From febedc3a389a88e29ee0237a87b6dee3dfbdec2f Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Sun, 21 Apr 2024 16:32:45 -0700
Subject: [PATCH] Util: Allow audio resampler to use different interpolators

---
 include/mgba-util/audio-resampler.h |  9 +++++++--
 include/mgba-util/interpolator.h    |  5 +++++
 src/util/audio-resampler.c          | 29 +++++++++++++++++++++++------
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/include/mgba-util/audio-resampler.h b/include/mgba-util/audio-resampler.h
index 50f298930..e1ec3d84c 100644
--- a/include/mgba-util/audio-resampler.h
+++ b/include/mgba-util/audio-resampler.h
@@ -21,11 +21,16 @@ struct mAudioResampler {
 	double timestamp;
 	double lowWaterMark;
 	double highWaterMark;
-	struct mInterpolatorSinc interp;
+	enum mInterpolatorType interpType;
+	union {
+		struct mInterpolator interp;
+		struct mInterpolatorSinc sinc;
+		struct mInterpolatorCosine cosine;
+	};
 	bool consume;
 };
 
-void mAudioResamplerInit(struct mAudioResampler*);
+void mAudioResamplerInit(struct mAudioResampler*, enum mInterpolatorType);
 void mAudioResamplerDeinit(struct mAudioResampler*);
 void mAudioResamplerSetSource(struct mAudioResampler*, struct mAudioBuffer* source, double rate, bool consume);
 void mAudioResamplerSetDestination(struct mAudioResampler*, struct mAudioBuffer* destination, double rate);
diff --git a/include/mgba-util/interpolator.h b/include/mgba-util/interpolator.h
index 538115c37..b7a59acd5 100644
--- a/include/mgba-util/interpolator.h
+++ b/include/mgba-util/interpolator.h
@@ -10,6 +10,11 @@
 
 CXX_GUARD_START
 
+enum mInterpolatorType {
+	mINTERPOLATOR_SINC,
+	mINTERPOLATOR_COSINE,
+};
+
 struct mInterpolationData {
 	int16_t (*at)(int index, const void* context);
 	void* context;
diff --git a/src/util/audio-resampler.c b/src/util/audio-resampler.c
index 0f0147c34..5b7a069e4 100644
--- a/src/util/audio-resampler.c
+++ b/src/util/audio-resampler.c
@@ -22,15 +22,32 @@ static int16_t _sampleAt(int index, const void* context) {
 	return mAudioBufferPeek(data->resampler->source, data->channel, index);
 }
 
-void mAudioResamplerInit(struct mAudioResampler* resampler) {
+void mAudioResamplerInit(struct mAudioResampler* resampler, enum mInterpolatorType interpType) {
 	memset(resampler, 0, sizeof(*resampler));
-	mInterpolatorSincInit(&resampler->interp, 0, 0);
-	resampler->lowWaterMark = resampler->interp.width;
-	resampler->highWaterMark = 0;
+	resampler->interpType = interpType;
+	switch (interpType) {
+	case mINTERPOLATOR_SINC:
+		mInterpolatorSincInit(&resampler->sinc, 0, 0);
+		resampler->lowWaterMark = resampler->sinc.width;
+		resampler->highWaterMark = resampler->sinc.width;
+		break;
+	case mINTERPOLATOR_COSINE:
+		mInterpolatorCosineInit(&resampler->cosine, 0);
+		resampler->lowWaterMark = 0;
+		resampler->highWaterMark = 1;
+		break;
+	}
 }
 
 void mAudioResamplerDeinit(struct mAudioResampler* resampler) {
-	mInterpolatorSincDeinit(&resampler->interp);
+	switch (resampler->interpType) {
+	case mINTERPOLATOR_SINC:
+		mInterpolatorSincDeinit(&resampler->sinc);
+		break;
+	case mINTERPOLATOR_COSINE:
+		mInterpolatorCosineDeinit(&resampler->cosine);
+		break;
+	}
 	resampler->source = NULL;
 	resampler->destination = NULL;
 }
@@ -50,7 +67,7 @@ size_t mAudioResamplerProcess(struct mAudioResampler* resampler) {
 	int16_t sampleBuffer[MAX_CHANNELS] = {0};
 	double timestep = resampler->sourceRate / resampler->destRate;
 	double timestamp = resampler->timestamp;
-	struct mInterpolator* interp = &resampler->interp.d;
+	struct mInterpolator* interp = &resampler->interp;
 	struct mAudioResamplerData context = {
 		.resampler = resampler,
 	};