The p5.erase() function does not work as expected for WEBGL

[gmaster350]

Most appropriate sub-area of p5.js?

• Color
• WebGL

Details about the bug:

The p5.erase() function does not work as expected for WEBGL;
it will turn part of the canvas white, but not transparent.

• p5.js version: 1.4.0 ( current, as of posting )
• Chrome, Firefox, Edge ( all current versions as of posting )
• Windows 10 64-Bit
• Steps to reproduce this:
  Using the p5.erase() function before any 3D drawing method. E.g., plane(), box(), sphere()

I have made simple sketch demonstrating the issue here ( see lines 45-48 ):
https://editor.p5js.org/s5046715/sketches/VcMfSNV1o
There is a red div positioned behind the canvas ( with the same dimensions as the canvas ).

[tonyrobots]

I wonder if this is related to the bug I just filed: #5451

Take a look at my fork of your code, where I remove the Erase() and noErase() calls, and just add a semi-transparent fill -- it actually does the erase, which it shouldn't be: https://editor.p5js.org/tonyrobots/sketches/_5-tk6PL0

[gmaster350]

Extremely interesting find. I've made a new fork off of yours, where you can change the alpha of the plane interactively, plus enable or disable use of erase().
https://editor.p5js.org/s5046715/sketches/9vgMGlzDQ

They do seem related issues, you're right