS location, or null if unavailable. |
| latestTrackingStateSample | TrackingState | Returns the current VIO tracking state. |
| prepareFrame | Boolean | Snapshots the current frame data so that [latestCameraSample] and the other accessorscan be called from any thread. Returns true when a frame is ready to be consumed, falseif no frame was available -- in which case the caller should skip [NSDKSession.update].The default implementation returns true and does nothing; data sources that hold noper-frame state do not need to override it.**Threading contract**: the caller must ensure that [prepareFrame], [NSDKSession.update],and any `latest*` accessor calls are serialized -- i.e., a complete`prepareFrame -> update -> (accessors finish)` cycle must complete before the next[prepareFrame] call begins. This is typically achieved by driving the cycle from asingle-threaded executor or a coroutine with an in-flight gate. |

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