[PD] freehand drawing in Gem

ben at ekran.org ben at ekran.org
Wed Oct 8 23:40:09 CEST 2003

Hey Chris,

On the topic of vertex arrays and how to deal with all that data... I just
had an idea for a vertex array controller. Basically its a grid of values,
or pixels. (This could be implimented in tcl/tk, or in openGL, but GLUT
sounds like a problem). The creation arguments are the width and height of
the grid, perhaps also how big it apears in the patch, or whatever. You
can change the values of the pixels by clicking and dragging up and down
(just like a number box) or perhaps you could draw one pixel at at time.
There would also be objects to load image-files into these grids, which
the can be controlling the vertex array. It would be very nice to use pix_
data in these controllers, and very interesting if you could load live
video, QTs into them. These arrays would be storing 3D data, so you would
have to use multiple layers/channels to get really complex stuff going.

The seed idea I guess is to control a vertex array with the values in a
small (maybe) pix_ buffer. then you can control the vertex array via pix_
objects, and maybe also do some hand control as well.... (via the vertex
array controller object) Of course we would need a fast gui... Maybe the
controller would have to be openGL itself.. (but then what about the mouse
positions? SDL gives GL wrapping and mouse position data and it is

Anyhow there is the creative moment of the day.


> It should be possible with the vertex_array stuff.  I just saw a demo of
> Luxology's forthcoming 'modo' and it converted free hand drawing into
> tubes. While GEM might not do anything that fancy very soon, a similar
> idea could be made into an object.  Each new point input into the object
> would be a new vertex and jumping between points would result in more
> minear structures.  It would be easy to use this with something like
> Yves' grid object.  I'm not sure about getting position info from the
> gemwin and having it consistant across platforms without using GLUT for
> everything.
> cgc
> Quoting ben at ekran.org:
>> Hmmm, sounds good Yves!
>> I wonder if anyone has done something similar for Gem? I would like to
>> draw masks over video in realtime. So this pen tool should include an
>> algo
>> to fill in the object being drawn...
>> Any thoughts?
>> Thanks
>> Ben
>> >
>> > hi,
>> >
>> > 0.12.8
>> >  added pdp_pen : a free hand drawing object
>> >  ( on request from patrick )
>> >
>> > cheers,
>> > sevy
>> >
>> >
>> >
>> >
>> >
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