sfxr.lua/sfxr.lua

-- sfxr.lua
-- original by Tomas Pettersson, ported to Lua by nucular

--[[
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
]]--

local sfxr = {}

-- Constants

sfxr.SQUARE = 0
sfxr.SAWTOOTH = 1
sfxr.SINE = 2
sfxr.NOISE = 3

sfxr.FREQ_44100 = 44100
sfxr.FREQ_22050 = 22050
sfxr.BITS_FLOAT = 0
sfxr.BITS_16 = 16
sfxr.BITS_8 = 8

-- Utilities

local function trunc(n)
    return math.floor(n - 0.5)
end

local function random(low, high)
    return low + math.random() * (high - low)
end

local function maybe(n)
    return trunc(random(0, n or 1)) == 0
end

local function clamp(n, min, max)
    return math.max(min or -math.huge, math.min(max or math.huge, n))
end

local function cpypol(a, b)
    if b < 0 then
        return -a
    else
        return a
    end
end

local function setseed(seed)
    math.randomseed(seed)
    for i=0, 5 do
        math.random()
    end
end

-- Constructor

function sfxr.newSound(...)
    local instance = setmetatable({}, sfxr.Sound)
    instance:__init(...)
    return instance
end

-- The main Sound class

sfxr.Sound = {}
sfxr.Sound.__index = sfxr.Sound

function sfxr.Sound:__init()
    -- Build tables to store the parameters in
    self.volume = {}
    self.envelope = {}
    self.frequency = {}
    self.vibrato = {}
    self.change = {}
    self.duty = {}
    self.phaser = {}
    self.lowpass = {}
    self.highpass = {}

    -- Phaser and noise buffers
    self.phaserBuffer = {}
    self.noiseBuffer = {}

    self:resetParameters()
    self:resetBuffers()
end

function sfxr.Sound:resetParameters()
    -- Set all parameters to the default values
    self.repeatSpeed = 0.0
    self.waveType = sfxr.SQUARE
    self.superSamples = 8

    self.volume.master = 0.5
    self.volume.sound = 0.5

    self.envelope.attack = 0.0
    self.envelope.sustain = 0.3
    self.envelope.punch = 0.0
    self.envelope.decay = 0.4

    self.frequency.start = 0.3
    self.frequency.min = 0.0
    self.frequency.slide = 0.0
    self.frequency.deltaSlide = 0.0

    self.vibrato.depth = 0.0
    self.vibrato.speed = 0.0
    self.vibrato.delay = 0.0

    self.change.amount = 0.0
    self.change.speed = 0.0
    
    self.duty.ratio = 0.0
    self.duty.sweep = 0.0

    self.phaser.offset = 0.0
    self.phaser.sweep = 0.0

    self.lowpass.cutoff = 1.0
    self.lowpass.sweep = 0.0
    self.lowpass.resonance = 0.0
    self.highpass.cutoff = 0.0
    self.highpass.sweep = 0.0
end

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] = random(-1, 1)
    end
end

function sfxr.Sound:generate(freq, bits)
    -- Basically the main synthesizing function, yields the sample data

    freq = freq or sfxr.FREQ_44100
    bits = bits or sfxr.BITS_FLOAT
    assert(freq == sfxr.FREQ_44100 or freq == sfxr.FREQ_22050, "Invalid freq argument")
    assert(bits == sfxr.BITS_FLOAT or bits == sfxr.BITS_16 or bits == sfxr.BITS_8, "Invalid bits argument")

    -- Initialize ALL the locals!
    local fperiod, maxperiod
    local slide, dslide
    local square_duty, square_slide
    local chg_mod, chg_time, chg_limit

    local function reset()
        fperiod = 100 / ((self.frequency.start - 0.025)^2 + 0.001)
        maxperiod = 100 / (self.frequency.min^2 + 0.001)
        period = trunc(fperiod)
        
        slide = 1.0 - self.frequency.slide^3 * 0.01
        dslide = -self.frequency.deltaSlide^3 * 0.000001

        square_duty = 0.5 - self.duty.ratio * 0.5
        square_slide = -self.duty.sweep * 0.00005

        chg_mod = 0
        if self.change.amount >= 0 then
            chg_mod = 1.0 - self.change.amount^2 * 0.9
        else
            chg_mod = 1.0 - self.change.amount^2 * 10
        end

        chg_time = 0
        chg_limit = 0
        if self.change.speed == 1 then
            chg_limit = 0
        else
            chg_limit = (1 - self.change.speed)^2 * 20000 + 32
        end
    end
    reset()

    local second_sample = false

    local env_vol = 0
    local env_stage = 1
    local env_time = 0
    local env_length = {self.envelope.attack^2 * 100000,
        self.envelope.sustain^2 * 100000,
        self.envelope.decay^2 * 100000}

    local phase = self.phaser.offset^2 * 1020
    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(phase))

    local fltp = 0
    local fltdp = 0
    local fltw = self.lowpass.cutoff^3 * 0.1
    local fltw_d = 1 + self.lowpass.sweep * 0.0001
    local fltdmp = 5 / (1 + self.lowpass.resonance^2 * 20) * (0.01 + fltw)
    fltdmp = clamp(fltdmp, nil, 0.8)
    local fltphp = 0
    local flthp = self.highpass.cutoff^2 * 0.1
    local flthp_d = 1 + self.highpass.sweep * 0.0003

    local vib_phase = 0
    local vib_speed = self.vibrato.speed^2 * 0.01
    local vib_amp = self.vibrato.depth * 0.5

    local rep_time = 0
    local rep_limit = trunc((1 - self.repeatSpeed)^2 * 20000 + 32)
    if self.repeatSpeed == 0 then
        rep_limit = 0
    end

    -- Yay, the main closure

    local function iter()
        -- Repeat maybe
        rep_time = rep_time + 1
        if rep_limit ~= 0 and rep_time >= rep_limit then
            rep_time = 0
            reset()
        end

        -- 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 = maxperiod
            -- 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 = clamp(math.abs(trunc(phase)), nil, 1023)

        -- Filter stuff

        if flthp_d ~= 0 then
            flthp = clamp(flthp * flthp_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, 33 do
                        self.noiseBuffer[i] = random(-1, 1)
                    end
                end
            end

            -- Tone oscillators ahead!!!

            -- update the base waveform
            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[trunc(phase * 32 / period) % 32 + 1]
            end

            -- Apply the lowpass filter to the sample

            local pp = fltp
            fltw = clamp(fltw * fltw_d, 0, 0.1)
            if self.lowpass.cutoff ~= 1 then
                fltdp = fltdp + (sample - fltp) * fltw
                fltdp = fltdp - fltdp * fltdmp
            else
                fltp = sample
                fltdp = 0
            end
            fltp = fltp + fltdp

            -- Apply the highpass filter to the sample

            fltphp = fltphp + fltp - pp
            fltphp = fltphp - fltphp * flthp
            sample = fltphp

            -- 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)

        -- Frequency conversion
        second_sample = not second_sample
        if freq == sfxr.FREQ_22050 and second_sample then
            -- hah!
            local nsample = iter()
            if nsample then
                return (ssample + nsample) / 2
            else
                return nil
            end
        end

        -- bit conversions
        if bits == sfxr.BITS_FLOAT then
            return ssample
        elseif bits == sfxr.BITS_16 then
            return trunc(ssample * 32000) % (256*256)
        else
            return ssample * 127 + 128
        end
    end

    return iter
end

function sfxr.Sound:getEnvelopeLimit(freq)
    local env_length = {self.envelope.attack^2 * 100000,
        self.envelope.sustain^2 * 100000,
        self.envelope.decay^2 * 100000}
    local limit = trunc(env_length[1] + env_length[2] + env_length[3] + 2)
    
    if freq == nil or freq == sfxr.FREQ_44100 then
        return limit
    elseif freq == sfxr.FREQ_22050 then
        return math.ceil(limit / 2)
    else
        error("Invalid freq argument")
    end
end

function sfxr.Sound:getLimit(freq)
    return self:getEnvelopeLimit(freq)
end

function sfxr.Sound:generateTable(freq, bits)
    local t = {}
    t[self:getLimit(freq)] = 0

    local i = 1
    for v in self:generate(freq, bits) do
        t[i] = v or 0
        i = i + 1
    end

    return t
end

function sfxr.Sound:generateSoundData(freq, bits)
    freq = freq or sfxr.FREQ_44100
    local tab = self:generateTable(freq, sfxr.BITS_FLOAT)
    local data = love.sound.newSoundData(#tab, freq, bits, 1)

    for i = 0, #tab - 1 do
        data:setSample(i, tab[i + 1])
    end

    return data
end

function sfxr.Sound:randomize(seed)
    if seed then setseed(seed) end
    self.repeatSpeed = random(1, 2)

    if maybe() then
        self.frequency.start = random(-1, 1)^3 + 0.5
    else
        self.frequency.start = random(-1, 1)^2
    end
    self.frequency.limit = 0
    self.frequency.slide = random(-1, 1)^5
    if self.frequency.start > 0.7 and self.frequency.slide > 0.2 then
        self.frequency.slide = -self.frequency.slide
    elseif self.frequency.start < 0.2 and self.frequency.slide <-0.05 then
        self.frequency.slide = -self.frequency.slide
    end
    self.frequency.deltaSlide = random(-1, 1)^3

    self.duty.ratio = random(-1, 1)
    self.duty.sweep = random(-1, 1)^3

    self.vibrato.depth = random(-1, 1)^3
    self.vibrato.speed = random(-1, 1)
    self.vibrato.delay = random(-1, 1)

    self.envelope.attack = random(-1, 1)^3
    self.envelope.sustain = random(-1, 1)^2
    self.envelope.punch = random(-1, 1)^2
    self.envelope.decay = random(-1, 1)
    
    if self.envelope.attack + self.envelope.sustain + self.envelope.decay < 0.2 then
        self.envelope.sustain = self.envelope.sustain + 0.2 + random(0, 0.3)
        self.envelope.decay = self.envelope.decay + 0.2 + random(0, 0.3)
    end

    self.lowpass.resonance = random(-1, 1)
    self.lowpass.cutoff = 1 - random(0, 1)^3
    self.lowpass.sweep = random(-1, 1)^3
    if self.lowpass.cutoff < 0.1 and self.lowpass.sweep < -0.05 then
        self.lowpass.sweep = -self.lowpass.sweep
    end
    self.highpass.cutoff = random(0, 1)^3
    self.highpass.sweep = random(-1, 1)^5

    self.phaser.offset = random(-1, 1)^3
    self.phaser.sweep = random(-1, 1)^3

    self.change.speed = random(-1, 1)
    self.change.amount = random(-1, 1)
end

function sfxr.Sound:mutate(amount, seed, changeFreq)
    if seed then setseed(seed) end
    local amount = (amount or 1)
    local a = amount / 20
    local b = (1 - a) * 10
    local changeFreq = changeFreq or true

    if changeFreq == true then
        if maybe(b) then self.frequency.start = self.frequency.start + random(-a, a) end
        if maybe(b) then self.frequency.slide = self.frequency.slide + random(-a, a) end
        if maybe(b) then self.frequency.deltaSlide = self.frequency.deltaSlide + random(-a, a) end
    end

    if maybe(b) then self.duty.ratio = self.duty.ratio + random(-a, a) end
    if maybe(b) then self.duty.sweep = self.duty.sweep + random(-a, a) end

    if maybe(b) then self.vibrato.depth = self.vibrato.depth + random(-a, a) end
    if maybe(b) then self.vibrato.speed = self.vibrato.speed + random(-a, a) end
    if maybe(b) then self.vibrato.delay = self.vibrato.delay + random(-a, a) end

    if maybe(b) then self.envelope.attack = self.envelope.attack + random(-a, a) end
    if maybe(b) then self.envelope.sustain = self.envelope.sustain + random(-a, a) end
    if maybe(b) then self.envelope.punch = self.envelope.punch + random(-a, a) end
    if maybe(b) then self.envelope.decay = self.envelope.decay + random(-a, a) end

    if maybe(b) then self.lowpass.resonance = self.lowpass.resonance + random(-a, a) end
    if maybe(b) then self.lowpass.cutoff = self.lowpass.cutoff + random(-a, a) end
    if maybe(b) then self.lowpass.sweep = self.lowpass.sweep + random(-a, a) end
    if maybe(b) then self.highpass.cutoff = self.highpass.cutoff + random(-a, a) end
    if maybe(b) then self.highpass.sweep = self.highpass.sweep + random(-a, a) end

    if maybe(b) then self.phaser.offset = self.phaser.offset + random(-a, a) end
    if maybe(b) then self.phaser.sweep = self.phaser.sweep + random(-a, a) end

    if maybe(b) then self.change.speed = self.change.speed + random(-a, a) end
    if maybe(b) then self.change.amount = self.change.amount + random(-a, a) end

    if maybe(b) then self.repeatSpeed = self.repeatSpeed + random(-a, a) end
end

function sfxr.Sound:randomPickup(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    self.frequency.start = random(0.4, 0.5)
    self.envelope.attack = 0
    self.envelope.sustain = random(0, 0.1)
    self.envelope.punch = random(0.3, 0.6)
    self.envelope.decay = random(0.1, 0.5)
    
    if maybe() then
        self.change.speed = random(0.5, 0.7)
        self.change.amount = random(0.4, 0.6)
    end
end

function sfxr.Sound:randomLaser(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    self.waveType = trunc(random(0, 2)) + 1
    if self.waveType == sfxr.SINE and maybe() then
        self.waveType = trunc(random(0, 1)) + 1
    end

    if maybe(2) then
        self.frequency.start = random(0.3, 0.9)
        self.frequency.min = random(0, 0.1)
        self.frequency.slide = -0.35 - random(0, 0.3)
    else
        self.frequency.start = random(0.5, 1)
        self.frequency.min = clamp(self.frequency.start - 0.5 - random(0, 0.6), 0.2)
        self.frequency.slide = -0.15 - random(0, 0.2)
    end

    if maybe() then
        self.duty.ratio = random(0, 0.5)
        self.duty.sweep = random(0, 0.2)
    else
        self.duty.ratio = random(0.4, 0.9)
        self.duty.sweep = -random(0, 0.7)
    end

    self.envelope.attack = 0
    self.envelope.sustain = random(0.1, 0.3)
    self.envelope.decay = random(0, 0.4)

    if maybe() then
        self.envelope.punch = random(0, 0.3)
    end

    if maybe(2) then
        self.phaser.offset = random(0, 0.2)
        self.phaser.sweep = -random(0, 0.2)
    end

    if maybe() then
        self.highpass.cutoff = random(0, 0.3)
    end
end

function sfxr.Sound:randomExplosion(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    self.waveType = sfxr.NOISE
    
    if maybe() then
        self.frequency.start = random(0.1, 0.5)
        self.frequency.slide = random(-0.1, 0.3)
    else
        self.frequency.start = random(0.2, 0.9)
        self.frequency.slide = -0.2 - random(0, 0.2)
    end
    self.frequency.start = self.frequency.start^2

    if maybe(4) then
        self.frequency.slide = 0
    end
    if maybe(2) then
        self.repeatSpeed = random(0.3, 0.8)
    end

    self.envelope.attack = 0
    self.envelope.sustain = random(0.1, 0.4)
    self.envelope.punch = random(0.2, 0.8)
    self.envelope.decay = random(0, 0.5)

    if maybe() then
        self.phaser.offset = random(-0.3, 0.6)
        self.phaser.sweep = -random(0, 0.3)
    end
    if maybe(2) then
        self.change.speed = random(0.6, 0.8)
        self.change.amount = random(0.8, 2.4)
    elseif maybe() then
        self.change.amount = random(0, 0.7)
        self.change.speed = random(0, 0.6)
    end
end

function sfxr.Sound:randomPowerup(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    if maybe() then
        self.waveType = sfxr.SAWTOOTH
    else
        self.duty.ratio = random(0, 0.6)
    end

    if maybe() then
        self.frequency.start = random(0.2, 0.5)
        self.frequency.slide = random(0.1, 0.5)
        self.repeatSpeed = random(0.4, 0.8)
    else
        self.frequency.start = random(0.2, 0.5)
        self.frequency.slide = random(0.1, 0.5)
        if maybe() then
            self.change.amount = random(0, 0.7)
            self.change.speed = random(0, 0.6)
        end
    end
    self.envelope.attack = 0
    self.envelope.sustain = random(0, 0.4)
    self.envelope.decay = random(0.1, 0.5)
end

function sfxr.Sound:randomHit(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    self.waveType = trunc(random(0, 2)) + 1

    if self.waveType == sfxr.SINE then
        self.waveType = 3
    elseif self.waveType == sfxr.SQUARE then
        self.duty.ratio = random(0, 0.6)
    end

    self.frequency.start = random(0.2, 0.8)
    self.frequency.glide = -0.3 - random(0, 0.4)
    self.envelope.attack = 0
    self.envelope.sustain = random(0, 0.1)
    self.envelope.decay = random(0.1, 0.3)

    if maybe() then
        self.highpass.cutoff = random(0, 0.3)
    end
end

function sfxr.Sound:randomJump(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    self.waveType = sfxr.SQUARE

    self.duty.value = random(0, 0.6)
    self.frequency.cutoff = random(0.3, 0.6)
    self.frequency.slide = random(0.1, 0.3)

    self.envelope.attack = 0
    self.envelope.sustain = random(0.1, 0.4)
    self.envelope.decay = random(0.1, 0.3)

    if maybe() then
        self.highpass.cutoff = random(0, 0.3)
    end
    if maybe() then
        self.lowpass.cutoff = 1 - random(0, 0.6)
    end
end

function sfxr.Sound:randomBlip(seed)
    if seed then setseed(seed) end
    self:resetParameters()
    self.waveType = trunc(random(0, 1)) + 1

    if self.waveType == 0 then
        self.duty.ratio = random(0, 0.6)
    end

    self.frequency.start = random(0.2, 0.6)
    self.envelope.attack = 0
    self.envelope.sustain = random(0.1, 0.2)
    self.envelope.decay = random(0, 0.2)
    self.highpass.cutoff = 0.1
end

return sfxr