P3D v4 Using a variable for FloatPosition doesn't seem to work...

[Jason210]

Instead of using literals like this

<FloatPosition>20.000, 40.000</FloatPosition>

I want to use

FloatPosition>(L:Xoff,number),(L:Yoff,number)</FloatPosition>

However, this is not positioning the element according to the values in the variables. Anyone know how to approach this?

 

[rpmc]

Can't use variables in FloatPosition. Use <Shift><Scale><Expression>together with fixed number FloatPosition instead. The G1000 mfd gauge has examples.

Bob

 

[Jason210]

Hi & thanks.

I looked at that earlier but it still requires that you actually specify float values in the non-linearity table. My variables are random offsets, and are set when the panel is opened and don't change until it is closed and opened again. No interpolation is required as this is not for an animation. The random offsets are meant to determine new coordinates to draw a line on a map at an position offset from the centre. Perhaps this is not possible in XML gauges. It would really help if I could find an explanation of all the properties of that tag.

 

[Jason210]

Let's say I have a float position of 380, 380. I want to then add to these Xoff and Yoff. How would I do that using Shift? How do you specify x and y? I've tried a lot of stuff.

 

[rpmc]

I've tried a lot of stuff.

but I don't think you looked at the G1000 mfd gauge, and it's written using FSX schema format which you will need to use.

You must use <Shift> to move objects in XML. Search this forum for "Shift" and you'll find lots of discussion, like this and this, which is written in FS9 schema format but you can figure out the FSX equivalent syntax.

 

[Jason210]

It seems that in the FSX schema, the scale is a multiplier array for x and y, so <Scale>1.000, 0.000</Scale> means multiply x by 1, and y by 0. This effectively moves it in the x-axis. Similarly <Scale>0.000, 1.000</Scale> means multiply x by 0, and y by 1, with the result of moving it in the y-axis. So the general approach for moving something by an offset amount is:

            <Shift id="Shift">
                <Scale>1.000,0.000</Scale>
                    <Expression id="Expression">
                        <Script>(L:Xoffset,number)</Script>
                    </Expression>
            </Shift>
            <Shift id="Shift">
                <Scale>0.000,1.000</Scale>
                    <Expression id="Expression">
                        <Script>(L:Yoffset,number)</Script>
                    </Expression>
            </Shift>

This works.

However, I notice that this shifting takes place along the element's local coordinate system, as opposed to the coordinate system of the map. This is not a problem to correct unless the element gets rotated, which in my case it will be. I know I could use some trigonmetry to correct this, but that would be a complicated and messy fix. Do you know of a simpler way?

 

[rpmc]

<Rotation> Use it in the same <Element> as the <Shift>

 

[Jason210]

Almost. I had to put the <rotation> in the element parent, and the <shift> in child element that contains the <horizontalLine> object, which goes against intuition, but it was the one possibility I hadn't tried!

Thanks for help.

 

[rpmc]

The suggestion was to put it in only one Element.

<Element>
    <Visibility> ... </Visibility>
    <FloatPosition>x,y</FloatPosition>
    <HorizontalLine>
        <Bright> ... </Bright>
        <Axis>x,y</Axis>
        <Width> ... </Width>
        <LineWidth> ... </LineWidth>
        <LineColor> ... </LineColor>
    </HorizontalLine>
    <Rotation><Expression><Script> ... </Script></Expression></Rotation>
    <Shift><Scale>1,0</Scale><Expression><Script>(L:YourVariableX)</Script></Expression></Shift>
    <Shift><Scale>0,1</Scale><Expression><Script>(L:YourVariableY)</Script></Expression></Shift>
</Element>

 

[Jason210]

Thanks, without your help I wouldn't have solved this, but the only solution that worked for me was to put the rotation in the parent, and the shift in the child. I don't know why.

Anyway, I am approaching alpha stage with this gauge now, which is exciting. It's a map gauge which, when it opens, moves the centre to an offset random position so you don't know exactly where your aircraft is. If you tune into a VOR or NDB, it will draw a line across the map that intersects both the beacon and your aircraft. If you tune another VOR or NDB, it will draw its line so you can see where both lines intersect and know where you aircraft is. So the map simulates a navigator performing triangulation. I wanted to create something that I can use with older, pre-GPS aircraft. It will work with almost any aircraft but it was Just Flight's Boxcar that inspired it.