[Fluxus] Rotation Matrix issue

[evan.raskob]

It's great that you're going over this... that was on my list of things.
Also, adding a function to rotate vectors around an axis/angle would  
be great to add.  I really want to do this, but I'm fighting time  
before a 3-week trip, so we'll see what happens.

Also to add is the "cursor-finder" function (CTRL+b) to the editor +  
overtyping.  I need to commit this, will try to do it within the next  
few days!

Cheers
Evan




On 20 Mar 2009, at 20:48, Scott wrote:

> Well - since you asked (but this is truly a nit, since it's  
> consistent)
>
> The matrix derived from Quaternion rotation is backwards with respect
> to ones computed by the rotate(). One reason could be that the Matrix
> constructor that takes 16 values looks like it's col-major order. I
> think this is just in the quat-to-matrix code.
>
> But here's the test:
>
> (pmat (qtomatrix (qaxisangle (v3 0 1 0) 45)))
> 0.707   0.000   0.707   0.000
> 0.000   1.000   0.000   0.000
> -0.707   0.000   0.707   0.000
> 0.000   0.000   0.000   1.000
>> (pmat (mrotate 0 45 0))
> 0.707   0.000  -0.707   0.000
> 0.000   1.000   0.000   0.000
> 0.707   0.000   0.707   0.000
> 0.000   0.000   0.000   1.000
>> (pmat (qtomatrix (qaxisangle (v3 1 0 0) 45)))
> 1.000   0.000   0.000   0.000
> 0.000   0.707  -0.707   0.000
> 0.000   0.707   0.707   0.000
> 0.000   0.000   0.000   1.000
>> (pmat (mrotate 45 0 0))
> 1.000   0.000   0.000   0.000
> 0.000   0.707   0.707   0.000
> 0.000  -0.707   0.707   0.000
> 0.000   0.000   0.000   1.000
>> (pmat (qtomatrix (qaxisangle (v3 0 0 1) 45)))
> 0.707  -0.707   0.000   0.000
> 0.707   0.707   0.000   0.000
> 0.000   0.000   1.000   0.000
> 0.000   0.000   0.000   1.000
>> (pmat (mrotate 0 0 45))
> 0.707   0.707   0.000   0.000
> -0.707   0.707   0.000   0.000
> 0.000   0.000   1.000   0.000
> 0.000   0.000   0.000   1.000
>>
>
> On Fri, Mar 20, 2009 at 1:57 AM, Dave Griffiths <dave at pawfal.org>  
> wrote:
>> On Fri, 2009-03-20 at 08:48 +0000, Dave Griffiths wrote:
>>> On Fri, 2009-03-20 at 09:37 +0100, gabor papp wrote:
>>>>> It looks like the rotation matrix math in dada.h is  
>>>>> inconsistent; and
>>>>> the signs on the sins need to be flipped for the y-axis.
>>>> this seems to be right. nice catch. could you submit this as a  
>>>> bug please?
>>>
>>> A great bit of detective work - thanks Scott.
>>>
>>>>> I'm gonna make the change locally. This is an interesting one,  
>>>>> since
>>>>> people probably depend on the existing behavior -
>>>> i don't think this is a problem. this is the case with the planes  
>>>> and
>>>> the flipped texture bugs also.
>>>
>>> Yes. I think we need to set aside a week to fix all these things -
>>> probably just before we do a release, so we can all update our  
>>> scripts
>>> in one go.
>>>
>>
>> Shall I release 0.16 quite soon, end of next week-ish? Then we can  
>> get
>> all these niggly things fixed over the next few days, do a release  
>> and
>> then get the frame buffer pixels branch merged in afterwards for  
>> 0.17...
>>
>> So that means all we should commit is:
>>
>> * Plane orientation fixes
>> * Rotation fix
>> * Flipped texture coords fix
>>
>> Anything else?
>>
>> cheers,
>>
>> dave
>>
>>