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Steve Johnson

Floating Point 64

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Hi Peter,  my Lua programming has hit a wall.  I have installed a home made GEN AMP stepper instrument which operates from an offset. I can easily set it up to work from an FSX offset 2888. However I am using an add on for the aircraft which gives a much more accurate reading and simulates much more of the electrical system. I know how to read from the add on programs local variables in Lua and to write to a custom offset. I can read from from the add on program and write it to custom offset using ipc.writeDBL and display it to the screen through FSUIPC.  i.e. 30.0000. The problem I have is that I have used all of the custom offset range right through to 66FF and I only have one offset available. The value range represented by the internal variable I am reading from is only 0 - 30, but it is stored in a floating point 64 type variable which uses 8 bytes or 8 offsets.  My question is, is there a way to extract the value and convert it to one byte with the value been within that range (no need for fractions)?  My plan B was to manually convert by writing


If myVariable = 30.0000 Then

         myVariable = 30

ipc.writeUB (0x66D4,myVariable)  


but this did not work :(


Any help would be greatly appreciated.

Regards Steve




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Hello Steve

You could use math.floor(x)

Returns the largest integer smaller than or equal to x.

Or a function

function toint(n)
    local s = tostring(n)
    local i, j = s:find('%.')
    if i then
        return tonumber(s:sub(1, i-1))
        return n


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Hi. When I used math.floor(30.0000) as a test, it returned 30. As soon I replaced the number with my variable it would only return to a double floating point 64 type.  Your function worked perfectly. 

Thank you very much for you help.


Regards Steve

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