Hi. Hans pointed me to this thread off list. Im definitely interested in porting some of my shaders to GEM, and making some easy to use abstractions that you can plop down in the GEM processing chain.
I actually emailed Chris Clepper off list earlier in the week regarding this. It looks like, however, that GEM and Jitter handle some things slightly differently, enough so where I may have to maintain more than one version of the shader code for both environments, or, maybe im just dont get whats going on. Either way im going to take a closer look at this friday. My goal is to have interchangeable shaders (Jitter uses an XML file to describe the parameters and declare what vertex and fragment program is loaded, but besides that 'jxs' file, id like the .vert and the .frag to be basically interchangeable). Id also include some basic abstractions for wrapping the shaders so you could just drop a
[v001.duotone] into the gem pipeline and get two tone processing for your textures. etc etc.
Once I get a basic set of shaders done that I am happy with, ill definitely be releasing them to the GEM community as well. Im also pretty new with this shader stuff, so expect some hiccups.
Right now the shaders I am working on are:
Mixers : A/B with blendmodes like overlay/hardlight etc
Mixers : A/B/C where C is mask based on luma or alpha
Effects:
Black and White
Texture clamping (makes cool lines in the middle of the image)
Color Separator (separate r g b planes in x/y)
Dent
Duotone
Exposure
Fader (fade to black/white, nice at the end of a processing chain)
Light Tunnel
Pinch
Posterize
Shred (interesting pattern/repetition creation)
Stretch
Threshold (high contrast colors)
Twirl
and some more
3D shaders
Vertex noise
Normal Map
Sin distortion
Because Jitter has a library of already created shaders, I may port some of those over so GEM folks have them as well, like saturation, contrast, brightness, and so on. The basics.
Peace :)
On Jun 26, 2007, at 3:09 PM, Cypod wrote:
What books or webpages are out there for learning how to write glsl
shaders, for use in 3D?
Has anyone read this one OpenGL(R) Shading Language (2nd Edition)
Are there any third party applications for writing glsl shaders that
can be easially ported over to PD?
I am hoping to learn more about programming by using PD, but it would also
be nice to crank out some good looking shaders in a timely manner
HI Cyrille and others.
I modified the abstraction to make opening the two files easier. It
uses file/parentfolder from the PdMtlAbstractions. (try it !! It
answers your question)
For the C programming and such, I just meant that it is nice if we can
tend to make Pd easier to use for people that are not that much used
to advanced programming. A good documentation and a nice structure
helps a lot...
a
Alexandre Quessy a écrit :
Eh Jack !
Very nice examples, yes. Cyrille, do you think that one should
understand C programming in order to use Pd? I don't.
i don't see your point here.
glsl programming is not very diferent from C. So, understanding C is
good for learning glsl.
but you don't nead glsl in order to use pd.
you just need glsl if you want to do very heavy pixel processing at
50fps / 1024x768 without using any CPU time by exemple.
Of course, its
low-level orientation makes it perfect for someone to learn lower
level stuff.
Anyways, I added an abstraction for shaders in the PdMtlAbstractions.
cut / paste the help file is (for me) easier to use, as i usually put
the shader in in the same directory as my patch, so i don't nead to provide
the full path for the shader. (and the patch could run on other computer
without changing all path).
is there a solution for an abstraction to know the directory of it's
parent patch?
cyrille
a
Yep, very interesting example !
You can "boost" Gem with glsl object.
Is there workshop in Paris about that Cyrille ?
I think, that it would be interesting to do.
Jack
Hans-Christoph Steiner a écrit :
On Jun 17, 2007, at 6:58 AM, cyrille henry wrote:
hello,
Kyle Klipowicz a écrit :
Ooop please send any elementary examples of these things.
i post a few very diferents shader and the pd patch to use them
here :
Wow, these are some nice examples, these should be included in the
"examples" section of Pd-extended.
well, i think i should clean up some code and check licence for the
shader
i did not write.
where should i put them in order to include them in pd-extended?
cyrille
.hc
I got
confused by the Gem docs (they don't explain OpenGL as
thoroughly as
the vanilla Pd-docs explain DSP).
Gem doc aim is to explain gem specific stuf. but in order to use
Gem,
you also need a good openGL book.
(you can find lot's of them)
cyrille
~Kyle
hello,
Alexandre Quessy a écrit :
Hi all !
The Toon.vert and Toon.frag shaders don't seem to work quite
well
here. I only get some kind of darker or lighter grey depending
on
the
value of the "Phong" variable I set it to have. I am using
Pd-extended
0.39-2 test 5 on Ubuntu Linux Intel. Gem is 0.91-cvs compiled
on Mar
16 2007. Should I generate something any better ?
this is exactly what the toon shader is aiming to do.
look at it's code to undersant why.
Anyone has an other GLSL shader to suggest to try it with ?
yes, google has a lot.
i have a few other exemple on my computer, tell me if you're
looking
for some specific stuf.
cyrille
Thanks !!
a
GEM is a bit easier to deal with for shaders since there is
no
need
to do
any specific wrapper. Any ARB_ vertex or fragment shader and
any
GLSL
shader you find on the web can work in GEM without
modification.
In some
cases you might need to change something in the shader text
to
deal
with
rectangle vs 2D textures.
On the cycling74 webpage there is an interesting article
about
writing
shaders for jitter:
is there a similar function available for GEM? Has anyone
had
experience
with doing this?
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