[macOS] Undesired behaviour when setting master volume to zero

[Langbart]

• reported in the forum by kpatch
  • ​Master Volume not working as expected (30/Mar/23)

to reproduce

• open the Sound options and set Master volume to 0.00, click Save
  • everything is silent
• restart 0 A.D.
  • sound can be heard at the normal default sound level, when checking the options the Master volume is still at 0.00
• change the Master volume to 0.01, click Save
  • everything is very quiet, but you can still hear something
• restart 0 A.D.
  • sound remains very quiet

expected behavior

• setting Master Volume to 0.00 should disable the sound even when the game is restarted.

note

• the two command line options quickstart and nosound reliably turn off the sound as expected
  • see binaries/system/readme.txt​

    Line
    6	-mod=NAME start the game using NAME mod
    7	-quickstart load faster (disables audio and some system info logging)
    8

    Line
    48	Configuration:
    49	-conf=KEY:VALUE set a config value
    50	-nosound disable audio
    51	-shadows enable shadows

reproducible

• very old bug, issue can be reproduced in Alpha XV - Osiris [14386], didn't test any further

likely related commit

• [12428] by stwf (aka "Steven Fuchs")
  • New sound system implementation by stwf, refs #1223, #961.
  • Enables audio on OS X, refs #685, #931.
  • Fixes music not playing after a game, refs #946.