CLOSES #407, CLOSES #408, CLOSES #409, CLOSES #410, CLOSES #411, CLOSES #417

CLOSES #407, CLOSES #408, CLOSES #409, CLOSES #410, CLOSES #411, CLOSES #417

src/core/ChipAudio.lua

@@ -25,6 +25,29 @@ local SAMPLE_RATE = ChipSynth.SAMPLE_RATE
 local MUSIC_BUFFER_SAMPLES = ChipSynth.MUSIC_BUFFER_SAMPLES
 local MUSIC_BUFFER_COUNT = ChipSynth.MUSIC_BUFFER_COUNT
 
+-- ---------------------------------------------------------------------------
+-- Per-channel mix (edit these)
+-- Applied on load and whenever this file hot-reloads.
+-- Runtime: ChipAudio.setChannelVolume / setChannelPitch.
+--   [1] pulse 1   [2] pulse 2   [3] wave   [4] noise / drums
+-- Volume: 1 = authentic, 0 = mute, >1 boosts
+-- Pitch:  1 = authentic, 2 = +1 octave, 0.5 = -1 octave
+-- ---------------------------------------------------------------------------
+local CHANNEL_VOLUME = {
+  [1] = 1, -- pulse 1
+  [2] = 1, -- pulse 2
+  [3] = 0.25, -- wave
+  [4] = 1, -- noise / drums
+}
+local CHANNEL_PITCH = {
+  [1] = 1, -- pulse 1
+  [2] = 1, -- pulse 2
+  [3] = 0.5, -- wave
+  [4] = 1, -- noise / drums
+}
+ChipSynth.setChannelVolumes(CHANNEL_VOLUME)
+ChipSynth.setChannelPitches(CHANNEL_PITCH)
+
 -- currentMusic: { source, gen, threaded, started, finished, engine }
 --   threaded songs stream from the worker (engine is nil here);
 --   the fallback path owns a local engine and fills the source itself.
@@ -152,13 +175,23 @@ function ChipAudio.playMusic(data, header, allowLoops)
   musicGen = musicGen + 1
   local gen = musicGen
   cmdCh:push({ cmd = "play", gen = gen, header = header,
-               allowLoops = allowLoops, audio = slimAudio(data) })
+               allowLoops = allowLoops, audio = slimAudio(data),
+               channelVolumes = ChipSynth.getChannelVolumes(),
+               channelPitches = ChipSynth.getChannelPitches() })
   currentMusic = { source = source, gen = gen, threaded = true,
                    started = false, finished = false }
   -- playback starts in update() once the first buffer arrives (~1 frame)
   return source
 end
 
+local function pushChannelMix()
+  if workerReady and cmdCh then
+    cmdCh:push({ cmd = "channelMix",
+                 volumes = ChipSynth.getChannelVolumes(),
+                 pitches = ChipSynth.getChannelPitches() })
+  end
+end
+
 -- move finished buffers from the worker into the Source; start playback once
 -- the first one lands
 local function updateThreaded()
@@ -270,6 +303,53 @@ function ChipAudio.invalidate()
   if workerReady and cmdCh then cmdCh:push({ cmd = "invalidate" }) end
 end
 
+-- Runtime mix for one hardware channel (1..4).  Takes effect on the next
+-- synthesized buffer (live music) and on any SFX/cry rendered after the call.
+function ChipAudio.setChannelVolume(hw, scale)
+  ChipSynth.setChannelVolume(hw, scale)
+  pushChannelMix()
+end
+
+function ChipAudio.getChannelVolume(hw)
+  return ChipSynth.getChannelVolume(hw)
+end
+
+function ChipAudio.setChannelVolumes(volumes)
+  ChipSynth.setChannelVolumes(volumes)
+  pushChannelMix()
+end
+
+function ChipAudio.getChannelVolumes()
+  return ChipSynth.getChannelVolumes()
+end
+
+function ChipAudio.setChannelPitch(hw, scale)
+  ChipSynth.setChannelPitch(hw, scale)
+  pushChannelMix()
+end
+
+function ChipAudio.getChannelPitch(hw)
+  return ChipSynth.getChannelPitch(hw)
+end
+
+function ChipAudio.setChannelPitches(pitches)
+  ChipSynth.setChannelPitches(pitches)
+  pushChannelMix()
+end
+
+function ChipAudio.getChannelPitches()
+  return ChipSynth.getChannelPitches()
+end
+
+-- aliases for channel 4 (noise / drums)
+function ChipAudio.setNoiseVolume(scale)
+  ChipAudio.setChannelVolume(4, scale)
+end
+
+function ChipAudio.getNoiseVolume()
+  return ChipAudio.getChannelVolume(4)
+end
+
 -- a stale song must not keep sounding past the flush that replaced its
 -- program (20 §2 cache contract, chip music row)
 Assets.register(ChipAudio.invalidate)

src/core/ChipSynth.lua

@@ -29,6 +29,71 @@ ChipSynth.SAMPLE_RATE = SAMPLE_RATE
 ChipSynth.MUSIC_BUFFER_SAMPLES = MUSIC_BUFFER_SAMPLES
 ChipSynth.MUSIC_BUFFER_COUNT = MUSIC_BUFFER_COUNT
 
+-- Runtime mix per hardware channel (1 pulse, 2 pulse, 3 wave, 4 noise).
+-- Volume: 1 = authentic GB, 0 = mute.  Pitch: 1 = authentic, 2 = +1 octave,
+-- 0.5 = -1 octave.  Applied at sample time so a live change reaches the next
+-- buffer on both the sync path and the worker (via ChipAudio).
+local channelVolume = { 1, 1, 1, 1 }
+local channelPitch = { 1, 1, 1, 1 }
+
+local function clampScale(scale)
+  return math.max(0, tonumber(scale) or 0)
+end
+
+local function setChannelTable(table, hw, scale)
+  hw = tonumber(hw)
+  if not hw or hw < 1 or hw > 4 then return end
+  table[hw] = clampScale(scale)
+end
+
+local function setChannelTables(table, values)
+  if type(values) ~= "table" then return end
+  for hw = 1, 4 do
+    if values[hw] ~= nil then table[hw] = clampScale(values[hw]) end
+  end
+end
+
+function ChipSynth.setChannelVolume(hw, scale)
+  setChannelTable(channelVolume, hw, scale)
+end
+
+function ChipSynth.getChannelVolume(hw)
+  return channelVolume[tonumber(hw) or 0] or 1
+end
+
+function ChipSynth.setChannelVolumes(volumes)
+  setChannelTables(channelVolume, volumes)
+end
+
+function ChipSynth.getChannelVolumes()
+  return { channelVolume[1], channelVolume[2], channelVolume[3], channelVolume[4] }
+end
+
+function ChipSynth.setChannelPitch(hw, scale)
+  setChannelTable(channelPitch, hw, scale)
+end
+
+function ChipSynth.getChannelPitch(hw)
+  return channelPitch[tonumber(hw) or 0] or 1
+end
+
+function ChipSynth.setChannelPitches(pitches)
+  setChannelTables(channelPitch, pitches)
+end
+
+function ChipSynth.getChannelPitches()
+  return { channelPitch[1], channelPitch[2], channelPitch[3], channelPitch[4] }
+end
+
+-- aliases for the noise/drum layer
+function ChipSynth.setNoiseVolume(scale)
+  ChipSynth.setChannelVolume(4, scale)
+end
+
+function ChipSynth.getNoiseVolume()
+  return ChipSynth.getChannelVolume(4)
+end
+
 local PITCHES = {
   0xF82C, 0xF89D, 0xF907, 0xF96B, 0xF9CA, 0xFA23,
   0xFA77, 0xFAC7, 0xFB12, 0xFB58, 0xFB9B, 0xFBDA,
@@ -430,7 +495,8 @@ function Channel:sampleNoise(parameter)
   local divisor = NOISE_DIVISORS[bit.band(parameter, 7)]
   local shift = bit.rshift(parameter, 4)
   if shift < 14 then
-    local cycles = GB_CLOCK / divisor / (2 ^ shift) / SAMPLE_RATE
+    local pitch = channelPitch[self.hardware] or 1
+    local cycles = GB_CLOCK / divisor / (2 ^ shift) / SAMPLE_RATE * pitch
     local width7 = bit.band(parameter, 8) ~= 0
     local remaining = cycles
     while remaining > 0 do
@@ -500,11 +566,14 @@ function Channel:sample()
   event.sample = sampleIndex + 1
   if event.silence then return 0 end
 
-  if event.drum then return self:sampleDrum(event, sampleIndex) end
+  local gain = channelVolume[self.hardware] or 1
+  if event.drum then
+    return self:sampleDrum(event, sampleIndex) * gain
+  end
   local volume = envelopeVolume(
     event.volume or 0, event.fade or 0, event.elapsed)
   if event.noise then
-    return self:sampleNoise(event.noiseParameter) * volume / 15
+    return self:sampleNoise(event.noiseParameter) * volume / 15 * gain
   end
 
   local register = event.register
@@ -529,7 +598,8 @@ function Channel:sample()
       end
     end
   end
-  local frequency = 131072 / (2048 - math.min(register, 2047))
+  local pitch = channelPitch[self.hardware] or 1
+  local frequency = 131072 / (2048 - math.min(register, 2047)) * pitch
   if event.wave then frequency = frequency * 0.5 end
   local phase = self.phase
   self.phase = (phase + frequency / SAMPLE_RATE) % 1
@@ -539,7 +609,7 @@ function Channel:sample()
     -- a def-local program may omit its wave table entirely
     if not wave then return 0 end
     local index = math.min(32, math.floor(phase * 32) + 1)
-    return wave[index] * event.waveLevel
+    return wave[index] * event.waveLevel * gain
   end
   local duty = event.duty
   if type(duty) == "table" then
@@ -548,9 +618,9 @@ function Channel:sample()
   local pattern = WAVE_PATTERN_TABLES[duty or 2] or WAVE_PATTERN_TABLES[2]
   local step = math.floor(phase * 8) % 8
   if pattern[step + 1] == 0 then
-    return -volume / 15
+    return -volume / 15 * gain
   end
-  return volume / 15
+  return volume / 15 * gain
 end
 
 local Engine = {}

src/core/chip_worker.lua

@@ -5,8 +5,10 @@
 --
 -- Protocol -- main thread pushes command tables onto the "chipaudio_cmd"
 -- channel and drains produced buffers off "chipaudio_out":
---   cmd = "play"  { gen, header, allowLoops, audio }  start a song
+--   cmd = "play"  { gen, header, allowLoops, audio,
+--                   channelVolumes?, channelPitches? }
 --   cmd = "stop"                                       halt production
+--   cmd = "channelMix" { volumes, pitches }            per-hw volume/pitch
 --   cmd = "invalidate"                                 drop the bank cache
 --   cmd = "quit"                                        end the thread
 -- out buffers are tagged with the play's `gen` so the main thread can
@@ -45,6 +47,12 @@ local function handle(cmd)
     engine = nil
     outCh:clear() -- drop any buffers left from the previous song
     data = { audio = cmd.audio }
+    if cmd.channelVolumes ~= nil then
+      ChipSynth.setChannelVolumes(cmd.channelVolumes)
+    end
+    if cmd.channelPitches ~= nil then
+      ChipSynth.setChannelPitches(cmd.channelPitches)
+    end
     local ok, eng = pcall(ChipSynth.newEngine, data, cmd.header,
                           { allowLoops = cmd.allowLoops })
     if ok then
@@ -58,6 +66,9 @@ local function handle(cmd)
     engine = nil
     finished = false
     outCh:clear()
+  elseif cmd.cmd == "channelMix" then
+    if cmd.volumes ~= nil then ChipSynth.setChannelVolumes(cmd.volumes) end
+    if cmd.pitches ~= nil then ChipSynth.setChannelPitches(cmd.pitches) end
   elseif cmd.cmd == "invalidate" then
     ChipSynth.invalidateBanks()
   elseif cmd.cmd == "quit" then