Input Timing bug

Bug Reports
1

Looking into the implementations of Fuse.Gestures I noticed a bug that might lead to incorrect behaviour.

For example the class Clicker:

void OnPointerPressed(object sender, PointerPressedArgs args)
{
    ...
    _startTime = Time.FrameTime;    ...
}

void OnPointerMoved(object sender, PointerMovedArgs args)
{
    ...
    var deltaTime = Time.FrameTime - _startTime;
    ...
}

Time.FrameTime is not the time the InputEvent occured, it is the time Update is called.
On Android and iOS InputEvents provide a Timestamp which should be used instead.

To show the difference between Timestamp, FrameTime (and Clock.getSeconds) I used this snipped on iOS:

public void OnPointerMoved(object sender, PointerMovedArgs args)
{
    debug_log "Delta TimeStamp: " + ((args.Timestamp - lastTimeStamp) * 1000.0);
    debug_log "Delta FrameTime: " + (Fuse.Time.FrameTime - lastFrameTime);
    debug_log "Delta Clock: " + (Uno.Diagnostics.Clock.GetSeconds() - lastClock);

    ...
}

The table below reveals the differences for a couple of calls to OnPointerMoved

TimeStamp

FrameTime

Clock

0.016626

0.017401

0.015138

0.016558

0.015099

0.019484

0.016703

0.020304

0.018087

0.016885

0.018435

0.018644

0.016473

0

0.001563

0.016682

0.020627

0.020716

0.016843

0.03649

0.035308

0.016445

0.019969

0.017517

0.016694

0

0.00194

0.016675

0.019418

0.013313

0.016572

0.013425

0.016233

0.016688

0.016303

0.017642

Time base problem

An other problem I stumbled over when trying to fix our custom Gesture-System, is the time the different Properties are based on:

TimeStamp - is time since SystemUp

FrameTime - (not sure) since application started? Is updated on Application.Update()

Clock.getSeconds() - is time since an undefined point in time

A way to compare PointerEventArgs.Timestamp with Fuse.Time.FrameTime is needed

2

Hi!

Clock.GetSeconds() is seconds since epoch

Fuse.Time.FrameTime is the elapsed time in seconds since application started until the previously drawn frame

Fuse.Time.FrameInterval is the elapsed time in seconds between the two last frames

I will look into timestamping of inputevents tomorrow :slight_smile:

3

Wups sorry I was wrong on the Clock.GetSeconds() part

https://www.fusetools.com/learn/uno/api/uno/diagnostics/clock/getseconds