Tween gain for audio

Feature requests
#1

I was wondering if we could have a built in tween function for gain on sounds. I’d love to be able to crossfade my looping music dynamically and in a smooth manner. It seems like it would be useful. I’m sure I could do it by hand with a bunch of nested function but I’d rather not have to.

What I’m doing currently:

go.property("crossfadeVariable", 0)

local startGain = 0.0
local stopGain = 1.0

function crossfade_audio(start, stop)
	if startGain < 1.0 and stopGain > 0.0 then
		go.animate("#", "crossfadeVariable", go.PLAYBACK_ONCE_FORWARD, 1, go.EASING_LINEAR, 0.025, 0, function ()
				startGain = startGain + 0.1
				stopGain = stopGain - 0.1
				msg.post(start, "set_gain", {gain = startGain})
				msg.post(stop, "set_gain", {gain = stopGain})
				crossfade_audio(start, stop)
			end)
	elseif
		msg.post(stop, "stop_sound")
	end
end


function on_message(self, message_id, message, sender)
	if message_id == hash("to_main_menu") then
		if self.state ~= "MAIN_MENU" then
			msg.post("#boardproxy", "unload")
			startGain = 0.0
			stopGain = 1.0
			msg.post("#MenuMusic", "play_sound", { gain = startGain })
			crossfade_audio("#BoardMusic","#MenuMusic")
		else
			msg.post("#MenuMusic", "play_sound", { gain = 1.0 })
		end
		msg.post("main:/main#menu", "enable")
		msg.post("#background", "enable")
		self.state = "MAIN_MENU"
		
	elseif message_id == hash("start_game") then
		msg.post("#background", "disable")
		msg.post("#boardproxy", "load")
		msg.post("#menu", "disable")
	elseif message_id == hash("proxy_loaded") then
		-- Board collection has loaded...
		msg.post(sender, "init")
		startGain = 0.0
		stopGain = 1.0
		msg.post("#BoardMusic", "play_sound", { gain = startGain })
		crossfade_audio("#BoardMusic","#MenuMusic")
		msg.post("board:/board#script", "start_level")
		msg.post(sender, "enable")
		self.state = "GAME_RUNNING"
	end    
end
2 Likes
#2

If you spawn a game-object for the sound or tween only one at a time you can use update.

function update(self, dt)
    sound.set_gain(self.sound_url, self.gain)
end

And animate that one, it doesnt solve the convenience problem but offers a simpler to follow code at least

2 Likes
#3

I’de like to see this feature as well. need to make main theme quieter than final popup sound when it appear (level done).

#4

This might help for now

2 Likes