Passing multi-dimentional arrays in PD? WAS: Re: Re: [GEM-dev] curve3d acts very very odd with lots of control points OSX+Linux)
ben at ekran.org
Sun Jul 24 23:27:46 CEST 2005
Good to hear. Is there an example patch that shows how to offset each
vertex by 0.1 units out along its normal?
Just as a point of discussion one of the arguments for numarray is that
it is more efficient with arrays larger than 20,000 elements. I have a
patch that simply subtracts 0.1 units from the Z access of a particular
control point. What has amazed me is that I needed no interpolation
because the numarray code ran fast enough to create smooth movement.
Indeed these are issues worth discussing. Also between iemmatrix,
gridflow and VASP (numarray/python) seems arrays are "IN". ;)
Oh and here is some numarray info:
Thanks for the clarification Chris, I'll have to do update of my vertex
chris clepper wrote:
> The vertex_array objects do allow for a single point (vertex, color,
> texcoord, normal) to be modified as well as a range. It's very easy to
> do this by offsetting the pointer and counting from there. This does
> not allow for selecting two non-contiguous ranges or do anything more
> programmatic like skip every third point. You could use [repeat] to
> iterate through the same array each render pass but that is probably not
> very efficient.
> Once you start loading models of any complexity into vertex_array chains
> it becomes apparent that these objects need to be very efficient. A
> model with 10,000 vertices has a 40k vertex array, a 40k color array, a
> 30k normal array and a 20k texcoord array. That is 130,000 floats or
> 520,000 bytes per frame to process. Multiply by 30 or 60 frames per
> second and that is moving a lot of data.
> That example also points out the trouble with giving a user some sort of
> representation of all of that data. I don't think any of Pd's objects
> or external libraries are designed to deal with structures of this size.
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