[Unity] TrackableResult.GetTrackable produces too much Garbage => bad performance
1. SDK Version: 4.1.4
2. Development Environment: (eg. Unity-Android, Unity-iOS, Native Android, Native iOS) Unity-Android
3. Tracker/Scanner: ImageTarget
4. License Type(Free / Pro-One Time Fee / Pro-Subscription / Enterprise): Free
5. Target Device(Optional):
While integrating MaxST as our replacement for Vuforia in an already existing application, we stumbled upon severe performance-issues on all our devices. Using the Unity-Profiler, I noticed that due to MaxST, 1 MB of Garbage was produces each frame, resulting in frequent, long invocations of the GC.
This garbage comes from the Trackable-class, which is created every frame in the call of TrackingResult.GetTrackable:
public Trackable GetTrackable(int index)
{
Trackable t;
t = new Trackable(NativeAPI.maxst_TrackingResult_getTrackable(cPtr, index));return t;
}
Incidentially, that Trackable-class contains an 1MB large array, which is thereby allocated each frame as well:
public class Trackable
{
private ulong cPtr;
private float[] glPoseMatrix = new float[16];
private byte[] idBytes = new byte[100];
private byte[] nameBytes = new byte[100];
private byte[] cloudNameBytes = new byte[100];
private byte[] cloudMetaBytes = new byte[1024*1024];
We were able to resolve the issue by creating one static Trackable-instance, whose cPtr-value was set in each GetTrackable-call:
public partial class TrackingResult
{
private static Trackable trackable = null;public Trackable GetTrackableCached(int index)
{
var trackable_cPtr = NativeAPI.maxst_TrackingResult_getTrackable(cPtr, index);if (trackable == null)
trackable = new Trackable(trackable_cPtr);
else
trackable.SetCPtr(trackable_cPtr); // custom methodreturn trackable;
}
}
We belive that this, or a similar fix should be integrated into the SDK, as the difference in performance is quite large.
Thank you for good advice. We will review this internally.
Leo
Maxst Support Team
