[p5.js 2.0 Beta Bug Report]: vertexProperty() breaks if drawing with strokes

[davepagurek]

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)

p5.js version

2.0 beta 1

Web browser and version

Firefox

Operating system

MacOS

Steps to reproduce this

When drawing strokes, we don't duplicate custom vertex properties to the different parts of strokes. When you try to draw strokes with per-vertex properties and use a shader that reads it, you get this warning in the browser console (not the p5 editor console though! open the browser one):

WebGL warning: drawArraysInstanced: Vertex fetch requires 51780, but attribs only supply 11526.

let snake
let snakeShader

function setup() {
  createCanvas(400, 400, WEBGL);
  
  snakeShader = baseMaterialShader().modify({
    vertexDeclarations: 'in float len;'
  })
  
  const pts = []
  for (let i = 0; i < 50; i++) {
      pts.push(createVector(random(width), random(height)))
  }
  
 snake = buildGeometry(() => {
    noFill()
    beginShape()
    for (const [i, { x, y }] of pts.entries()) {
        vertexProperty('len', [i/(pts.length-1)])
        splineVertex(x, y)
    }
    endShape()
  })
}

function draw() {
  clear()
  strokeShader(snakeShader)
  model(snake)
}

Live: https://editor.p5js.org/davepagurek/sketches/KwUdPojKW