FS2004 Kinda proud of this...

[Lane Street]

...even though it took way to long and probably looks a bit crude to the pros.

The mission: a new switch for the taxi/landing lights on the default Lear 45.

The goal: taxi lights dependent on gear position. They should only be on when the gear is down.

The code...

<Gauge Name="3WayLandingLights" Version="1.0">

  <Element>
  <Select>
    <Value>(L:3wayLLswitch,number)</Value>
  <Case Value="0">
  <Image Name="switch_off.bmp"/>
      </Case>
  <Case Value="1">
  <Image Name="switch_mid.bmp"/>
  </Case>
  <Case Value="2">
  <Image Name="switch_on.bmp"/>
  </Case>
  </Select>
  </Element>
   
  <Element>  <!--  Off  -->
     <Select>
  <Value>(L:3wayLLswitch,number) 0 == if{ 0 (&gt;K:LANDING_LIGHTS_SET) (A:LIGHT TAXI,bool) if{ (&gt;K:TOGGLE_TAXI_LIGHTS) } }</Value>
   </Select>     
  </Element>
         
  <Element>  <!-- Taxi  -->
   <Select>
    <Value>(L:3wayLLswitch,number) 1 == if{ 0 (&gt;K:LANDING_LIGHTS_SET) }</Value>
   </Select>     
  </Element>
         
  <Element>  <!-- Land  -->
   <Select>
    <Value>(L:3wayLLswitch,number) 2 == if{ 1 (&gt;K:LANDING_LIGHTS_SET) }</Value>
   </Select>     
  </Element>
         
   <Element>   <!-- Taxi  -->
    <Select>
     <Value>(L:3wayLLswitch,number) 1 == if{ (A:GEAR POSITION,percent) 75 >= if{ (A:LIGHT TAXI,bool) 0 == if{ (&gt;K:TOGGLE_TAXI_LIGHTS) } } els{  (A:LIGHT TAXI,bool) 1 == if{ (&gt;K:TOGGLE_TAXI_LIGHTS) } } }</Value>
    </Select>     
   </Element>
   
   <Element>   <!--  Land  -->
    <Select>
     <Value>(L:3wayLLswitch,number) 2 == if{ (A:GEAR POSITION,percent) 75 >= if{ (A:LIGHT TAXI,bool) 0 == if{ (&gt;K:TOGGLE_TAXI_LIGHTS) } } els{  (A:LIGHT TAXI,bool) 1 == if{ (&gt;K:TOGGLE_TAXI_LIGHTS) } } }</Value>
    </Select>     
   </Element>         
 
  <Mouse>
     <Tooltip>Taxi/Landing Lights</Tooltip>
     
   <Area Left="0" Top="0" Width="34" Height="21">   
     <Cursor Type="UpArrow"/>
     <Click>(L:3wayLLswitch,number) 2 &lt; if{ (L:3wayLLswitch,number) 1 + d (&gt;L:3wayLLswitch,number) }</Click>
   </Area>

   <Area Left="0" Top="22" Width="34" Height="21">
     <Cursor Type="DownArrow"/>
     <Click>(L:3wayLLswitch,number) 0 &gt; if{ (L:3wayLLswitch,number) 1 - d (&gt;L:3wayLLswitch,number) }</Click>
   </Area>
   
  </Mouse>
</Gauge>

Any suggestions to clean this up are appreciated.

cheers,
Lane
(still an XML newb, after all these years)

 

[tgibson]

Hi,

Only one big problem I see. When the 3wayLLswitch variable is set to a certain number, your code will be sending K: commands to the sim 18 times a second (the rate that gauge code is evaluated). This will swamp the sim with commands, and make multiple key commands impossible (like opening a second door, selecting other than engine 1, etc.). Too many of this and your frame rate will probably suffer too.

A logical solution is to move all the K: commands into the Mouse section which will only be run once, when you click the mouse.

One other thing that you can do to streamline things is instead of using 3 separate bitmaps for the knob, use only one and then a Rotate command to rotate it to the right position in each case. But separate bitmaps work too, no big problem.

Hope this helps,

 

[Lane Street]

Thanks for the advice Tom, much appreciated.

I will look at the K: commands.

As for the bitmaps, I think you can see why a rotate will not work, hehe...

cheers,
Lane

 

[Lane Street]

OK, progress has been made.

I have eliminated the spurious K: commands when the switch is in the off position, which it will be most of the time.

The challenge with moving all of the K: events to the mouse section is that doing so limits the (A:GEAR POSITION,percent) poll to once, when the gauge is clicked. I need it to continue to poll after the mouse click.

I think I can limit the polling to only happen when the gear is in transit, which should help.

Since it is only a light switch, limiting the update frequency to 1/sec will probably be OK too. (Something I did during testing, when all I could get it to do is toggle the taxi lights 18/sec, thought I was gonna have a seizure.)

For now, Easter dinner beckons, so Happy Easter to those who celebrate it and Happy Sunday to those that don't.

cheers,
Lane

 

[jeroen79]

I would use an L:var (bool) to store the desired state of the taxilight and use the mouse section only to set that L:var on and off.
Then the code inside an element that is evaluated each frame compares the desired state to the actual state and if they are not the same toggles the taxilight:
(A:gear position, percent) 50 > (L:taxilight_set, bool) && (A:taxilight, bool) == ! if{ (>K:toggle taxilight) }
The code will run 18 times/sec but the command is only sent when the actual state and desired state do not match.

You can also use one <Element><Select><Value>... structure for all code.

 

[Lane Street]

OK, changing...

(L:3wayLLswitch,number) 1 == if{ 0 (>K:LANDING_LIGHTS_SET) }

...to...

(L:3wayLLswitch,number) 1 == if{ (A:LIGHT LANDING, bool) if{ 0 (>K:LANDING_LIGHTS_SET) } }

...took care of the continuous K:events

Hi Jeroen, thanks for commenting.

I would use an L:var (bool) to store the desired state of the taxilight and use the mouse section only to set that L:var on and off.
Then the code inside an element that is evaluated each frame compares the desired state to the actual state and if they are not the same toggles the taxilight:
(A:gear position, percent) 50 > (L:taxilight_set, bool) && (A:taxilight, bool) == ! if{ (>K:toggle taxilight) }
The code will run 18 times/sec but the command is only sent when the actual state and desired state do not match.

Sorry, Jeroen, I cannot see how that is any different than...

(L:3wayLLswitch,number) 1 == if{ (A:GEAR POSITION,percent) 75 >= if{ (A:LIGHT TAXI,bool) 0 == if{ (>K:TOGGLE_TAXI_LIGHTS) } } els{  (A:LIGHT TAXI,bool) 1 == if{ (>K:TOGGLE_TAXI_LIGHTS) } } }

If L:Var = 1 then

if gear more than 75% extended then

if taxi lights are off then

toggle taxi lights.

If any of those answers are false the code stops before the K: event.

You used ands, I used ifs, does the sim care?

You can also use one <Element><Select><Value>... structure for all code.

Yeah, I split it up like that to make it easier for me to read while testing.

This gauge went through several iterations before I figured out one that would work and I wanted to make sure that fixing one aspect of the gauge didn't break another.

I added <Update Frequency="4"/> to lessen the A:Var polling, I tried <Update Frequency="1"/> and noticed an occasional, noticeable delay in switch response.

Thanks for all the help so far.

cheers,
Lane

 

[tgibson]

Yes, your code does the same thing, but:

1. It's harder to read
2. It's longer.

 

[n4gix]

This:

(L:3wayLLswitch,number) 1 == if{ (A:LIGHT LANDING, bool) if{ 0 (>K:LANDING_LIGHTS_SET) } }

is the same as this:

(L:3wayLLswitch,number) 1 == (A:LIGHT LANDING, bool) and if{ 0 (>K:LANDING_LIGHTS_SET) }

 

[Lane Street]

This:

(L:3wayLLswitch,number) 1 == if{ (A:LIGHT LANDING, bool) if{ 0 (>K:LANDING_LIGHTS_SET) } }

is the same as this:

(L:3wayLLswitch,number) 1 == (A:LIGHT LANDING, bool) and if{ 0 (>K:LANDING_LIGHTS_SET) }

OK, I can see that.

Is there any advantage to one method over the other? Other than your method has one less character?

 

[Anthony31]

Pick the method that is more readable to you. Not only now but in 6 months down the track when you've forgotten what the code was trying to do.

If you were doing a thousand of these every frame then you would need to worry about whichever was quicker (and as we are talking about XML then it's anyone's guess as to which is the quicker method) but if you're only doing a handful of these then readability (and therefore debugability) is more important.

Of course, with multiple if statements keeping count of the curly brackets can start to become a real headache.

Personally when using if statements I like to neatly space them out over multiple lines as one continuous line of nested if statements is about as unreadable as you can get.