[p5.js 2.0+ Bug Report]: Fill interpolation in TRIANGLE_FAN broke between 2.1.2 and 2.2.0

[davepagurek]

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

2.2.0+

Web browser and version

Firefox

Operating system

MacOS

Steps to reproduce this

Steps:

1. Create a WebGL canvas
2. Create a triangle fan with separate fills in the center and radial vertices

Here's what we get on p5 2.2.0+:

Here's what 2.1.2 looked like:

Snippet:

function setup() {
  createCanvas(400, 400, WEBGL);
  beginShape(TRIANGLE_FAN)
  fill(0)
  vertex(0, 0)
  fill(255)
  let n = 10
  let r = 100
  for (let i = 0; i <= n; i++) {
    const angle = i/n * TWO_PI
    vertex(r*cos(angle), r*sin(angle))
  }
  endShape()
}

Live: https://editor.p5js.org/davepagurek/sketches/QEYON0ddE