Use a minimum phase HRTF data set

This reduces the coefficient size from 128 down to 32, with a set of delays

3 files changed, 20 insertions, 10 deletions

diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index b6986a07..8df5a4b9 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -567,10 +567,11 @@ const ALCchar *DevFmtChannelsString(enum DevFmtChannels chans);
 ALboolean IsValidType(ALenum type);
 ALboolean IsValidChannels(ALenum type);
 
-#define HRTF_BITS        (7)
-#define HRTF_LENGTH      (1<<HRTF_BITS)
-#define HRTF_LENGTH_MASK (HRTF_LENGTH-1)
-void GetHrtfCoeffs(ALfloat elevation, ALfloat angle, const ALshort **left, const ALshort **right);
+#define HRIR_BITS        (5)
+#define HRIR_LENGTH      (1<<HRIR_BITS)
+#define HRIR_LENGTH_MASK (HRIR_LENGTH-1)
+void InitHrtf(void);
+void GetHrtfCoeffs(ALfloat elevation, ALfloat angle, const ALshort **left, const ALshort **right, ALuint *ldelay, ALuint *rdelay);
 
 void al_print(const char *fname, unsigned int line, const char *fmt, ...)
              PRINTF_STYLE(3,4);
diff --git a/OpenAL32/Include/alSource.h b/OpenAL32/Include/alSource.h
index 53d7f53c..0572cbc1 100644
--- a/OpenAL32/Include/alSource.h
+++ b/OpenAL32/Include/alSource.h
@@ -11,6 +11,10 @@
 extern "C" {
 #endif
 
+#define SRC_HISTORY_BITS   (7)
+#define SRC_HISTORY_LENGTH (1<<SRC_HISTORY_BITS)
+#define SRC_HISTORY_MASK   (SRC_HISTORY_LENGTH-1)
+
 typedef enum {
     POINT_RESAMPLER = 0,
     LINEAR_RESAMPLER,
@@ -90,20 +94,21 @@ typedef struct ALsource
     ALuint SampleSize;
 
     /* HRTF info */
-    ALfloat HrtfHistory[MAXCHANNELS][HRTF_LENGTH];
+    ALfloat HrtfHistory[MAXCHANNELS][SRC_HISTORY_LENGTH][2];
     ALuint HrtfOffset;
 
-    // Current target parameters used for mixing
-    ALboolean NeedsUpdate;
+    /* Current target parameters used for mixing */
     struct {
         ALint Step;
 
-        ALfloat HrtfCoeffs[MAXCHANNELS][HRTF_LENGTH][2];
+        ALfloat HrtfCoeffs[MAXCHANNELS][HRIR_LENGTH][2];
+        ALuint HrtfDelay[MAXCHANNELS][2];
 
         /* A mixing matrix. First subscript is the channel number of the input
          * data (regardless of channel configuration) and the second is the
          * channel target (eg. FRONT_LEFT) */
         ALfloat DryGains[MAXCHANNELS][MAXCHANNELS];
+
         FILTER iirFilter;
         ALfloat history[MAXCHANNELS*2];
 
@@ -113,6 +118,7 @@ typedef struct ALsource
             ALfloat history[MAXCHANNELS];
         } Send[MAX_SENDS];
     } Params;
+    ALboolean NeedsUpdate;
 
     ALvoid (*Update)(struct ALsource *self, const ALCcontext *context);
     ALvoid (*DoMix)(struct ALsource *self, ALCdevice *Device,
diff --git a/OpenAL32/alSource.c b/OpenAL32/alSource.c
index 6c6bf44b..7dc4a2a9 100644
--- a/OpenAL32/alSource.c
+++ b/OpenAL32/alSource.c
@@ -1355,8 +1355,11 @@ AL_API ALvoid AL_APIENTRY alSourcePlayv(ALsizei n, const ALuint *sources)
             for(j = 0;j < MAXCHANNELS;j++)
             {
                 ALuint k;
-                for(k = 0;k < HRTF_LENGTH;k++)
-                    Source->HrtfHistory[j][k] = 0.0f;
+                for(k = 0;k < SRC_HISTORY_LENGTH;k++)
+                {
+                    Source->HrtfHistory[j][k][0] = 0.0f;
+                    Source->HrtfHistory[j][k][1] = 0.0f;
+                }
             }
             Source->HrtfOffset = 0;
         }