Ramp channel gains to remove pops and clicks from abrupt changes

Thanks to Christopher Fitzgerald for helping me work on it

2 files changed, 20 insertions, 0 deletions

diff --git a/OpenAL32/Include/alSource.h b/OpenAL32/Include/alSource.h
index 73b02609..42a1b915 100644
--- a/OpenAL32/Include/alSource.h
+++ b/OpenAL32/Include/alSource.h
@@ -7,6 +7,7 @@
 #define MAX_SENDS                 1
 
 #include "alFilter.h"
+#include "alu.h"
 #include "AL/al.h"
 
 #define AL_DIRECT_FILTER                                   0x20005
@@ -94,6 +95,12 @@ typedef struct ALsource
     // Source Type (Static, Streaming, or Undetermined)
     ALint  lSourceType;
 
+    // Current gains, which are ramped while mixed
+    ALfloat DryGains[OUTPUTCHANNELS];
+    ALfloat WetGains[OUTPUTCHANNELS];
+    ALfloat DryGainHF;
+    ALfloat WetGainHF;
+
     struct ALsource *next;
 } ALsource;
 
diff --git a/OpenAL32/Include/alu.h b/OpenAL32/Include/alu.h
index 6fab1fae..b14180b2 100644
--- a/OpenAL32/Include/alu.h
+++ b/OpenAL32/Include/alu.h
@@ -8,6 +8,19 @@
 extern "C" {
 #endif
 
+enum {
+    FRONT_LEFT = 0,
+    FRONT_RIGHT,
+    SIDE_LEFT,
+    SIDE_RIGHT,
+    BACK_LEFT,
+    BACK_RIGHT,
+    CENTER,
+    LFE,
+
+    OUTPUTCHANNELS
+};
+
 extern ALboolean DuplicateStereo;
 
 __inline ALuint aluBytesFromFormat(ALenum format);