[carlm]

There is an error in the X-Plane command system.
For maximum clarity I'll state it several different ways.

STATEMENT 1
-----------

No matter how quickly one presses and releases a key/button, the command always receives at least one xplm_CommandContinue event. It's very difficult to get just one. A typical key/button press-and-release generates two or three xplm_CommandContinue events. I have a (Windows) test plugin that demonstrates this.

STATEMENT 2
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Any command which executes upon receipt of xplm_CommandContinue will typically execute at least two or three times. It's very difficult to get it to execute just once.

STATEMENT 3
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Any command which is repeat-enabled typically executes at least two or three times.

STATEMENT 4
-----------

Repeating keys typically behave as if the keyboard has autorepeat with zero delay before repeat starts.

END OF ALTERNATE STATEMENTS

CONSEQUENCE OF ERROR
--------------------

It is very difficult to get fine key/button control of many functions, including but not limited to setting {throttle, props, mixture}, rotating views with arrow keys, etc.

This behavior began in version 8.60.

PROPOSED SOLUTION
-----------------

Implement an autorepeat timer (approx 0.25 to 0.5 sec). Start the timer on xplm_CommandBegin. Do not deliver xplm_CommandContinue events to commands until the timer has timed out.

NOTE
----

I first reported this issue in a bug report with subject something like "Keyboard autorepeat with zero delay" during the 8.60 beta cycle. I never got a response.

[Sandy Barbour]

Hi carlm

This is news to me so I assume that you are talking about a bug in the Xplane Commmand implementation and not in our plugin SDK 2.00 command API?

[carlm]

That's correct, Sandy. As far as I know the error is not in the SDK: it involves how X-Plane notifies command handlers about key/button events.

[Sandy Barbour]

carlm, on 03 November 2009 - 07:07 PM, said:

That's correct, Sandy. As far as I know the error is not in the SDK: it involves how X-Plane notifies command handlers about key/button events.

Ok, so this is what our SDK glue gets from Xplane as we don't do a lot in the SDK.
Also there was no commands in Xplane prior to V9, we only added support in SDK 2.00 when V9 came out.
I have passed this info on to Ben as we both work on the SDK.

I am very surprised that you did not hear anything back from LR, even if it was negative.

[carlm]

Thanks, Sandy.

[Sandy Barbour]

carlm, on 03 November 2009 - 07:29 PM, said:

Thanks, Sandy.

That is OK.
But posting something like this here can set alarm bells ringing about the state of our SDK.