[p5.strands] Implementing a noise function in strands

[lukeplowden]

Increasing access

This enhancement is part of the effort to integrate p5.strands more integrated into the core library (see parent issue #7849)

Most appropriate sub-area of p5.js?

• Accessibility
• Color
• Core/Environment/Rendering
• Data
• DOM
• Events
• Image
• IO
• Math
• Typography
• Utilities
• WebGL
• Build process
• Unit testing
• Internationalization
• Friendly errors
• Other (specify if possible)

Feature enhancement details

A noise implementation in p5.strands would allow for a lot of interesting effects using p5.strands, for animating objects and rendering materials. This could be a GLSL implementation of simplex noise, or another algorithm.

In order to get this working, something similar to getTexture could be a good approach. That function is defined here in strands and also here in GLSL. This would mean making a new function call node in strands, and writing the GLSL function somewhere to be included in shaders. I would be inclined to make this a new GLSL file, since we might add more functions to it in the future.

The implementation can be different than the core library version of noise, with potential to add a noiseMode(GPU || CPU) in the future.

[davepagurek]

Some notes for working on this:

• Some noise approaches use a big table of noise values, but we probably don't want to use that for now if we're going to be adding this helper function to all shaders
  • Potentially in the future, we can conditionally add it only if a shader makes use of it, but if our implementation is small, it's OK not doing that yet
• If we're borrowing a GLSL noise implementation from the internet, that could be OK but we should be explicit about it and discuss what its software license is
• A lot of references to noise functions that you see only implement base noise. p5's noise() uses fractal noise, which looks something like this:

  for (int i = 0; i < 3; i++) {
    result += pow(2.0, -float(i)) * baseNoise(input * pow(2.0, float(i)));
  }

  In p5 the factors are controlled by noiseDetail, but it's also OK to just hardcode the default values for now and connect it to noiseDetail in a later update.

[LalitNarayanYadav]

Hi @davepagurek! Just leaving a comment here so you can assign the issue to me. Looking forward to working on this one too 🙂

[davepagurek]

Thanks! I'll assign it to you.