From 010f7d12f48f8e046dcda4a5e39221265554e2ff Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Thu, 13 Nov 2008 05:48:38 -0800
Subject: [PATCH] Don't ramp gains when starting a sound from the beginning

---
 Alc/ALu.c                   | 20 +++++++++++++++++---
 OpenAL32/Include/alSource.h |  1 +
 OpenAL32/alSource.c         |  2 ++
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/Alc/ALu.c b/Alc/ALu.c
index 5371d3b5..fbf5a128 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -732,9 +732,23 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
                     WetSend = &ALSource->WetGain;
 
                     //Compute the gain steps for each output channel
-                    for(i = 0;i < OUTPUTCHANNELS;i++)
-                        dryGainStep[i] = (newDrySend[i]-DrySend[i]) / rampLength;
-                    wetGainStep = (newWetSend-(*WetSend)) / rampLength;
+                    if(ALSource->FirstStart && DataPosInt == 0 && DataPosFrac == 0)
+                    {
+                        for(i = 0;i < OUTPUTCHANNELS;i++)
+                        {
+                            DrySend[i] = newDrySend[i];
+                            dryGainStep[i] = 0;
+                        }
+                        *WetSend = newWetSend;
+                        wetGainStep = 0;
+                    }
+                    else
+                    {
+                        for(i = 0;i < OUTPUTCHANNELS;i++)
+                            dryGainStep[i] = (newDrySend[i]-DrySend[i]) / rampLength;
+                        wetGainStep = (newWetSend-(*WetSend)) / rampLength;
+                    }
+                    ALSource->FirstStart = AL_FALSE;
 
                     //Compute 18.14 fixed point step
                     if(Pitch > (float)MAX_PITCH)
diff --git a/OpenAL32/Include/alSource.h b/OpenAL32/Include/alSource.h
index 2bd1db08..617dc4e3 100644
--- a/OpenAL32/Include/alSource.h
+++ b/OpenAL32/Include/alSource.h
@@ -96,6 +96,7 @@ typedef struct ALsource
     // Current gains, which are ramped while mixed
     ALfloat DryGains[OUTPUTCHANNELS];
     ALfloat WetGain;
+    ALboolean FirstStart;
 
     struct ALsource *next;
 } ALsource;
diff --git a/OpenAL32/alSource.c b/OpenAL32/alSource.c
index 50217783..e130e044 100644
--- a/OpenAL32/alSource.c
+++ b/OpenAL32/alSource.c
@@ -1435,6 +1435,7 @@ ALAPI ALvoid ALAPIENTRY alSourcePlayv(ALsizei n, const ALuint *pSourceList)
                             pSource->position = 0;
                             pSource->position_fraction = 0;
                             pSource->BuffersPlayed = 0;
+                            pSource->FirstStart = AL_TRUE;
 
                             pSource->ulBufferID = pSource->queue->buffer;
 
@@ -1451,6 +1452,7 @@ ALAPI ALvoid ALAPIENTRY alSourcePlayv(ALsizei n, const ALuint *pSourceList)
                             pSource->state = AL_PLAYING;
                             pSource->inuse = AL_TRUE;
                             pSource->play = AL_TRUE;
+                            pSource->FirstStart = AL_FALSE;
                         }
 
                         // Check if an Offset has been set
-- 
2.11.4.GIT