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Main synthesizing iterator
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nucular
parent
3cf88e042e
commit
9b287f7a6e
177
sfxr.lua
177
sfxr.lua
@ -45,7 +45,7 @@ local function maybe(n)
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end
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local function clamp(n, min, max)
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return math.max(min or -math.inf, math.min(max or math.inf, n))
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return math.max(min or -math.huge, math.min(max or math.huge, n))
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end
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local function cpypol(a, b)
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@ -81,7 +81,7 @@ function sfxr.Sound:__init()
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self:resetBuffers()
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end
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function sfxr:resetParameters()
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function sfxr.Sound:resetParameters()
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-- Set all parameters to the default values
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self.repeatSpeed = 0.0
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self.waveType = sfxr.SQUARE
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@ -120,18 +120,18 @@ function sfxr:resetParameters()
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self.highpass.sweep = 0.0
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end
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function sfxr:resetBuffers()
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function sfxr.Sound:resetBuffers()
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-- Reset the sample buffers
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for i=1, 1025 do
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self.phaserBuffer[i] = 0
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end
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for i=1, 33 do
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self.noiseBuffer[i] = sfxr.random(-1, 1)
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self.noiseBuffer[i] = random(-1, 1)
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end
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end
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function sfxr:generate()
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function sfxr.Sound:generate()
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-- Basically the main synthesizing function, yields the sample data
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-- Initialize ALL the locals!
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@ -148,7 +148,7 @@ function sfxr:generate()
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local square_slide = -self.duty.sweep * 0.00005
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local env_vol = 0
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local env_stage = 0
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local env_stage = 1
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local env_time = 0
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local env_length = {self.envelope.attack^2 * 100000,
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self.envelope.sustain^2 * 100000,
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@ -158,14 +158,15 @@ function sfxr:generate()
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phase = cpypol(phase, self.phaser.offset)
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local dphase = self.phaser.sweep^2
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dphase = cpypol(dphase, self.phaser.sweep)
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local ipp = 0
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local iphase = math.abs(trunc(fphase))
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local iphase = math.abs(trunc(phase))
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local ltp = 0
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local ltdp = 0
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local ltw = self.lowpass.cutoff^3 * 0.1
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local ltw_d = 1 + self.lowpass.ramp * 0.0001
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local ltdmp = 5 / (1 + self.lowpass.resonance^2 * 20) * (0.01 + fltw)
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local ltw_d = 1 + self.lowpass.sweep * 0.0001
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local ltdmp = 5 / (1 + self.lowpass.resonance^2 * 20) * (0.01 + ltw)
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ltdmp = clamp(ltdmp, nil, 0.8)
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local ltphp = 0
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local lthp = self.highpass.cutoff^2 * 0.1
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@ -176,16 +177,166 @@ function sfxr:generate()
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local vib_amp = self.vibrato.depth * 0.5
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local chg_time = 0
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if self.change.speed == 1 then
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local chg_limit = 0
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if self.change.speed == 1 then
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chg_limit = 0
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else
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local chg_limit = (1 - self.change.speed)^2 * 20000 + 32
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chg_limit = (1 - self.change.speed)^2 * 20000 + 32
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end
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local chg_mod = 0
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if self.change.amount >= 0 then
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local chg_mod = 1.0 - self.change.amount^2 * 0.9
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chg_mod = 1.0 - self.change.amount^2 * 0.9
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else
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local chg_mod = 1.0 - self.change.amount^2 * 10
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chg_mod = 1.0 - self.change.amount^2 * 10
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end
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-- Yay, the main closure
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return function()
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-- Update the change time and apply it if needed
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chg_time = chg_time + 1
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if chg_limit ~= 0 and chg_time >= chg_limit then
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chg_limit = 0
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fperiod = fperiod * chg_mod
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end
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-- Apply the frequency slide and stuff
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slide = slide + dslide
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fperiod = fperiod * slide
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if fperiod > maxperiod then
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fperiod = fmaxperiod
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-- If the frequency is too low, stop generating
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if (self.frequency.min > 0) then
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return nil
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end
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end
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-- Vibrato
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local rfperiod = fperiod
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if vib_amp > 0 then
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vib_phase = vib_phase + vib_speed
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rfperiod = fperiod * (1.0 + math.sin(vib_phase) * vib_amp)
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end
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-- Update the period
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period = trunc(rfperiod)
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if (period < 8) then period = 8 end
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-- Update the square duty
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square_duty = clamp(square_duty + square_slide, 0, 0.5)
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-- Volume envelopes
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env_time = env_time + 1
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if env_time > env_length[env_stage] then
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env_time = 0
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env_stage = env_stage + 1
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-- After the decay stop generating
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if env_stage == 4 then
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return nil
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end
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end
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if env_stage == 1 then
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env_vol = env_time / env_length[1]
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elseif env_stage == 2 then
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env_vol = 1 + (1 - env_time / env_length[2])^1 * 2 * self.envelope.punch
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elseif env_stage == 3 then
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env_vol = 1 - env_time / env_length[3]
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end
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-- Phaser
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phase = phase + dphase
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iphase = math.abs(trunc(phase))
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if iphase > 1024 then iphase = 1024 end
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-- Lowpass stuff
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if lthp_d ~= 0 then
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lthp = clamp(lthp * lthp_d, 0.00001, 0.1)
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end
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-- And finally the actual tone generation and supersampling
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local ssample = 0
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for si = 0, self.superSamples do
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local sample = 0
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phase = phase + 1
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-- fill the noise buffer every period
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if phase >= period then
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--phase = 0
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phase = phase % period
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if self.waveType == sfxr.NOISE then
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for i = 1, 32 do
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self.noiseBuffer[i] = random(-1, 1)
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end
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end
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end
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-- Tone oscillators ahead!!!
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local fp = phase / period
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if self.waveType == sfxr.SQUARE then
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if fp < square_duty then
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sample = 0.5
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else
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sample = -0.5
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end
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elseif self.waveType == sfxr.SAWTOOTH then
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sample = 1 - fp * 2
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elseif self.waveType == sfxr.SINE then
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sample = math.sin(fp * 2 * math.pi)
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elseif self.waveType == sfxr.NOISE then
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sample = self.noiseBuffer[math.floor(phase * 32 / period) + 1]
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end
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-- Apply the lowpass filter to the sample
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local pp = ltp
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ltw = clamp(ltw * ltw_d, 0, 0.1)
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if self.lowpass.cutoff ~= 1 then
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ltdp = ltdp + (sample - ltp) * ltw
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ltdp = ltdp - ltdp * ltdmp
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else
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ltp = sample
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ltdp = 0
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end
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ltp = ltp + ltdp
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-- Apply the highpass filter to the sample
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ltphp = ltphp + ltp - pp
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ltphp = ltphp - ltphp * lthp
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sample = ltphp
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-- Apply the phaser to the sample
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self.phaserBuffer[bit.band(ipp, 1023) + 1] = sample
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sample = sample + self.phaserBuffer[bit.band(ipp - iphase + 1024, 1023) + 1]
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ipp = bit.band(ipp + 1, 1023)
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-- Accumulation and envelope application
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ssample = ssample + sample * env_vol
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end
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-- Apply the volumes
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ssample = ssample / self.superSamples * self.volume.master
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ssample = ssample * 2 * self.volume.sound
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-- Hard limit
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ssample = clamp(ssample, -1, 1)
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-- Aaaand finally
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return ssample
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end
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end
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