Real to Integer Conversion Issues

[AoW_Hun7312]

When I convert my real to integer, it doesn't convert correctly. The value of the real is 315.00, and the value of the integer ends up being 314. I found a way to bypass this by using R2S and S2I in conjunction, but there has to be a simpler way. Can anyone help?

 

[Darthfett]

Can you post your code?

 

[AoW_Hun7312]

    private function Check takes nothing returns nothing
        local unit u = GetEnumUnit()
        local real current = GetUnitMoveSpeed(u)
        if (current != GetUnitDefaultMoveSpeed(u)) then
            call SetHeroAgi(u, S2I(R2S(current)), true)
        endif
        set u = null
    endfunction

If I remove the S2I call, the value is 314; otherwise, it's 315.

 

[Ashlebede]

Maybe it's not floored correctly... maybe doing [ljass]R2I(current+.1)[/ljass] would work. u_u

 

[uberfoop]

Real operations in general in wc3 have idiotic results that are often off by extremely small amounts. It's possible that the R2I things that the real is like, slightly below 315. This wouldn't happen with S2I(R2S( because R2S rounds out to only a few decimal places, so the S2I conversion would see 315.000 or whatever instead of 314.999999999blahblahblah what the game thinks it is.

Or something. I think.


But yeah, either don't worry about it or go with Ashlebede's plan of adding a small value. You could probably even get away with making it a very small value, like .001.

 

[tooltiperror]

Oh yes, the crappy world of WC3 numbers and mathematics. Horribly done, hopefully the next decent blizzard WC game has better math.

If you really wanted to, you could go with your [LJASS]S2I(R2S(somereal))[/LJASS] approach and make a function that JASSHelper will automatically inline, which is probably the easiest thing to do.

.
 function Real2Integer takes real r returns integer
     return S2I(R2S(r))
 endfunction

Of course, I'm pretty sure that double-converting works to, and I think that parsing a string in C++ is slower than converting integers and floats, so it may be quicker to 'double-convert' like this, although I'm not even sure if it works, although I think I remember doing this in a minigame map I made to get rid of those nasty .000's before they even appeared or something.

.
 function Real2Integer takes real r returns integer
     return R2I(I2R(R2I(r)))
 endfunction

If that does work, it is probably the best thing to do, and it inlines thanks to Vexorian's genius.

 

[Bribe]

R2I(I2R(R2I(r)))

That will produce the same thing as

R2I(r)

They will never produce different results.

 

[saw792]

Just to clear something up... this isn't a wc3 maths problem, this is a floating point problem related to how floating point numbers are represented internally by the computer. You will find the same problem in most programming languages, which is why you should never compare reals for equality.

 

[uberfoop]

Just to clear something up... this isn't a wc3 maths problem, this is a floating point problem related to how floating point numbers are represented internally by the computer. You will find the same problem in most programming languages, which is why you should never compare reals for equality.

Yeah, it happens in any floating point system. However, I still blame Blizzard for all the madness. Casual mappers + floating point arithmatic + no warning signs = WTF!?

 

[Bribe]

Not only, but so many parameters in this game depend on floating-points because of coordinates, facing angles, damage, HP, MP, fog values...

You would think HP and MP would be integer-based, based on what you see in-game with it.