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local luaxfade = pd.Class:new():register("luaxfade~")
function luaxfade:initialize(sel, atoms)
self.inlets = {SIGNAL,SIGNAL}
self.outlets = {SIGNAL}
self.xfade = 0
self.xfade_to = 0
self.xfade_time = 0
self.xfade_delay = 0
self.time = 0
self.ramp = 0
return true
end
function luaxfade:dsp(samplerate, blocksize)
self.samplerate = samplerate
end
function luaxfade:in_1_fade(atoms)
-- If self.samplerate is not initialized, because the dsp method has not
-- been run yet, then we cannot compute the sample delay and ramp times
-- below, so we bail out, telling the user to enable dsp first.
if not self.samplerate then
self:error("luaxfade~: unknown sample rate, please enable dsp first")
return
end
local fade, time, delay = table.unpack(atoms)
if type(delay) == "number" then
-- delay time (msec -> samples)
self.xfade_delay = math.floor(self.samplerate*delay/1000)
end
if type(time) == "number" then
-- xfade time (msec -> samples)
self.xfade_time = math.floor(self.samplerate*time/1000)
end
if type(fade) == "number" then
-- new xfade value (clamp to 0-1)
self.xfade_to = math.max(0, math.min(1, fade))
end
if self.xfade_to ~= self.xfade then
-- start a new cycle
if self.xfade_delay > 0 then
self.time, self.ramp = self.xfade_delay, 0
elseif self.xfade_time > 0 then
self.time, self.ramp = self.xfade_time, (self.xfade_to-self.xfade)/self.xfade_time
else
self.xfade = self.xfade_to
self.time, self.ramp = 0, 0
end
end
end
function luaxfade:perform(in1, in2)
local xfade, xfade_to = self.xfade, self.xfade_to
local xfade_time = self.xfade_time
local time, ramp = self.time, self.ramp
-- loop through each sample index
for i = 1, #in1 do
-- mix (we do this in-place, using in1 for output)
in1[i] = in1[i]*(1-xfade) + in2[i]*xfade
-- update the mix if time > 0 (sample countdown)
if time > 0 then
-- update cycle is still in ptogress
if ramp ~= 0 then
xfade = xfade + ramp
end
time = time - 1
elseif xfade_to ~= xfade then
if xfade_time > 0 then
-- start the ramp up or down
time, ramp = xfade_time, (xfade_to-xfade)/xfade_time
else
-- no xfade_time, jump to the new value immediately
xfade = xfade_to
end
end
end
-- update internal state
self.xfade, self.time, self.ramp = xfade, time, ramp
-- return the mixed down sample data
return in1
end
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