Audio_Effects OK and Documented (#549)

* Audio_Effects OK

* Remove duplicate

* PR Suggestion

* Small cleanup

* Small Touchup

2 files changed, 331 insertions, 11 deletions

diff --git a/src/code/audio/audio_effects.c b/src/code/audio/audio_effects.c
index e795d5e9f..2dcef2237 100644
--- a/src/code/audio/audio_effects.c
+++ b/src/code/audio/audio_effects.c
@@ -1,21 +1,341 @@
 #include "global.h"
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80196A00.s")
+void AudioEffects_SequenceChannelProcessSound(SequenceChannel* channel, s32 recalculateVolume, s32 applyBend) {
+    f32 channelVolume;
+    f32 chanFreqScale;
+    s32 i;
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80196BC8.s")
+    if (channel->changes.s.volume || recalculateVolume) {
+        channelVolume = channel->volume * channel->volumeScale * channel->seqPlayer->appliedFadeVolume;
+        if (channel->seqPlayer->muted && (channel->muteBehavior & 0x20)) {
+            channelVolume = channel->seqPlayer->muteVolumeScale * channelVolume;
+        }
+        channel->appliedVolume = channelVolume * channelVolume;
+    }
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80196D20.s")
+    if (channel->changes.s.pan) {
+        channel->pan = channel->newPan * channel->panChannelWeight;
+    }
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80196D7C.s")
+    chanFreqScale = channel->freqScale;
+    if (applyBend) {
+        chanFreqScale *= channel->seqPlayer->bend;
+        channel->changes.s.freqScale = true;
+    }
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80196DB4.s")
+    for (i = 0; i < ARRAY_COUNT(channel->layers); i++) {
+        SequenceLayer* layer = channel->layers[i];
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80196FEC.s")
+        if (layer != NULL && layer->enabled && layer->note != NULL) {
+            if (layer->notePropertiesNeedInit) {
+                layer->noteFreqScale = layer->freqScale * chanFreqScale;
+                layer->noteVelocity = layer->velocitySquare2 * channel->appliedVolume;
+                layer->notePan = (channel->pan + layer->pan * (0x80 - channel->panChannelWeight)) >> 7;
+                layer->notePropertiesNeedInit = false;
+            } else {
+                if (channel->changes.s.freqScale) {
+                    layer->noteFreqScale = layer->freqScale * chanFreqScale;
+                }
+                if (channel->changes.s.volume || recalculateVolume) {
+                    layer->noteVelocity = layer->velocitySquare2 * channel->appliedVolume;
+                }
+                if (channel->changes.s.pan) {
+                    layer->notePan = (channel->pan + layer->pan * (0x80 - channel->panChannelWeight)) >> 7;
+                }
+            }
+        }
+    }
+    channel->changes.asByte = 0;
+}
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80197048.s")
+void AudioEffects_SequencePlayerProcessSound(SequencePlayer* seqPlayer) {
+    s32 i;
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80197138.s")
+    if ((seqPlayer->fadeTimer != 0) && (seqPlayer->skipTicks == 0)) {
+        seqPlayer->fadeVolume += seqPlayer->fadeVelocity;
+        seqPlayer->recalculateVolume = true;
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80197164.s")
+        if (seqPlayer->fadeVolume > 1.0f) {
+            seqPlayer->fadeVolume = 1.0f;
+        }
+        if (seqPlayer->fadeVolume < 0.0f) {
+            seqPlayer->fadeVolume = 0.0f;
+        }
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_effects/func_80197188.s")
+        seqPlayer->fadeTimer--;
+        if (seqPlayer->fadeTimer == 0 && seqPlayer->state == 2) {
+            AudioSeq_SequencePlayerDisable(seqPlayer);
+            return;
+        }
+    }
+
+    if (seqPlayer->recalculateVolume) {
+        seqPlayer->appliedFadeVolume = seqPlayer->fadeVolume * seqPlayer->fadeVolumeScale;
+    }
+
+    for (i = 0; i < ARRAY_COUNT(seqPlayer->channels); i++) {
+        if (seqPlayer->channels[i]->enabled == true) {
+            AudioEffects_SequenceChannelProcessSound(seqPlayer->channels[i], seqPlayer->recalculateVolume,
+                                                     seqPlayer->applyBend);
+        }
+    }
+
+    seqPlayer->recalculateVolume = false;
+}
+
+f32 AudioEffects_GetPortamentoFreqScale(Portamento* portamento) {
+    u32 loResCur;
+    f32 portamentoFreq;
+
+    portamento->cur += portamento->speed;
+    loResCur = (portamento->cur >> 8) & 0xFF;
+
+    if (loResCur >= 127) {
+        loResCur = 127;
+        portamento->mode = 0;
+    }
+
+    portamentoFreq = AUDIO_LERPIMP(1.0f, gBendPitchOneOctaveFrequencies[loResCur + 128], portamento->extent);
+
+    return portamentoFreq;
+}
+
+s16 AudioEffects_GetVibratoPitchChange(VibratoState* vib) {
+    s32 index;
+
+    vib->time += (s32)vib->rate;
+    index = (vib->time >> 10) & 0x3F;
+    return vib->curve[index];
+}
+
+f32 AudioEffects_GetVibratoFreqScale(VibratoState* vib) {
+    static f32 activeVibratoFreqScaleSum = 0.0f;
+    static s32 activeVibratoCount = 0;
+    f32 pitchChange;
+    f32 extent;
+    f32 invExtent;
+    f32 result;
+    f32 scaledExtent;
+    VibratoSubStruct* subVib = vib->vibSubStruct;
+
+    if (vib->delay != 0) {
+        vib->delay--;
+        return 1.0f;
+    }
+
+    if (subVib != NULL) {
+        if (vib->extentChangeTimer) {
+            if (vib->extentChangeTimer == 1) {
+                vib->extent = (s32)subVib->vibratoExtentTarget;
+            } else {
+                vib->extent += ((s32)subVib->vibratoExtentTarget - vib->extent) / (s32)vib->extentChangeTimer;
+            }
+
+            vib->extentChangeTimer--;
+        } else if (subVib->vibratoExtentTarget != (s32)vib->extent) {
+            if ((vib->extentChangeTimer = subVib->vibratoExtentChangeDelay) == 0) {
+                vib->extent = (s32)subVib->vibratoExtentTarget;
+            }
+        }
+
+        if (vib->rateChangeTimer) {
+            if (vib->rateChangeTimer == 1) {
+                vib->rate = (s32)subVib->vibratoRateTarget;
+            } else {
+                vib->rate += ((s32)subVib->vibratoRateTarget - vib->rate) / (s32)vib->rateChangeTimer;
+            }
+
+            vib->rateChangeTimer--;
+        } else if (subVib->vibratoRateTarget != (s32)vib->rate) {
+            if ((vib->rateChangeTimer = subVib->vibratoRateChangeDelay) == 0) {
+                vib->rate = (s32)subVib->vibratoRateTarget;
+            }
+        }
+    }
+
+    if (vib->extent == 0.0f) {
+        return 1.0f;
+    }
+
+    pitchChange = AudioEffects_GetVibratoPitchChange(vib) + 32768.0f;
+    scaledExtent = vib->extent / 4096.0f;
+    extent = scaledExtent + 1.0f;
+    invExtent = 1.0f / extent;
+
+    // inverse linear interpolation
+    result = 1.0f / ((extent - invExtent) * pitchChange / 65536.0f + invExtent);
+
+    activeVibratoFreqScaleSum += result;
+    activeVibratoCount++;
+
+    return result;
+}
+
+void AudioEffects_NoteVibratoUpdate(Note* note) {
+    if (note->playbackState.portamento.mode != 0) {
+        note->playbackState.portamentoFreqScale = AudioEffects_GetPortamentoFreqScale(&note->playbackState.portamento);
+    }
+    if (note->playbackState.vibratoState.active) {
+        note->playbackState.vibratoFreqScale = AudioEffects_GetVibratoFreqScale(&note->playbackState.vibratoState);
+    }
+}
+
+void AudioEffects_NoteVibratoInit(Note* note) {
+    NotePlaybackState* playbackState = &note->playbackState;
+    VibratoState* vib = &playbackState->vibratoState;
+    VibratoSubStruct* subVib;
+
+    vib->active = true;
+    vib->curve = gWaveSamples[2];
+
+    if (playbackState->parentLayer->unk_0A.s.bit_3 == 1) {
+        vib->vibSubStruct = &playbackState->parentLayer->channel->vibrato;
+    } else {
+        vib->vibSubStruct = &playbackState->parentLayer->vibrato;
+    }
+
+    subVib = vib->vibSubStruct;
+
+    if ((vib->extentChangeTimer = subVib->vibratoExtentChangeDelay) == 0) {
+        vib->extent = (s32)subVib->vibratoExtentTarget;
+    } else {
+        vib->extent = (s32)subVib->vibratoExtentStart;
+    }
+
+    if ((vib->rateChangeTimer = subVib->vibratoRateChangeDelay) == 0) {
+        vib->rate = (s32)subVib->vibratoRateTarget;
+    } else {
+        vib->rate = (s32)subVib->vibratoRateStart;
+    }
+
+    playbackState->vibratoFreqScale = 1.0f;
+    vib->time = 0;
+    vib->delay = subVib->vibratoDelay;
+}
+
+void AudioEffects_NotePortamentoInit(Note* note) {
+    note->playbackState.portamentoFreqScale = 1.0f;
+    note->playbackState.portamento = note->playbackState.parentLayer->portamento;
+}
+
+void AudioEffects_AdsrInit(AdsrState* adsr, AdsrEnvelope* envelope, s16* volOut) {
+    adsr->action.asByte = 0;
+    adsr->delay = 0;
+    adsr->envelope = envelope;
+    adsr->sustain = 0.0f;
+    adsr->current = 0.0f;
+    adsr->velocity = 0.0f;
+    // (An older versions of the audio engine used in Super Mario 64 did
+    // adsr->volOut = volOut. That line and associated struct member were
+    // removed, but the function parameter was forgotten and remains.)
+}
+
+f32 AudioEffects_AdsrUpdate(AdsrState* adsr) {
+    u8 state = adsr->action.s.state;
+
+    switch (state) {
+        case ADSR_STATE_DISABLED:
+            return 0.0f;
+
+        case ADSR_STATE_INITIAL:
+            if (adsr->action.s.hang) {
+                adsr->action.s.state = ADSR_STATE_HANG;
+                break;
+            }
+            // fallthrough
+
+        case ADSR_STATE_START_LOOP:
+            adsr->envIndex = 0;
+            adsr->action.s.state = ADSR_STATE_LOOP;
+            // fallthrough
+
+        retry:
+        case ADSR_STATE_LOOP:
+            adsr->delay = adsr->envelope[adsr->envIndex].delay;
+            switch (adsr->delay) {
+                case ADSR_DISABLE:
+                    adsr->action.s.state = ADSR_STATE_DISABLED;
+                    break;
+                case ADSR_HANG:
+                    adsr->action.s.state = ADSR_STATE_HANG;
+                    break;
+                case ADSR_GOTO:
+                    adsr->envIndex = adsr->envelope[adsr->envIndex].arg;
+                    goto retry;
+                case ADSR_RESTART:
+                    adsr->action.s.state = ADSR_STATE_INITIAL;
+                    break;
+
+                default:
+                    adsr->delay *= gAudioContext.audioBufferParameters.unk_24;
+                    if (adsr->delay == 0) {
+                        adsr->delay = 1;
+                    }
+                    adsr->target = adsr->envelope[adsr->envIndex].arg / 32767.0f;
+                    adsr->target = adsr->target * adsr->target;
+                    adsr->velocity = (adsr->target - adsr->current) / adsr->delay;
+                    adsr->action.s.state = ADSR_STATE_FADE;
+                    adsr->envIndex++;
+                    break;
+            }
+            if (adsr->action.s.state != ADSR_STATE_FADE) {
+                break;
+            }
+            // fallthrough
+
+        case ADSR_STATE_FADE:
+            adsr->current += adsr->velocity;
+            if (--adsr->delay <= 0) {
+                adsr->action.s.state = ADSR_STATE_LOOP;
+            }
+            // fallthrough
+
+        case ADSR_STATE_HANG:
+            break;
+
+        case ADSR_STATE_DECAY:
+        case ADSR_STATE_RELEASE:
+            adsr->current -= adsr->fadeOutVel;
+            if (adsr->sustain != 0.0f && state == ADSR_STATE_DECAY) {
+                if (adsr->current < adsr->sustain) {
+                    adsr->current = adsr->sustain;
+                    adsr->delay = 128;
+                    adsr->action.s.state = ADSR_STATE_SUSTAIN;
+                }
+                break;
+            }
+
+            if (adsr->current < 0.00001f) {
+                adsr->current = 0.0f;
+                adsr->action.s.state = ADSR_STATE_DISABLED;
+            }
+            break;
+
+        case ADSR_STATE_SUSTAIN:
+            adsr->delay--;
+            if (adsr->delay == 0) {
+                adsr->action.s.state = ADSR_STATE_RELEASE;
+            }
+            break;
+    }
+
+    if (adsr->action.s.decay) {
+        adsr->action.s.state = ADSR_STATE_DECAY;
+        adsr->action.s.decay = false;
+    }
+
+    if (adsr->action.s.release) {
+        adsr->action.s.state = ADSR_STATE_RELEASE;
+        adsr->action.s.release = false;
+    }
+
+    if (adsr->current < 0.0f) {
+        return 0.0f;
+    }
+
+    if (adsr->current > 1.0f) {
+        return 1.0f;
+    }
+
+    return adsr->current;
+}
diff --git a/src/code/audio/audio_seqplayer.c b/src/code/audio/audio_seqplayer.c
index e3841a50a..ec4375796 100644
--- a/src/code/audio/audio_seqplayer.c
+++ b/src/code/audio/audio_seqplayer.c
@@ -22,7 +22,7 @@
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/audio_seqplayer/func_80197D24.s")
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/audio_seqplayer/func_80197D4C.s")
+#pragma GLOBAL_ASM("asm/non_matchings/code/audio_seqplayer/AudioSeq_SequencePlayerDisable.s")
 
 #pragma GLOBAL_ASM("asm/non_matchings/code/audio_seqplayer/func_80197E08.s")