comb filter.

Author: tortugaveloz

src/audio/effects.c

@@ -551,8 +551,6 @@ s32 adsr_update(struct AdsrState *adsr) {
  *   -32 to -1 (0xE0-0xFF): Sound is below camera (negative Y)
  *   0 to 127: Sound is above camera (positive Y)
  *   Bit 0 is always set (odd number)
- *
- * Based on Majora's Mask AudioSfx_ComputeCombFilter.
  */
 s8 audio_compute_comb_filter(f32 posY) {
     s8 combFilterGain;

src/audio/external.c

@@ -1273,7 +1273,7 @@ static void update_game_sound(void) {
                         // Set comb filter gain based on Y height for vertical positioning
                         gSequencePlayers[SEQ_PLAYER_SFX].channels[channelIndex]->combFilterGain =
                             audio_compute_comb_filter(*sSoundBanks[bank][soundIndex].y);
-                        gSequencePlayers[SEQ_PLAYER_SFX].channels[channelIndex]->combFilterSize = 0x28;
+                        gSequencePlayers[SEQ_PLAYER_SFX].channels[channelIndex]->combFilterSize = 16;
                     }
 
                     switch (bank) {

src/audio/internal.h

@@ -447,8 +447,8 @@ struct SequenceChannel {
 #endif
     /*0x05, 0x06*/ u8 bankId;
     /*          */ u8 surroundEffectIndex; // Surround depth: 0 = front, 0x7F = behind
-    /*          */ s8 combFilterGain;      // Comb filter gain for surround height effect (-32 to 127)
     /*          */ u8 combFilterSize;      // Comb filter size (delay in bytes, typically 0x28)
+    /*          */ u16 combFilterGain;     // Comb filter gain for surround height effect
 #if defined(VERSION_EU) || defined(VERSION_SH)
     /*    , 0x07*/ u8 reverbIndex;
     /*    , 0x08, 0x09*/ u8 bookOffset;
@@ -647,8 +647,8 @@ struct Note {
     /*      0x32, 0x32*/ u8 sampleCountIndex;
     /*                */ u8 surroundEffectIndex; // Index for surround effect pan position
     /*                */ u8 pan;                 // Pan position: 0 = left, 128 = center, 255 = right
-    /*                */ s8 combFilterGain;      // Comb filter gain for surround height effect
     /*                */ u8 combFilterSize;      // Comb filter size (delay in bytes)
+    /*                */ u16 combFilterGain;     // Comb filter gain for surround height effect
 #ifdef VERSION_SH
     /*            0x33*/ u8 bankId;
     /*            0x34*/ u8 unkSH34;
@@ -711,9 +711,9 @@ struct Note {
     /*0x40*/ u8 reverbVol; // Q1.7
     /*0x41*/ u8 surroundEffectIndex; // Index for surround effect pan position
     /*0x42*/ u8 pan; // Pan position: 0 = left, 128 = center, 255 = right
-    /*    */ s8 combFilterGain;      // Comb filter gain for surround height effect (-32 to 127)
     /*    */ u8 combFilterSize;      // Comb filter size (delay in bytes, typically 0x28)
     /*    */ u8 combFilterNeedsInit; // TRUE if comb filter state needs to be cleared
+    /*    */ u16 combFilterGain;     // Comb filter gain for surround height effect
     /*0x44*/ struct NoteAttributes attributes;
     /*0x54, 0x58*/ struct AdsrState adsr;
     /*0x74, 0x7C*/ struct Portamento portamento;

src/audio/synthesis.c

@@ -1090,7 +1090,6 @@ u64 *synthesis_process_notes(s16 *aiBuf, s32 bufLen, u64 *cmd) {
             }
 #else
             if (note->stereoHeadsetEffects && note->combFilterSize != 0 && note->combFilterGain != 0 && gSoundMode == SOUND_MODE_SURROUND) {
-                printf("combFilterSize: %d, combFilterGain: %d\n", note->combFilterSize, note->combFilterGain);
                 s16 *combFilterState = note->synthesisBuffers->combFilterState;
                 u16 combFilterDmem;
                 // Copy mono signal to comb temp buffer
@@ -1500,7 +1499,6 @@ u64 *note_apply_headset_pan_effects(u64 *cmd, struct Note *note, s32 bufLen, s32
  *   0x40-0x7F: Sound behind (0x40 = at camera, 0x7F = far behind) - more rear effect
  * 
  * This creates a rear channel effect by phase-inverting and mixing based on pan and depth.
- * Based on Majora's Mask Audio_SetSequenceProperties surround calculation.
  */
 u64 *note_apply_surround_effect(u64 *cmd, struct Note *note, s32 bufLen) {
     s16 dryGain;