[PD] Drawing a sine function dynamically in Gem

[Roman Haefeli]

On Mit, 2013-04-03 at 11:59 +0200, Cyrille Henry wrote:
> hello,
> 
> you have lot's of solution to draw a sinus curve in Gem.

[...]

> you can also do like in openGL : using GEMglBegin, GEMglVextex (many
> of them thanks to an iterative loop), and GEMglEnd

I'm interested in understanding that approach. So far I was able to draw
a simple line:

[gemhead]
|
[GEMglBegin GL_LINES]
|
[GEMglVertex2d -2 -2]
|
[GEMglVertex2d 2 2]
|
[GEMglEnd]

But how are you creating an iterative loop out of this? I tried after
GEMglBegin:

[t a b a]
|    |   \
|    [20( \
|    |     \
|    [until]\
|    |       \
|    [gemlist ]
|    |          <- put the two [GEMglVertex2d] here.
|
[GEMglEnd]

However, this causes an error on every frame:
GL: invalid operation

What is the correct way to do this? 

Roman



> Le 02/04/2013 23:18, Alexandros Drymonitis a écrit :
> > I want to build this visual http://processing.org/learning/trig/ in Pd, but I want the sine curve to be drawn dynamically with every circle spin. It seems quite hard though.
> >
> > I don't know which object would be best. I tried either [curve] but the parameters are way too many and I'm not sure if precision is really possible. Then I tried [square 0.008] in combination with [repeat] but also doesn't work.
> > Anyone knows how to do this?
> >
> >
> > _______________________________________________
> > Pd-list at iem.at mailing list
> > UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
> >
> 
> _______________________________________________
> Pd-list at iem.at mailing list
> UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list