From 1bfa7609d2b27e6ec5928268856a3496723bdeef Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Sat, 16 May 2009 23:34:26 -0700
Subject: [PATCH] Make the filter functions global inline, and use it for echo

---
 Alc/ALu.c                   | 33 ---------------------------------
 Alc/alcEcho.c               |  9 +--------
 OpenAL32/Include/alFilter.h | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 41 deletions(-)

diff --git a/Alc/ALu.c b/Alc/ALu.c
index 602b29f0..8d4b9c0a 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -140,39 +140,6 @@ __inline ALuint aluChannelsFromFormat(ALenum format)
 }
 
 
-static __inline ALfloat lpFilter4P(FILTER *iir, ALuint offset, ALfloat input)
-{
-    ALfloat *history = &iir->history[offset];
-    ALfloat a = iir->coeff;
-    ALfloat output = input;
-
-    output = output + (history[0]-output)*a;
-    history[0] = output;
-    output = output + (history[1]-output)*a;
-    history[1] = output;
-    output = output + (history[2]-output)*a;
-    history[2] = output;
-    output = output + (history[3]-output)*a;
-    history[3] = output;
-
-    return output;
-}
-
-static __inline ALfloat lpFilter2P(FILTER *iir, ALuint offset, ALfloat input)
-{
-    ALfloat *history = &iir->history[offset];
-    ALfloat a = iir->coeff;
-    ALfloat output = input;
-
-    output = output + (history[0]-output)*a;
-    history[0] = output;
-    output = output + (history[1]-output)*a;
-    history[1] = output;
-
-    return output;
-}
-
-
 static __inline ALshort aluF2S(ALfloat Value)
 {
     ALint i;
diff --git a/Alc/alcEcho.c b/Alc/alcEcho.c
index e518fb21..feede2ba 100644
--- a/Alc/alcEcho.c
+++ b/Alc/alcEcho.c
@@ -144,8 +144,6 @@ ALvoid EchoUpdate(ALCcontext *Context, struct ALeffectslot *Slot, ALeffect *Effe
 
 ALvoid EchoProcess(ALechoState *state, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[OUTPUTCHANNELS])
 {
-    ALfloat *history = state->iirFilter.history;
-    const ALfloat a = state->iirFilter.coeff;
     const ALuint delay = state->BufferLength-1;
     ALuint tap1off = state->Tap[0].offset;
     ALuint tap2off = state->Tap[1].offset;
@@ -156,12 +154,7 @@ ALvoid EchoProcess(ALechoState *state, ALuint SamplesToDo, const ALfloat *Sample
     for(i = 0;i < SamplesToDo;i++)
     {
         // Apply damping
-        samp[0] = state->SampleBuffer[tap2off] + SamplesIn[i];
-
-        samp[0] += (history[0]-samp[0]) * a;
-        history[0] = samp[0];
-        samp[0] += (history[1]-samp[0]) * a;
-        history[1] = samp[0];
+        samp[0] = lpFilter2P(&state->iirFilter, 0, state->SampleBuffer[tap2off]+SamplesIn[i]);
 
         // Apply feedback gain and mix in the new sample
         state->SampleBuffer[fboff] = samp[0] * state->FeedGain;
diff --git a/OpenAL32/Include/alFilter.h b/OpenAL32/Include/alFilter.h
index 40fff4fd..c0a05d6a 100644
--- a/OpenAL32/Include/alFilter.h
+++ b/OpenAL32/Include/alFilter.h
@@ -13,6 +13,39 @@ typedef struct {
     ALfloat history[0];
 } FILTER;
 
+static __inline ALfloat lpFilter4P(FILTER *iir, ALuint offset, ALfloat input)
+{
+    ALfloat *history = &iir->history[offset];
+    ALfloat a = iir->coeff;
+    ALfloat output = input;
+
+    output = output + (history[0]-output)*a;
+    history[0] = output;
+    output = output + (history[1]-output)*a;
+    history[1] = output;
+    output = output + (history[2]-output)*a;
+    history[2] = output;
+    output = output + (history[3]-output)*a;
+    history[3] = output;
+
+    return output;
+}
+
+static __inline ALfloat lpFilter2P(FILTER *iir, ALuint offset, ALfloat input)
+{
+    ALfloat *history = &iir->history[offset];
+    ALfloat a = iir->coeff;
+    ALfloat output = input;
+
+    output = output + (history[0]-output)*a;
+    history[0] = output;
+    output = output + (history[1]-output)*a;
+    history[1] = output;
+
+    return output;
+}
+
+
 #define AL_FILTER_TYPE                                     0x8001
 
 #define AL_FILTER_NULL                                     0x0000
-- 
2.11.4.GIT