[PD-dev] Functional Programming & C code generation

Claude Heiland-Allen claude at mathr.co.uk
Fri May 17 12:47:21 CEST 2013

On 16/05/13 16:32, Tom Schouten wrote:
> What I want to do is to get the image processing part of PDP to run on
> the GPU.
> Target platforms: desktop, Android, iOS, something like raspberry pi, ...
> Currently probably Android as first attempt.

OpenGL ES2 is probably the best thing to target first for phones and rpi:


The pdf spec seems to be quite readable.

I think ES2 is vaguely the intersection of OpenGL 2 and OpenGL 3, with
some parts removed and other parts adapted to embedded systems.

There's an ARB_ES2_compatibility extension for full OpenGL, so it should
be simpler to port from GLES to GL than the other way around.  Plus Mesa
>= 8 apparently supports GLES.

> Also, PDP is 16 bit integer pixel depth.

16bit per channel or per pixel?

> Is that something that can be done easily these days?

In OpenGL, yes - but OpenGL ES 2 only goes up to 8bit per channel (apart
from Depth which goes up to 16bit I think) and there are some packed
formats with fewer bits per channel (pages 63 and following in the spec
pdf).  There are probably extensions to GLES that support more stuff.
Also computation is specified as "floating point with accuracy to around
1 part in 10^5", with precision modifiers for less/more
accuracy/speed...  Desktop OpenGL also uses mainly floating point for
computation, with more storage formats (eg float textures).


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