My example would be in Banjo-Kazooie for the Nintendo 64. As you move about the game and shift into different areas or near an object, the music will change. It's basically the same melody and rhythm, but one part of the song will have faded away and a new part would have faded in that is relative to the location or object.
For instance, the overworld would have a melody accompanied by strings. As the player nears a cave, the strings fade, and a marimba part fades in.
My question is not how they wrote this but how they implemented it in the game. Perhaps this is geared toward programming?
Do they have all possible parts playing and increase volume on cue? i.e.
on Default:stringsPart.play(100); //100% volumemarimbaPart.play(0); //silencepercussionPart.play(100); on NearCave:stringsPart.fadeout();marimbaPart.fadein();
Any clarification would be great. It doesn't make sense to me to have it all playing in the background at once at different volumes. Wouldn't that make it liable to become out of sync? Or make it have too much going on for the game to handle?