Hey there
I'm trying to import a shader from ShaderToy in Pure data and I don't know what to do about "iChannel0". What can I do in my shader.frag ?
The use of "iChannel" (0, 1 and more) in ShaderToy is clear but I don't know how transform it for Pure Data. It appear everytime a shader use a noise animation and it's happend often.
An example of a shader with this function line 19 https://www.shadertoy.com/view/lslXRS

Any advice is appreciated. Thank you.

@Martin_LM Are you trying to use [glsl_fragment] in Pd......... from the Gem library.
If not, then you probably should.
Also.... https://forum.pdpatchrepo.info/topic/3835/blur-gemframebuffer
David.

@whale-av said:

https://forum.pdpatchrepo.info/topic/3835/blur-gemframebuffer

Yes I'm working with [glsl_vertex], [glsl_fragment] and [glsl_program].
In Gem exemples like "simple_texture.pd", they use [pix_image] in the pd patch (in the gemhead chaine, after [glsl_program]) to load a image.jpg.
They create a "uniform sampler2D MyTex;" in the .frag.
I don't understand the link between MyTex and [pix_image].

I'm trying to do the same in the shader (from shadertoy in my first post) by replacing "float noise( in vec2 x ){return texture(iChannel0, x*.01).x;}" by
"float noise( in vec2 x ){return texture2D(MyTex, x*.01).x;}",
after I had create my uniform sampler2D MyTex; of course.
I'm loading the same texture it's use in shadertoy but It does nothing.
There is not so many tutorial about glsl in Pure Data...

@Martin_LM Ok. I have never tried it, but someone else will get involved with your thread I am sure.

If you don't have it, then you should download this...... https://puredata.info/downloads/extended-view-toolkit.
It has, in its "ev-glsl" folder a help file and other files that use glsl. No tutorial, but you might well find some clues.
It could be as simple as the message ordering in Pd.
David.
PS.......****...... You will also find some dot.frag files that are used in their associated objects, and are recognisable when looking inside as the program to be run........ so you can see how they relate and communicate.

I'll try to find something in the toolkit, maybe I'll find the solution to do that.
Thx !