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Thread: Function question...(resolved)...

  1. Jan 11th, 2003, 11:35 AM #1
    NoteMe
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    Function question...(resolved)...

    I'm making a car game, and I need to find a function for the acceleration of the car. I want the acceleration to be 0.2 when the speed is close to zero and the acceleration to be close to 0 when the speed is close to 10....anyone???



    The function should make a graf that looks like the picture. Something like an Ln function or something like that. ANyone know how to do that???
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    Last edited by NoteMe; Jan 11th, 2003 at 08:52 PM.
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  2. Jan 11th, 2003, 12:17 PM #2
    kedaman
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    something like this maybe
    a(v)=0.2-ln(v/10*(e-1)+1)*0.2
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  3. Jan 11th, 2003, 12:21 PM #3
    NoteMe
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    Originally posted by kedaman
    something like this maybe
    a(v)=0.2-ln(v/10*(e-1)+1)*0.2
    I tried your function, but it looks like the speed is close to zero the acceleration is more then 9. I wan it to be 0.2. Am I doing something wrong or, was you function fault????
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  4. Jan 11th, 2003, 12:36 PM #4
    NoteMe
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    I found it....

    Y(X)=0.1 - 0.1log X



    I was only looking at the ln function, but actually the LOG function was bether....
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  6. Jan 11th, 2003, 12:52 PM #5
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    No this is totaly wrong...forget this for a moment...I have to rethink my question....
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  7. Jan 11th, 2003, 12:56 PM #6
    NoteMe
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    Forget the whole thing. Thanks for trying to help me out. But the answer was something like:

    Acceleration = 0.23 - (0.1 * Log(Speed))

    so I'm not sure what I was doing...


    BTW: How do I use e(the natural number) and ln in VB code?????????
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  8. Jan 11th, 2003, 03:44 PM #7
    kedaman
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    base convertion a to b
    log x(b) =log a(x)/log a(b)

    in vb to get ln(x) you have log(x)/log(e)
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    writing software in C++ is like driving rivets into steel beam with a toothpick.
    writing haskell makes your life easier:
    reverse (p (6*9)) where p x|x==0=""|True=chr (48+z): p y where (y,z)=divMod x 13
    To throw away OOP for low level languages is myopia, to keep OOP is hyperopia. To throw away OOP for a high level language is insight.
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  9. Jan 11th, 2003, 03:49 PM #8
    NoteMe
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    Thanks, that was actuall something that I didn't remember from math...but thanks anyway...
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  11. Jan 11th, 2003, 08:51 PM #9
    alkatran
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    trig

    You could use a trigonometric function.

    'cos(0) = 1 cos(90) = 0 right??

    Accel = cos(currentspeed/maxspeed)*maxaccel

    im not sure if that woudl work as I haven't thought over it much/tv going in background

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  12. Jan 11th, 2003, 08:54 PM #10
    NoteMe
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    I don't think I can use Cos or Sin , because they only make perfect waves, if you see my pic at the top, it is a Ln/log graf.

    BTW I did, put a Resolved tag at the thead, because the game is working OK now. So you can consentrate on the TV instead...
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