Implement a 6-point sinc-lanczos filter

3 files changed, 14 insertions, 2 deletions

diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index 7d508721..9703a9cf 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -529,6 +529,7 @@ enum Resampler {
     PointResampler,
     LinearResampler,
     FIR4Resampler,
+    FIR6Resampler,
 
     ResamplerMax,
 };
diff --git a/OpenAL32/Include/alu.h b/OpenAL32/Include/alu.h
index 16b3e1ab..c37ebb9f 100644
--- a/OpenAL32/Include/alu.h
+++ b/OpenAL32/Include/alu.h
@@ -202,7 +202,11 @@ inline ALuint64 clampu64(ALuint64 val, ALuint64 min, ALuint64 max)
 { return minu64(max, maxu64(min, val)); }
 
 
-extern alignas(16) ALfloat ResampleCoeffs[FRACTIONONE][4];
+union ResamplerCoeffs {
+    ALfloat FIR4[FRACTIONONE][4];
+    ALfloat FIR6[FRACTIONONE][6];
+};
+extern alignas(16) union ResamplerCoeffs ResampleCoeffs;
 
 
 inline ALfloat lerp(ALfloat val1, ALfloat val2, ALfloat mu)
@@ -211,9 +215,14 @@ inline ALfloat lerp(ALfloat val1, ALfloat val2, ALfloat mu)
 }
 inline ALfloat resample_fir4(ALfloat val0, ALfloat val1, ALfloat val2, ALfloat val3, ALuint frac)
 {
-    const ALfloat *k = ResampleCoeffs[frac];
+    const ALfloat *k = ResampleCoeffs.FIR4[frac];
     return k[0]*val0 + k[1]*val1 + k[2]*val2 + k[3]*val3;
 }
+inline ALfloat resample_fir6(ALfloat val0, ALfloat val1, ALfloat val2, ALfloat val3, ALfloat val4, ALfloat val5, ALuint frac)
+{
+    const ALfloat *k = ResampleCoeffs.FIR6[frac];
+    return k[0]*val0 + k[1]*val1 + k[2]*val2 + k[3]*val3 + k[4]*val4 + k[5]*val5;
+}
 
 
 void aluInitMixer(void);
diff --git a/OpenAL32/alSource.c b/OpenAL32/alSource.c
index aff82b5f..24e5874d 100644
--- a/OpenAL32/alSource.c
+++ b/OpenAL32/alSource.c
@@ -43,11 +43,13 @@ const ALsizei ResamplerPadding[ResamplerMax] = {
     0, /* Point */
     1, /* Linear */
     2, /* FIR4 */
+    3, /* FIR6 */
 };
 const ALsizei ResamplerPrePadding[ResamplerMax] = {
     0, /* Point */
     0, /* Linear */
     1, /* FIR4 */
+    2, /* FIR6 */
 };