[Bf-python] AngleBetweenVecs found solution

[Gilbert, Joseph]

For some v1 * v1 operations the dot product was
1.000000000000000000000000000000001 which returns NAN when passed to the
acos() function. Hopefully the clamp solves things. Also, thx martin for
the implementation - was added.

-----Original Message-----
From: bf-python-bounces at projects.blender.org
[mailto:bf-python-bounces at projects.blender.org] On Behalf Of Martin
DeMello
Sent: Monday, October 10, 2005 12:12 AM
To: cbarton at metavr.com; Blender Foundation Python list
Subject: Re: [Bf-python] AngleBetweenVecs found solution

On 10/10/05, Campbell Barton <cbarton at metavr.com> wrote:
>     //normalize vectors
>     norm_a = (double)sqrt(test_v1);
>     norm_b = (double)sqrt(test_v2);
>     for(x = 0; x < size; x++) {
>         vec_a[x] /= norm_a;
>         vec_b[x] /= norm_b;
>     }
>     //dot product
>     for(x = 0; x < size; x++) {
>         dot += vec_a[x] * vec_b[x];
>     }

I think it would be slightly more accurate to take the dot product of
the unnormalised vectors, then divide by (norm_a * norm_b)

martin
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