[p5.js 2.0+ Bug Report]: Should not emit FES warnings on GLSL keywords outside of p5.strands

[ksen0]

Most appropriate sub-area of p5.js?

• Accessibility
• Color
• Core/Environment/Rendering
• Data
• DOM
• Events
• Image
• IO
• Math
• Typography
• Utilities
• WebGL
• WebGPU
• p5.strands
• Build process
• Unit testing
• Internationalization
• Friendly errors
• Other (specify if possible)

p5.js version

2.3.1

Web browser and version

any

Operating system

any

Steps to reproduce this

This issue can be observed in processing/p5.js-website#1522 where the use of length in p5.js sketch code results in FES warnings that actually can be safely ignored. These warnings apply to p5.strands code, which is pseudo-javascript: ie, it is transpiled to glsl. So it has a bit of a different scope than a p5.js function.

For example, the below code should trigger the warning:

let video;
let displaceColors;

function setup() {
  createCanvas(700, 400, WEBGL);
  displaceColors = buildFilterShader(displaceColorsCallback);
  describe(
    'A video of a city crosswalk, with colors getting more offset the further from the center they are'
  );
}

function displaceColorsCallback() { 
  // everything inside this function is p5.strands code: it is javascript-like, but it is transpiled into a glsl shader. Therefore, GLSL functions/keywords including `length` should result in FES warning not to redeclare, even though they can be redeclared OUTSIDE of this p5.strands builder.
  function zoom(coord, amount) {
    return (coord - 0.5) / amount + 0.5;
  }
  filterColor.begin();
  const length = 0; // this doesn't appear to have any effect but should result in a warning
  const uv = filterColor.texCoord;
  const r = getTexture(filterColor.canvasContent, uv).r;
  const g = getTexture(filterColor.canvasContent, zoom(uv, 1.05)).g;
  const b = getTexture(filterColor.canvasContent, zoom(uv, 1.1)).b;
  const a = getTexture(filterColor.canvasContent, uv).a;
  filterColor.set([r, g, b, a]);
  filterColor.end();
}

function draw() {
  background(255);

  circle(mouseX-width/2, mouseY-height/2, 200)
  filter(displaceColors);
}

But the code in this example should NOT have FES messages related to length because that's used outside of p5.strands code.

[ksen0]

Hi @kaissy-a here's that length issue!
(Claimed in a prior discussion, see linked issue in body)