hello,

the repeat/gemlist trick is very fast. it can be used to render lot's more 
point in real time.
(try pmpd example 57 : 2000 points are rendered at 50 fps on my computer with 
no problem)

i suspect that the bottleneck is the list parsing.
one trick to speed this is to put the list in a table, and use tabread to 
access the data.
(i did not have a look a the patch, so i may be wrong).

cheers
c


Le 02/09/2012 18:01, Max a écrit :
hi list, william,

this is a Gem recursion and glsl question.
in the example patches for timbreID there is an interesting patch where the 
grains of a sample can be seen as a point cloud according to their parameters. 
this is done by parsing a long list for each point throuch a recursive gem 
chain using [zexy/repeat] it works very well up to 40 points (or a sample of up 
to 10 seconds). However, when you try to do this with a sample of 4.5 minutes 
it doesn't work any more because the list parsing and gemlist repeating for 
each and every point (then about 900) at framerates of 10 fps is to heavy on 
the CPU.
William resolves this by rendering it once and taking a snapshot of the scene. 
that works nicely, but is not an option for my work, as i want to see the 3d space 
and navigate in it real-time. I was wondering if this could be done more 
efficiently and where to start. I think the points should be rendered in a glsl 
environment and the list of every points position should be static (in a matrice?) 
and not called and parsed by [list] objects at a rate of >9000 times per 
second. Unfortunately the geometry shader example doesn't work here, i was hoping 
to get some clues from there.

william has a tiny image of a point cloud on his page:
http://williambrent.conflations.com/pages/research.html#timbreID

max
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