Hm... yes, I know in particular how to setup a shader through the Editor. I use spatial shaders, so through the Editor I'm able to add a MeshInstance, a Mesh, a ShaderMaterial, and then finally a Shader to it. This much is clear.
My question has to do with having precise control over the Shader execution. Say that I setup the above through GDScript, and that I'm able to set a uniform input to the Shader. How then do I tell the code to say only run the Shader program once? Such that I set my input, I run the Shader only once, then I am able to read the output (in form of the texture). How does one do so?