From 863aa2235c10901d746b0c7ff571ea9ac8a54a60 Mon Sep 17 00:00:00 2001
From: gheskett <gheskett@gmail.com>
Date: Tue, 3 Aug 2021 05:15:56 -0500
Subject: [PATCH] reverb bugfix

---
 src/audio/heap.c      | 12 ++++++------
 src/audio/synthesis.c | 24 ++++++++++++++----------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/src/audio/heap.c b/src/audio/heap.c
index cd67754b..6d5be82c 100644
--- a/src/audio/heap.c
+++ b/src/audio/heap.c
@@ -1232,10 +1232,10 @@ void audio_reset_session(void) {
     gSamplesPerFrameTarget = ALIGN16(gAiFrequency / 60);
     gReverbDownsampleRate = preset->reverbDownsampleRate;
 #ifdef BETTER_REVERB
-    if (gIsConsole)
-        reverbConsole = betterReverbConsoleDownsample;
+    if (IO_READ(DPC_PIPEBUSY_REG) == 0)
+        reverbConsole = 2; // Setting this to 1 will crash unless you increase the better reverb buffer (in which case it will just freeze instead)
     else
-        reverbConsole = 2;
+        reverbConsole = betterReverbConsoleDownsample; // Console!
 
     if (reverbConsole <= 0) {
         reverbConsole = 1;
@@ -1245,9 +1245,9 @@ void audio_reset_session(void) {
         consoleBetterReverb = TRUE;
     }
     
-    if (gReverbDownsampleRate < reverbConsole)
-        gReverbDownsampleRate = reverbConsole;
-    reverbWindowSize /= (1 << (gReverbDownsampleRate - 1));
+    if (gReverbDownsampleRate < (1 << (reverbConsole - 1)))
+        gReverbDownsampleRate = (1 << (reverbConsole - 1));
+    reverbWindowSize /= gReverbDownsampleRate;
 #endif
 
     switch (gReverbDownsampleRate) {
diff --git a/src/audio/synthesis.c b/src/audio/synthesis.c
index 029b1ad7..3051deb9 100644
--- a/src/audio/synthesis.c
+++ b/src/audio/synthesis.c
@@ -46,15 +46,15 @@ struct VolumeChange {
 
 /* ----------------------------------------------------------REVERB PARAMETERS----------------------------------------------------------------- */
 
-s16 *lastSamplePtrL;
-s16 *lastSamplePtrR;
+s32 gReverbRevIndex = 0x9A; // Affects decay time mostly; can be messed with at any time
+s32 gReverbGainIndex = 0xA6; // Affects signal retransmitted back into buffers; can be messed with at any time
+s32 gReverbWetSignal = 0xF3; // Amount of reverb specific output in final signal; can be messed with at any time
+s32 gReverbDrySignal = 0x26; // Amount of original input in final signal (large values can cause terrible feedback!); can be messed with at any time
 
-s32 gReverbRevIndex = 0x9A; // Affects decay time mostly; can be messed with
-s32 gReverbGainIndex = 0xA6; // Affects signal retransmitted back into buffers; can be messed with
-s32 gReverbWetSignal = 0xF3; // Amount of reverb specific output in final signal; can be messed with
-s32 gReverbDrySignal = 0x26; // Amount of original input in final signal (large values can cause terrible feedback!); can be messed with
-
-u32 delays[NUM_ALLPASS] = { // These values affect reverb delays, bigger values result in fatter echo (and more memory); can be messed with, but must be cumulatively smaller than BETTER_REVERB_SIZE/8
+// These values affect reverb delays, bigger values result in fatter echo (and more memory); can be messed with, but must be cumulatively smaller than BETTER_REVERB_SIZE/8.
+// If setting reverb downsample value to 1 (which currently does not work anyway), this must be BETTER_REVERB_SIZE/16.
+// These values should never be changed
+u32 delays[NUM_ALLPASS] = {
     1080, 1352, 1200,
     1384, 1048, 1352,
     1200, 1232, 1432,
@@ -77,8 +77,12 @@ u32 allpassIdx[2][NUM_ALLPASS] = {
 s32 tmpBuf[NUM_ALLPASS] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 s32 ***delayBufs;
 
-u8 consoleBetterReverb = TRUE;
-s8 betterReverbConsoleDownsample = 3; // Set this to 4 if game is running too slow; set this to -1 to vanilla reverb on console only
+u8 consoleBetterReverb = TRUE; // Do not change this line unless you know what you're doing; Please use the variable below instead.
+
+// Setting this to 4 completely breaks game sound, so set this value to -1 to use vanilla reverb for console if this is too slow.
+// You can change this value back and forth before audio_reset_session is called if different levels can tolerate the demand better than others.
+// A higher downsample value hits the game's frequency limit sooner, which may cause the reverb to be off pitch. This is a vanilla level issue (and counter intuitive).
+s8 betterReverbConsoleDownsample = 3;
 
 /* --------------------------------------------------------END REVERB PARAMETERS--------------------------------------------------------------- */