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AppGameKit Classic Chat / GetRawTouchCurrentX() returns 0.0 when GetPointerstate() = 1 and finger is not at 0.0

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Dale Schultz
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Joined: 1st Nov 2021
Location: Maine, USA
Posted: 25th Nov 2021 01:35 Edited at: 25th Nov 2021 03:07
I am trying to understand why this is happening. I have some code below that looks for a swipe left or right.

I only look at the touch position if GetPointerstate()

During the touch event GetRawTouchCurrentX() returns correct values. However, after the finger is lifted, it returns a zero even while GetPointerstate() is still true.
I expect GetRawTouchCurrentX() to return actual values until GetPointerstate() returns zero.

Here is the code the demonstrates the issue:



When running the code, swipe your finger left or right, it can be seen that the swipe value is correct DURING the touch event but as soon as the event ends, it is always negative, even if you moved from left to right.
This is because GetRawTouchCurrentX() returned a zero and the original start position is subtracted from zero.

If you then uncomment the if and endif that checks for GetRawTouchCurrentX() returning 0.0 the code works as one would expect.
Even if one inspects the return value of GetPointerstate() after GetRawTouchCurrentX() one sees it is still non-zero so it not that the finger is being lifted between the execution of the GetPointerstate() and GetRawTouchCurrentX() calls.

Note that when moving the finger from left to right, and the initial position (tx) is positive, at no time is the finger ever at x position zero. Yet GetRawTouchCurrentX() returns 0.0

Excluding iterations where GetRawTouchCurrentX() = 0.0 avoids the problem for most cases but of course would fail if GetRawTouchCurrentX() is supposed to be zero.

This happens to me on Android 12

Can others reproduce this?
Am I missing something ?

The problem may be that GetPointerstate() is returning true for too long.
Dale Schultz
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Joined: 1st Nov 2021
Location: Maine, USA
Posted: 25th Nov 2021 02:37
well,


works much better!
I guess GetRawTouchReleased( ) is more responsive.

It implies that GetRawTouchReleased( ) and GetPointerstate() can both be true at the same time, but I have not tested that.
PartTimeCoder
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Location: London UK
Posted: 25th Nov 2021 16:18
Bear in mind, Touch functions use dedicated touch libs, Pointer use wrapped generic OS libs ....

GetPointerState wrote: "This is an emulated input method that uses whatever device inputs are available to produce a screen pointer."


I would not expect GetPointerState to be compatible with Touch functions without producing some side effects, use all RawTouch



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Game_Code_here
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Posted: 26th Nov 2021 21:37
Quote: "after the finger is lifted, it returns a zero"


This is when flags are important I believe.

So holding a value in a different flag might help.

if GetPointerstate()=1 then mypointflag=1

if mypointflag=1
do what ever
endif

Your saying

while GetPointerstate()=1

So for the state to be always active



Dale Schultz
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Joined: 1st Nov 2021
Location: Maine, USA
Posted: 26th Nov 2021 22:32 Edited at: 26th Nov 2021 22:36
Quote: "if GetPointerstate()=1 then mypointflag=1"


well keeping a copy of the fact that the pointer was down in a separate flag, that never gets updated, would mean the loop would repeat forever. The object of the while loop is to only loop while the pointer is pressed.

So your suggestion would be the same at



We don't want to only loop forever, only while the pointer is down. We need to loop until the pointer is released so that we can get the x coordinate.
The bugs is that after we are told the pointer is still down, after it has in fact been released, so we then we get an incorrect value of the pointer X coordinate.
We cant keep a copy of the last 'good' return value because we don't know when it is the last good call.
The workaround for the bug is to check if we get a zero and ignore that value. That workaround would, however, fail if the correct result happened to be a zero.
Virtual Nomad
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Posted: 27th Nov 2021 00:00 Edited at: 27th Nov 2021 00:06
this might help with Swipes: https://forum.thegamecreators.com/thread/195049

i think it's part of the larger Useful Community Functions (UCF) project listed referenced HERE.

meanwhile THIS re: inertia scroll/swipes mentions an android "bug" that was "fixed".
Game_Code_here
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Posted: 27th Nov 2021 02:07
Quote: "We don't want to only loop forever"


Yes and this is a good way to stop the loop

If pointerisrelesed=1 then mypointflag=0

I understand where your going but if I had to do this and I have lately this is what I did.

Dale Schultz
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Joined: 1st Nov 2021
Location: Maine, USA
Posted: 27th Nov 2021 02:54
Quote: "If pointerisrelesed=1 then mypointflag=0"


There is no pointer release function. As I mentioned above there is a GetRawTouchReleased() function which does not return a false result (but does not work with a mouse on Windows)

All your code is doing is making a copy of the bad data. Using a copy of the bad data will not make a difference.
The workaround using the 'pointer' call is to check for a zero value and ignore it.

As as I said, I could also get it to work with GetRawTouchReleased() but because of the platform limitation of rawtouch calls, I have gone back to using 'pointer' and check for zero.

Part of the aim of this post is to check that I have not made a stupid coding error before writing up a bug report. It helps to have other eyes pick up something I have missed.

@VirtualNomad, thanks, I'll check out those links and bug to see if they are related before submitting a bug.
Game_Code_here
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Posted: 27th Nov 2021 03:00
GetRawMouseReleased() is what I use, it works the same way on all devises I've tested it on.

Mabey it will work, I don't know.

I find it funny how there is raw mouse and raw touch commands that do the same things.
Dale Schultz
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Location: Maine, USA
Posted: 27th Nov 2021 03:17 Edited at: 27th Nov 2021 03:18
Indeed, it looks like IronManhood ran into the same bug:

Quote: "Edit: Found a bug. Seems like on android it takes an extra frame to reset the pointer button commands."


This describes the same symptom.

I suspect that by
Quote: "Edit: Fixed."

he means he also worked around the problem, not that the bug got fixed.

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