[PD-dev] canvas class polymorphism

[Charles Henry]

Hi, hc

Let me explain a little further here.  The end goal is to have an external
library that allows one to create externals that use memory on GPUs.  Big
idea here is that once you've got a system for handling the memory
allocation and dsp sorting in *exactly* the same way as Pd, then you can
write externals for CUDA or CL in a way that's consistent with existing
externals.

With Pd handling the signal memory allocation inside of d_ugen.c and called
from canvas_dodsp, I wanted for my external library to have its own canvas
class and different methods for handling the memory allocation differently.
In fact, I think of that as being the key class to create the library.

I worked through it for a while, and I think it's just plain impossible to
have another canvas class in an external library, unless there's something
good I don't understand.  And I really want to understand :)

So, since then, I've been thinking that I'd have to modify the pd-vanilla
source code.  I've got something that loads a CUDA device and gets me to run
code during canvas_new, canvas_free, and canvas_dsp.  I'm still trying to
organize around the idea of having an external library to load and make as
few changes directly in the vanilla source code.

Chuck

On Wed, Mar 23, 2011 at 1:51 PM, Hans-Christoph Steiner <hans at at.or.at>wrote:

>
> What's the end goal here? You want an object that acts like a
> t_canvas/t_glist?
>
> .hc
>
>
> On Mar 13, 2011, at 3:31 PM, Charles Henry wrote:
>
>  I've been working through my CUDA Pd project, and I ran into the problem
>> of making externals that copy the canvas class.
>>
>> My first idea was that I wanted a completely separate class with different
>> methods using glist.  Calls from Pd looking for t_canvas work just fine, but
>> functions like pd_findbyclass that look for canvas_class fail.  I started
>> mucking around in the pd src, and I think it's just too difficult and would
>> make onerous changes that I don't like.
>>
>> Is there something I'm not getting about canvas classes and externals?
>>
>> My second approach to creating an external library is to modify glist by
>> adding an "unsigned int gl_hascuda" variable.  I'd still prefer solutions
>> that make use of entirely external libraries over modifying src, but this
>> small change gets me half the way there.  Then, I just need to write the
>> creator functions and the class works.
>>
>> Chuck
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>
>
>
>
>
>
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