[PD] matrix operations with audio signals

Derek Holzer macumbista at gmail.com
Wed May 16 16:56:28 CEST 2018

On deeper inspection: [mtx_pack~] gives the same value to an entire row, 
so that is not what is needed.

A practical example, a 3D rotation matrix:

  1 0 0 0
0 cosR sinR 0
0 -sinR cosR 0
0 0 0 1

If [matrix~] is used to process the vectors which represent a cube, 
let's say, and I want the cos, sin, and -sin of the rotation angle R to 
be audio signals, how could I use [matrix~] to do that?


On 16/05/2018 17.43, Derek Holzer wrote:
> Dear list,
> I have been creating 2D and 3D oscilloscope graphics with audio signals 
> in Pure Data for some time now. I've started digging deeper into 3D math 
> and have found that the ability to do matrix operations at audio rate 
> would be extremely useful.
> Right now, the only option I can see is to use [matrix~] from IEMmatrix 
> lib, and to pack my other audio vectors using [mtx_pack~] in a subpatch 
> with [block~ 1] to get samplewise operations.
> Is this the best/only way to do this? Seems like the [block~] could make 
> it unnecessarily expensive.
> Thanks!
> Derek

derek holzer

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