Fix BiomeSpecialEffectsBuilder to copy backgroundMusicVolume

[sciwhiz12]

This PR fixes #1733 by also copying backgroundMusicVolume in the copy factory for BiomeSpecialEffectsBuilder. Tested by checking that walking into a pale garden biome with background music playing causes the music to slowly fade out, and then fade back in when walking outside of the pale garden biome. See also #1766 (comment) for a bit more information.

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: 115ba26afb308cbe0876c2418b1fc70e3b4856e9.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:neoforge:21.4.40-beta-pr-1792-fix-1.21.4-GH-1733-pale-garden-music-fadeout
• 📦 net.neoforged:testframework:21.4.40-beta-pr-1792-fix-1.21.4-GH-1733-pale-garden-music-fadeout

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #1792' // https://github.com/neoforged/NeoForge/pull/1792
        url 'https://prmaven.neoforged.net/NeoForge/pr1792'
        content {
            includeModule('net.neoforged', 'neoforge')
            includeModule('net.neoforged', 'testframework')
        }
    }
}

MDK installation

In order to setup a MDK using the latest PR version, run the following commands in a terminal.
The script works on both *nix and Windows as long as you have the JDK bin folder on the path.
The script will clone the MDK in a folder named NeoForge-pr1792.
On Powershell you will need to remove the -L flag from the curl invocation.

mkdir NeoForge-pr1792
cd NeoForge-pr1792
curl -L https://prmaven.neoforged.net/NeoForge/pr1792/net/neoforged/neoforge/21.4.40-beta-pr-1792-fix-1.21.4-GH-1733-pale-garden-music-fadeout/mdk-pr1792.zip -o mdk.zip
jar xf mdk.zip
rm mdk.zip || del mdk.zip

To test a production environment, you can download the installer from here.

[neoforged-releases]

🚀 This PR has been released as NeoForge version 21.4.39-beta.