P2D and P3D renderers don't set `WM_CLASS` for Linux

Created by: @ColdMacaroni

Description

When running a sketch that uses the P2D or P3D renderer. The WM_CLASS window variable is not set. This makes it difficult (impossible?) to set window rules for the resulting window. (For example, making it so a tiling window manager makes the window float by default, instead of resizing it.)

Expected Behavior

WM_CLASS should be set to "Processing", "processing-sketch" or similar. For reference, the main processing app has a WM_CLASS of "Processing", "Processing" and a sketch with the default renderer has a WM_CLASS of "processing-core-PApplet", "processing-core-PApplet".

Current Behavior

The WM_CLASS variable is not set. (I don't mean empty, it just doesn't exist)

Steps to Reproduce

1. Run a sketch that uses P2D or P3D as a renderer. Example code:

size(128, 128, P2D);

2. Inspect the window class with xprop (or another similar tool). To use xprop, simply run it on a terminal and click on the window. You can also pipe it into grep to filter out the other variables: xprop | grep WM_CLASS

Your Environment

• Processing version: 4.3 (1293)
• Operating System and OS version: Arch Linux (kernel 6.4.12-arch1-1)
• Other information:
  • Xorg server version: 21.1.8
  • Tested with the following window managers:
    • AwesomeWM
    • XMonad
    • Hyprland (through XWayland)