Set the master volume for all channels.
int Mix_MasterVolume(int volume);
|volume||the new volume, between 0 and MIX_MAX_VOLUME, or -1 to query.|
Returns the previous volume. If the specified volume is -1, this returns the current volume.
SDL_mixer keeps a per-channel volume, a per-chunk volume, and a master volume, and considers all three when mixing audio. This function sets the master volume, which is applied to all playing channels when mixing.
The volume must be between 0 (silence) and MIX_MAX_VOLUME (full volume). Note that MIX_MAX_VOLUME is 128. Values greater than MIX_MAX_VOLUME are clamped to MIX_MAX_VOLUME.
Specifying a negative volume will not change the current volume; as such, this can be used to query the current volume without making changes, as this function returns the previous (in this case, still-current) value.
Note that the master volume does not affect any playing music; it is only applied when mixing chunks. Use Mix_MusicVolume() for that.
This function is available since SDL_mixer 2.6.0.