There was a question how to plot a mandelbub on the forum, I found a shadertoy sketch and converted it to run with JRubyArt, here is the sketch run from the Atom editor:-
Frame rate (30 fps) was essentially the same when run as processing sketch from processing4 ide.
Thank you!
From what I see here you load a pre-calculated shader and display it.
Without calculating the thing
Thank you very much!
I am a little confused about that.
Doesnāt Processing use OpenGL as the basis for its P2D and P3D renderers?
In the shader tutorial is explained for example which steps are taken to render a Pshape as shader.
The actual gsls file I see as a code running at real time.
How must I understand pre-calculated?
As @Chrisir being confused! 
It may not be useful to think of this shader with respect to PShape though?! From the Processing side this is just drawing a full screen quad (rectangle), like all the ShaderToy shaders. As you say, everything is GLSL code running at real-time - quite literally in the sense that every pixel in every frame of the animation is calculated mathematically based on its x,y coordinates and the time in seconds. If you change how you update the uniform for time every frame, you change the animation rate / run it backwards / make it stationary.
I must admit the logic involved in the āreversalā of the calculation - from plotting a shape to working backwards from the pixel coordinates - scrambles my brain a bit! 
