Loading fuel tanks via SimConnect

[Dutch]

Greetings fellow developers!

In my DLL application one of the things I need to do is load fuel tank quantities for the player's aircraft, and SimConnect ought to be able to to that easily. I can load all the payload stations just fine.

And indeed I can load any fuel tank quantity...but only one! Any attempt to load another tank fails to set the quantity. It doesn't seem to matter which one; the first one I set works and subsequent attempts to set others fail until...until I open up the fuel dialog box! Then, I can use SimConnect to set another tank.

It does not appear to be a timing issue. I can wait minutes between sets and it doesn't work on the 2nd one.

Does anyone know of any special thing that needs to be done between writes to fuel tanks so that they can be loaded?

Here's the code. Two test functions to load separate tanks, and I can call these from buttons on a gauge:

If 'TestFuelLoad1' gets called first, the center tank will have 100 gallons in it. A call to 'TestFuelLoad2' will not, however, put 200 gallons in the left main tank, it will stay zero UNTIL I manually bring up the fuel dialog box and observe the 100 gallons in the center tank. After this, the next call to 'TestFuelLoad2' will put the 200 gallons in the left main tank and leave the 100 in the center tank. Reverse the other of the calls and the opposite occurs, left main gets loaded and center won't -- it has nothing to do with which tank.

I realize that in this test I could set both of these with one call -- but the nature of the application is such that I need to be able to set tanks individually at different points without the user having to do anything.

Many thanks,
Dutch


void TestFuelLoad1()
{
double Value = 100;
HRESULT hr;

static enum DATA_DEFINE_ID21 {
FUELQTY1
};

hr = SimConnect_AddToDataDefinition(hSimConnect, FUELQTY1, "FUEL TANK CENTER QUANTITY", "gallons");
hr = SimConnect_SetDataOnSimObject(hSimConnect, FUELQTY1, SIMCONNECT_OBJECT_ID_USER, 0, 0, sizeof(double), &Value);

}

void TestFuelLoad2()
{
double Value = 200;
HRESULT hr;

static enum DATA_DEFINE_ID22 {
FUELQTY2
};

hr = SimConnect_AddToDataDefinition(hSimConnect, FUELQTY2, "FUEL TANK LEFT MAIN QUANTITY", "gallons");
hr = SimConnect_SetDataOnSimObject(hSimConnect, FUELQTY2, SIMCONNECT_OBJECT_ID_USER, 0, 0, sizeof(double), &Value);
}

 

[Manuel Ambulo]

Hey Dutch!

I think that you could try by defining the FUELQTY1 along with the FUELQTY2 in the same enumeration, i think that when you define the FUELQTY1 in a separated enumeration from the FUELQTY2, the program itself maybe assigning the same value (number) and as a result, when you call "SimConnect_AddToDataDefinition" and "SimConnect_SetDataOnSimObject" functions for each tank it's overwritting the same definition, because both (FUELQTY1 and FUELQTY2) have the same value (number).

Note that when im refering to *VALUE* (number) im not refering to the gallons (100 neither 200), im refering to the number assigned by the program which usually begins with 0 like an index number (because it's a enumeration) thats why maybe the second tank that you want to refuel isnt working.

When you define both IDs under the same enumeration statement, you will see that each ID has a different number:

static enum DATA_DEFINE_ID21 {
FUELQTY1, // number: 0
FUELQTY2, // number: 1
};

If you separate them, in different enumeration statements, i think you will get this:

static enum DATA_DEFINE_ID21 {
FUELQTY1, // number: 0
};

static enum DATA_DEFINE_ID22 {
FUELQTY2, // number: 0
};

Note that both have the *SAME* number, if you call the "SimConnect_AddToDataDefinition" and "SimConnect_SetDataOnSimObject" functions as it was in your original code, it will overwrite the same definition, giving as a result that you cannt set the fuel on the second tank. Remmember that you cann't use the same ID in two different definitions, as stated in the SDK.


I suggest you to try like this:

// Here i included both IDs in the same enumeration
static enum DATA_DEFINE_ID21 {
FUELQTY1,
FUELQTY2,
};


void TestFuelLoad1()
{
double Value = 100;
HRESULT hr;

hr = SimConnect_AddToDataDefinition(hSimConnect, FUELQTY1, "FUEL TANK CENTER QUANTITY", "gallons");
hr = SimConnect_SetDataOnSimObject(hSimConnect, FUELQTY1, SIMCONNECT_OBJECT_ID_USER, 0, 0, sizeof(double), &Value);

}


void TestFuelLoad2()
{
double Value = 200;
HRESULT hr;

hr = SimConnect_AddToDataDefinition(hSimConnect, FUELQTY2, "FUEL TANK LEFT MAIN QUANTITY", "gallons");
hr = SimConnect_SetDataOnSimObject(hSimConnect, FUELQTY2, SIMCONNECT_OBJECT_ID_USER, 0, 0, sizeof(double), &Value);
}

Try with it and let me know your results ...


Best Regards,


Manuel

 

[Dutch]

Thanks for your quick and detailed response, Manual.

Your suggestion has indeed fixed the problem!

I still need to wrap my head around how those enums work...sigh.

Dutch

 

[Manuel Ambulo]

Thanks for your quick and detailed response, Manual.

Your suggestion has indeed fixed the problem!

Thanks!, it's good to heard that it worked.

I still need to wrap my head around how those enums work...sigh.

Yeah, also it happened to me time ago. It took me a little while, but finally i got it (how enumerations work).


Best Regards,


Manuel

 

[jimkeir]

Hi,

The other way to do it is to clear the definition after you've used it. What you're doing now is:

- Add tank1 to definition
- Set value 1 (== tank1)
- Add tank2 to definition (so you now have tank1 *and* tank2)
- Set value 1 (== tank1)

Try using SimConnect_ClearDataDefinition before adding your values. Of course, it's probably better to just use two definitions and only set them up once each, as described above.

Cheers,
Jim