[PD] Free rotation in GEM

[cyrille henry]

ok.
i think i undersand.

there is an other possibility based on the gemlist_info object that get curent transformation matrix and convert it to rotation / translation ...


so, what i think is the most simple is : 

	gemhead
	|
	rotateXYZ (for the drag rotation, should be (0 0 0) when you don't drag)
	|
	rotateXYZ (for a feedback loop thanks to the rotation given by by the last object on the chain)
	|
	object primitive
	|
gemlist 		(the gemlist should be banged only at the end of the drag)
|
gemlist_info (get curent rotation at the end of the drag, and send it to the 2nd rotate)
 

you can save few cpu using gemlist_matrix and GEMglMultMatrix.

this is a bit like the algorythm you describ, execpt that everything is computed on the GPU (it is more the Gem way to do).

cyrille

PSPunch a écrit :
> Hi,
> 
> 
> My primary goal is to place an object you can rotate by dragging the mouse.
> 
> 
> Basically, whenever the mouse is clicked to start drag, I want to rotate 
> the object on the X & Y axises. Up to this point is no problem, but I 
> want the rotation to begin assuming the direction of the viewer being 
> the bases of the axis.
> 
> Using one [rotate] object, I can get the object to rotate in the 
> behavior I expect only on the first drag.
> 
> Ideally, each time the mouse button is released, the base (fundus? 
> basal?) of the rotation vector should be updated... I think.
> 
> By chaining [rotate] objects, I can use one to rotate the rotation axis 
> and another to rotate the object from that point.
> However, I have not found a method of summing multiple drag actions.
> 
> 
> Although I may be wrong, I think what I need to do is,
> 
> 
> 1. Prepare two rotation axises
>     I. Angle of the axis
>     II.Angle of the current drag session
> 
> 2. When the mouse button is clicked, rotate object to
>     angles I + II
> 
> 3. When the mouse button is released, sum I + II and wait for
>     a new click.
> 
> 
> And again, although I may be wrong, my current understanding is that 
> step 3 will require multiplying the X-Y-Z angles converted to 
> quaternion, or some other method which will rotate the Z axis at some 
> point by summing rotations based only on the X&Y axises.
> 
> 
> Using procedures completely different from the one mentioned abouve, I 
> was able to achieve the expected behavior based on [accumrotate] but I 
> found no simple way of managing the current angle.
> 
> Unfortunately I have torn down the patch. If it would clarify anything, 
> I will try to put together another one later today.
> 
> 
> Thanks for replies.
> --
> David Shimamoto
> 
> 
>> Indeed,
>>
>> Seems to me all the matrix discussion does not get to the heart of the
>> question.
>>
>> So, Pspunch, what are you really trying to do?
>>
>> I agree with cyrille that It's very likely the normal rotation objects
>> will do what you want it to.
>>
>> If you are just wanting to rotate many times, using huge numbers then
>> tricks like: wrap 0 359 work well...
>>
>> ..b
>>
>> cyrille henry wrote:
>>> hello
>>>
>>> sorry if i misunderstand.
>>> rotateXYZ will rotate in X direction, then in Y, finally in Z.
>>> if you wish to rotate in Z, then in X, you just need 2 rotate objects:
>>> the 1st for the rotation in Z, then an other for the rotation in X.
>>>
>>> anyway, there is no matrix manipulation that i was not able to do with rotate/rotateXYZ/translateXYZ/scaleXYZ/shearXY..
>>> so i'm quite sure you don't need anything else than this standard objects for simple matrix rotation.
>>>
>>> so i think you need 1 [rotate] to rotate the vector axis of the object, then a accumrotate.
>>> if i misunderstood, could you please describe your problem better.
>>>
>>> I think you can also use GEMgl objects to multiply the matrix with a custom one, but it's to much complex for what you need.
>>>
>>> cyrille
>>>
>>>
>>>
>>> PSPunch a écrit :
>>>> Hi Mathieu,
>>>>
>>>>
>>>> I have not looked into GridFlow much, but I had the impression that its 
>>>> main concept was to add matrix manipulation features to Pd, all of its 
>>>> visual capabilities being just one of the many results of data you can 
>>>> manipulate with matrix. (or is the egg first?)
>>>>
>>>>
>>>> Anyway, understanding its marvelous potentials, I have lately been stuck 
>>>> with Windows platforms. At least I got your point that utilizing 
>>>> GridFlow only for crunching numbers may work but not so efficient.
>>>>
>>>>
>>>>
>>>> What I am trying to do is rotate the vector axis of the object before 
>>>> applying [rotation]. This also calls for a method of summing the 
>>>> rotations when applying multiple times (and my current understanding is 
>>>> that this can only be done by multiplying the quaternion on each rotation)
>>>>
>>>> If there is no solution at the moment, perhaps Gem could use a few extra 
>>>> objects to ease advanced rotations?
>>>>
>>>> I feel like I am complaining about lack of features without pointing out 
>>>> what exactly is missing, when I should be blaming my lack of math skills.
>>>>
>>>> hmmm..
>>>>
>>>> --
>>>> David Shimamoto
>>>>
>>>>
>>>>
>>>>> On Wed, 16 Jul 2008, PSPunch wrote:
>>>>>
>>>>>> Trying to achieve free rotation *without* using [accumrotate], I have
>>>>>> come across concepts such as multiplying matrixs and converting a matrix
>>>>>> to "quarternion"
>>>>>> How do you implement precise control of rotation matrixs?
>>>>>> Is this exactly what people use GridFlow for?
>>>>> If you tried GridFlow's bundled examples you'd see what I use GridFlow 
>>>>> for. I suppose that I could add some other people's examples in the 
>>>>> package, if they sent it to me for that purpose. There is already one 
>>>>> patch by Roman Häfeli in GridFlow's examples though.
>>>>>
>>>>> GridFlow does not support quaternions. I bet it's possible to add 
>>>>> support for it using abstractions, but it wouldn't be fast. But I'm 
>>>>> willing to add it to the core... there's already a complex-number 
>>>>> section in number.c, why not quaternion product? It would be called [# 
>>>>> H.*] where H stands for Hamilton (in math the letter Q is already 
>>>>> reserved for rationals, so I'd use H even though the concept of rational 
>>>>> reasonably couldn't appear in that particular place).
>>>>>
>>>>>  _ _ __ ___ _____ ________ _____________ _____________________ ...
>>>>> | Mathieu Bouchard - tél:+1.514.383.3801, Montréal, Québec
>>>> _______________________________________________
>>>> Pd-list at iem.at mailing list
>>>> UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
>>>>
>>>>
>>> _______________________________________________
>>> Pd-list at iem.at mailing list
>>> UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
>>>
>>
> 
> 
> _______________________________________________
> Pd-list at iem.at mailing list
> UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
> 
>