[PD] GEM: Change buffer without destroying?

Ben Bogart - FMPM/F1999 bbogart at acs.ryerson.ca
Sat May 4 21:48:18 CEST 2002

Hi David,

As far as I know you have to destroy the gemwin in order to change the 
buffer mode. If you put your gemwin in the corner and have a 
background that matches and no border in your window then you can 
destroy the window without it being visible.

In terms of gemPixDataSimple... buffer 1 is single buffer mode which 
does not redraw the screen for each frame. This means that the last 
frame rendered stays on the screen for the second frame. In the case 
of single buffering you must tell all the gemheads when to render 
(with a bang). This example patch uses single buffering because there 
is just one sphere that is translated each time it is told to render, 
so that each position the sphere was told to move to remains on screen 
(in the buffer)

Hope that helps.

On Sat, 4 May 2002, David Sabine wrote:

> Hello,
> I'm using GEM to render a number of different visual effects and ONE of those structures requires a gemwin buffer value of "1" while all others work best at "2".
> These structures don't need to render simoultaneously - but it would be nice.
> However, when I try to change the buffer size by sending the value to gemwin, the GEM window starts acting erratically.  Hence, I'm guessing that the buffer size can only be changed after destroying the gem window before creating a new one (am i right to assume this?)
> So the question is: How can I change the buffer size of the gem window without destroying the window?
> sub-question: The gemlist that I'm having difficulty with is similar to gemPixDataSimple.pd from the GEM examples.  Why does that type of structure require "buffer 1"?  How can that example patch be modified to work with "buffer 2"?
> Thanks...
> Dave S

B. Bogart

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