Warp <war### [at] tagpovrayorg> wrote:
>   What obstacle?
>
>   The question was: Is it possible to calculate the tangent of a spline with
> absolute accuracy? The answer is obviously: Yes, it's possible.
>
>   What does the macro you are talking about have anything to do with this?

....

>   The original poster asked if it's possible to calculate the direction of
> the spline with complete accuracy. You said that it's impossible. That's
> clearly not true.

*Sigh*

RTFOP, man. If you did, then please do so again.

The OP was all about "fixing" that *macro*.

I told him it is fundamentally impossible to "fix", and explained why that is
so.


>   So what? What is it in SDL that prevents you from evaluating a function?
....
>   Maybe you should go back to school to learn how to calculate derivatives
> because you clearly don't seem to grasp the concept.

This is getting ridiculous. Read my posts. Again if you like. Until you have
grasped it.

Or leave it if you're too lazy or stoned or whatever.

I'll try just once more again:


Calculus is not the problem. Getting the type of function and parameters out of
POV-Ray and into SDL is.

There *IS* an interface to get f[P](x) out of POV-Ray into SDL, where f is the
spline function and P are the parameters (i.e. control points).

There is *NOT* an interface to get an exact f'[P](x) out of POV-Ray into SDL. (I
don't believe the f' are even coded into POV-Ray.)

There is *NOT* an interface to get the generic formula for f out of POV-Ray into
SDL (i.e. you don't know if f is a linear spline, cubic spline, akima spline or
what-have-you).

There is *NOT* an interface to get the actual values of P out of POV-Ray.

=> There is *NOT* an interface to get anything out of POV-Ray to compute f'[P],
hence there is *NOT* a way to compute an exact value of f'[P](x).


>   You have failed completely to explain the problem. You have just rambled
> about how something is impossible in SDL without giving any actual example.

In case you don't realize, knowing that a feat is fundamentally impossible *is*
a valuable contribution to a problem, because it makes clear that it's not
worth trying.

All you contributed doesn't help the OP in any way. All your claiming that there
*is* a way without showing *how* is only suited to potentially confuse.

So, tell us, how can the macro be fixed - or please STFU.


'Nuff said, or I'll get real personal. Get out of that "I know better" mode
you're currently in, Warp.

Post a reply to this message