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-rw-r--r--Alc/effects/pshifter.c31
1 files changed, 20 insertions, 11 deletions
diff --git a/Alc/effects/pshifter.c b/Alc/effects/pshifter.c
index 4597da6b..33c3e121 100644
--- a/Alc/effects/pshifter.c
+++ b/Alc/effects/pshifter.c
@@ -66,7 +66,6 @@ typedef struct ALpshifterState {
ALfloat LastPhase[STFT_HALF_SIZE+1];
ALfloat SumPhase[STFT_HALF_SIZE+1];
ALfloat OutputAccum[STFT_SIZE];
- ALfloat window[STFT_SIZE];
ALcomplex FFTbuffer[STFT_SIZE];
@@ -89,6 +88,23 @@ DECLARE_DEFAULT_ALLOCATORS(ALpshifterState)
DEFINE_ALEFFECTSTATE_VTABLE(ALpshifterState);
+/* Define a Hanning window, used to filter the STFT input and output. */
+alignas(16) static ALfloat HanningWindow[STFT_SIZE];
+
+static void InitHanningWindow(void)
+{
+ ALsizei i;
+
+ /* Create lookup table of the Hanning window for the desired size, i.e. STFT_SIZE */
+ for(i = 0;i < STFT_SIZE>>1;i++)
+ {
+ ALdouble val = 1.0 - cos((ALdouble)i / (ALdouble)(STFT_SIZE-1) * (M_PI*2.0));
+ HanningWindow[i] = HanningWindow[STFT_SIZE-(i+1)] = (ALfloat)val * 0.5f;
+ }
+}
+static alonce_flag HanningInitOnce = AL_ONCE_FLAG_INIT;
+
+
/* Converts ALcomplex to ALphasor*/
static inline ALphasor rect2polar( ALcomplex number )
{
@@ -203,17 +219,10 @@ static inline ALvoid FFT(ALcomplex *FFTBuffer, ALsizei FFTSize, ALfloat Sign)
static void ALpshifterState_Construct(ALpshifterState *state)
{
- ALsizei i;
-
ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
SET_VTABLE2(ALpshifterState, ALeffectState, state);
- /* Create lockup table of the Hann window for the desired size, i.e. STFT_size */
- for ( i = 0; i < STFT_SIZE>>1 ; i++ )
- {
- state->window[i] = state->window[STFT_SIZE-(i+1)]
- = 0.5f * ( 1 - cosf(F_TAU*(ALfloat)i/(ALfloat)(STFT_SIZE-1)));
- }
+ alcall_once(&HanningInitOnce, InitHanningWindow);
}
static ALvoid ALpshifterState_Destruct(ALpshifterState *state)
@@ -285,7 +294,7 @@ static ALvoid ALpshifterState_process(ALpshifterState *state, ALsizei SamplesToD
/* Real signal windowing and store in FFTbuffer */
for(k = 0;k < STFT_SIZE;k++)
{
- state->FFTbuffer[k].Real = state->InFIFO[k] * state->window[k];
+ state->FFTbuffer[k].Real = state->InFIFO[k] * HanningWindow[k];
state->FFTbuffer[k].Imag = 0.0f;
}
@@ -374,7 +383,7 @@ static ALvoid ALpshifterState_process(ALpshifterState *state, ALsizei SamplesToD
/* Windowing and add to output */
for(k = 0;k < STFT_SIZE;k++)
- state->OutputAccum[k] += 2.0f * state->window[k]*state->FFTbuffer[k].Real /
+ state->OutputAccum[k] += 2.0f * HanningWindow[k]*state->FFTbuffer[k].Real /
(STFT_HALF_SIZE * OVERSAMP);
/* Shift accumulator, input & output FIFO */