Thanks
@ThEmu, I was hoping you would join the discussion
These all boil down to one of
1) Use a randomly selected image of some sort as your source of randomness
2) Use the least significant bits of the elapsed time as your source of randomness. The variability of a scene's startup times and timing jitter when running stop this being predictable.
In the digital clock scene I posted a few days ago http://bit.ly/3XL6O5P I already used 1) above. Having first set up 100 shades of grey that could be picked at random. I was very pleased with the result but of course this seems to have used up the one and only texture slot.
@Everthang mentioned that he uses framebuffers to get two separate textures into the shader e.g In FG842 so what I would like to understand how to do next... if possible is to convert that input which appears like this:
uniform sampler2D texture0;
uniform sampler2D texture1;
varying vec4 gl_TexCoord[];
...
highp vec4 zero = texture2D(texture0,vTexCoord.xy); // input zero 0
highp vec4 one = texture2D(texture1, vTexCoord.xy); // input one 1
... and further process that back into a format that a shadertoy shader would understand to be multiple textures that could then be used as normal.