From 9b287f7a6eb6f8a95d75a80856811a979634d511 Mon Sep 17 00:00:00 2001 From: nucular Date: Wed, 7 May 2014 18:03:57 +0200 Subject: [PATCH] Main synthesizing iterator --- sfxr.lua | 177 +++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 164 insertions(+), 13 deletions(-) diff --git a/sfxr.lua b/sfxr.lua index 22caf04..19f47ee 100644 --- a/sfxr.lua +++ b/sfxr.lua @@ -45,7 +45,7 @@ local function maybe(n) end local function clamp(n, min, max) - return math.max(min or -math.inf, math.min(max or math.inf, n)) + return math.max(min or -math.huge, math.min(max or math.huge, n)) end local function cpypol(a, b) @@ -81,7 +81,7 @@ function sfxr.Sound:__init() self:resetBuffers() end -function sfxr:resetParameters() +function sfxr.Sound:resetParameters() -- Set all parameters to the default values self.repeatSpeed = 0.0 self.waveType = sfxr.SQUARE @@ -120,18 +120,18 @@ function sfxr:resetParameters() self.highpass.sweep = 0.0 end -function sfxr:resetBuffers() +function sfxr.Sound:resetBuffers() -- Reset the sample buffers for i=1, 1025 do self.phaserBuffer[i] = 0 end for i=1, 33 do - self.noiseBuffer[i] = sfxr.random(-1, 1) + self.noiseBuffer[i] = random(-1, 1) end end -function sfxr:generate() +function sfxr.Sound:generate() -- Basically the main synthesizing function, yields the sample data -- Initialize ALL the locals! @@ -148,7 +148,7 @@ function sfxr:generate() local square_slide = -self.duty.sweep * 0.00005 local env_vol = 0 - local env_stage = 0 + local env_stage = 1 local env_time = 0 local env_length = {self.envelope.attack^2 * 100000, self.envelope.sustain^2 * 100000, @@ -158,14 +158,15 @@ function sfxr:generate() phase = cpypol(phase, self.phaser.offset) local dphase = self.phaser.sweep^2 dphase = cpypol(dphase, self.phaser.sweep) + local ipp = 0 - local iphase = math.abs(trunc(fphase)) + local iphase = math.abs(trunc(phase)) local ltp = 0 local ltdp = 0 local ltw = self.lowpass.cutoff^3 * 0.1 - local ltw_d = 1 + self.lowpass.ramp * 0.0001 - local ltdmp = 5 / (1 + self.lowpass.resonance^2 * 20) * (0.01 + fltw) + local ltw_d = 1 + self.lowpass.sweep * 0.0001 + local ltdmp = 5 / (1 + self.lowpass.resonance^2 * 20) * (0.01 + ltw) ltdmp = clamp(ltdmp, nil, 0.8) local ltphp = 0 local lthp = self.highpass.cutoff^2 * 0.1 @@ -176,16 +177,166 @@ function sfxr:generate() local vib_amp = self.vibrato.depth * 0.5 local chg_time = 0 + local chg_limit = 0 if self.change.speed == 1 then - local chg_limit = 0 + chg_limit = 0 else - local chg_limit = (1 - self.change.speed)^2 * 20000 + 32 + chg_limit = (1 - self.change.speed)^2 * 20000 + 32 end + local chg_mod = 0 if self.change.amount >= 0 then - local chg_mod = 1.0 - self.change.amount^2 * 0.9 + chg_mod = 1.0 - self.change.amount^2 * 0.9 else - local chg_mod = 1.0 - self.change.amount^2 * 10 + chg_mod = 1.0 - self.change.amount^2 * 10 + end + + -- Yay, the main closure + + return function() + -- Update the change time and apply it if needed + chg_time = chg_time + 1 + if chg_limit ~= 0 and chg_time >= chg_limit then + chg_limit = 0 + fperiod = fperiod * chg_mod + end + + -- Apply the frequency slide and stuff + slide = slide + dslide + fperiod = fperiod * slide + + if fperiod > maxperiod then + fperiod = fmaxperiod + -- If the frequency is too low, stop generating + if (self.frequency.min > 0) then + return nil + end + end + + -- Vibrato + local rfperiod = fperiod + if vib_amp > 0 then + vib_phase = vib_phase + vib_speed + rfperiod = fperiod * (1.0 + math.sin(vib_phase) * vib_amp) + end + -- Update the period + period = trunc(rfperiod) + if (period < 8) then period = 8 end + + -- Update the square duty + square_duty = clamp(square_duty + square_slide, 0, 0.5) + + -- Volume envelopes + + env_time = env_time + 1 + + if env_time > env_length[env_stage] then + env_time = 0 + env_stage = env_stage + 1 + -- After the decay stop generating + if env_stage == 4 then + return nil + end + end + + if env_stage == 1 then + env_vol = env_time / env_length[1] + elseif env_stage == 2 then + env_vol = 1 + (1 - env_time / env_length[2])^1 * 2 * self.envelope.punch + elseif env_stage == 3 then + env_vol = 1 - env_time / env_length[3] + end + + -- Phaser + + phase = phase + dphase + iphase = math.abs(trunc(phase)) + if iphase > 1024 then iphase = 1024 end + + -- Lowpass stuff + + if lthp_d ~= 0 then + lthp = clamp(lthp * lthp_d, 0.00001, 0.1) + end + + -- And finally the actual tone generation and supersampling + + local ssample = 0 + for si = 0, self.superSamples do + local sample = 0 + + phase = phase + 1 + + -- fill the noise buffer every period + if phase >= period then + --phase = 0 + phase = phase % period + if self.waveType == sfxr.NOISE then + for i = 1, 32 do + self.noiseBuffer[i] = random(-1, 1) + end + end + end + + -- Tone oscillators ahead!!! + + local fp = phase / period + + if self.waveType == sfxr.SQUARE then + if fp < square_duty then + sample = 0.5 + else + sample = -0.5 + end + + elseif self.waveType == sfxr.SAWTOOTH then + sample = 1 - fp * 2 + + elseif self.waveType == sfxr.SINE then + sample = math.sin(fp * 2 * math.pi) + + elseif self.waveType == sfxr.NOISE then + sample = self.noiseBuffer[math.floor(phase * 32 / period) + 1] + end + + -- Apply the lowpass filter to the sample + + local pp = ltp + ltw = clamp(ltw * ltw_d, 0, 0.1) + if self.lowpass.cutoff ~= 1 then + ltdp = ltdp + (sample - ltp) * ltw + ltdp = ltdp - ltdp * ltdmp + else + ltp = sample + ltdp = 0 + end + ltp = ltp + ltdp + + -- Apply the highpass filter to the sample + + ltphp = ltphp + ltp - pp + ltphp = ltphp - ltphp * lthp + sample = ltphp + + -- Apply the phaser to the sample + + self.phaserBuffer[bit.band(ipp, 1023) + 1] = sample + sample = sample + self.phaserBuffer[bit.band(ipp - iphase + 1024, 1023) + 1] + ipp = bit.band(ipp + 1, 1023) + + -- Accumulation and envelope application + ssample = ssample + sample * env_vol + end + + -- Apply the volumes + ssample = ssample / self.superSamples * self.volume.master + ssample = ssample * 2 * self.volume.sound + + -- Hard limit + ssample = clamp(ssample, -1, 1) + + -- Aaaand finally + return ssample end end