[PD] gem live-video input

james tittle tigital at mac.com
Wed Dec 22 23:55:45 CET 2004

On Dec 22, 2004, at 1:20 PM, sara kolster wrote:
>>> I would like to combine the Gem-graphics [mostly 1px-lines] and a 
>>> live-input from a camera, preferably a firewire cam. Otherwise a 
>>> usb-wecam could be an option as well. The Gem-2-pdp bridge isn't 
>>> really an option, since this seems to be 'buggy' or too much for 
>>> CPU.

...you'll be happy to know that I've got an improved pdp2gem bridge 
working:  I'll commit it to cvs after a few more things are ironed 
out...one thing you might want to do with the current one is not use 
the [pix_rgba] object (as is shown in help-pdp2gem.pd):  it's 
incredibly slow, and not really necessary anymore...you can always use 
a blend message to get that alpha effect, anyway...

>> you can generate your 1-px lines as 2d planes and mapped your live 
>> video as texture.
> I now did it with the rectangle object and had a draw-line-message 
> connected to it. Is there another way of creating just 1px lines; i 
> don't know exactly what you mean with 2d-planes.

...don't know what you mean by "Gem-graphics [mostly 1 px-lines]" and 
live video?  Are you wanting to have each line (horiz. or vertical?) of 
the video as a seperate line?  Or do you want to just draw lines over a 
video?  If the latter, just map the video to a rectangle, then use 
[curve] or [curve3d] or whatever to draw in front:  see their help 
files for more info...

> Another issue i have is that i cannot move my gemwindow, how do I set 
> the properties for that window? A posdim message, doesn't work. [I 
> couldn't find the helpfile for the gemwin in the Gem-documentation.]

...uh, look in "Gem/help/gemwin.pd"...there is also 
"Gem/examples/02.advanced/15.GemWin.pd"...but, I don't think either of 
these address the "can't move the gemwindow" problem (outside of 
manually sending offset messages)...there is a trick to get it to work 
on osx:  hold down the command button when you click on the window's 
title bar, and you'll be able to drag it around (also works for giving 
[gemmouse] input)...

...you'll of course notice immediately that the window never comes to 
the front, and it's kinda weird dragging a window behind other windows, 
but it works for now...this is due to how pd is built on osx:  because 
it is run as a command line app that then calls wish shell to do it's 
gui...osx won't let command line apps have front position in the window 
manager without some secret handshake, and I still haven't figured out 
what that is  :-(


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