SceneKit Visualization: Minor vDSP optimization

Gather maximum bands using vDSP, and also align the structure size to 4
floats per step.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Audio/ThirdParty/deadbeef/fft_accelerate.c

@@ -60,19 +60,24 @@ static void
 _init_buffers(int fft_size) {
 	if(fft_size != _fft_size) {
 		fft_free();
+		_fft_size = 0;
 
 		_dftSetup = vDSP_DFT_zrop_CreateSetup(NULL, fft_size * 2, vDSP_DFT_FORWARD);
+		if(!_dftSetup) return;
 
 		_dftBuffer.realp = _memalign_calloc(fft_size, sizeof(Float32), 16);
 		_dftBuffer.imagp = _memalign_calloc(fft_size, sizeof(Float32), 16);
+		if(!_dftBuffer.realp || !_dftBuffer.imagp) return;
 
 		_window = _memalign_calloc(fft_size * 2, sizeof(Float32), 16);
+		if(!_window) return;
 		vDSP_blkman_window(_window, fft_size * 2, 0);
 
 		Float32 normFactor = 2.0f / (fft_size * 2);
 		vDSP_vsmul(_window, 1, &normFactor, _window, 1, fft_size * 2);
 
 		_rawSpectrum = (struct SpectrumData *) _memalign_calloc(sizeof(struct SpectrumData) + sizeof(Float32) * fft_size, 1, 16);
+		if(!_rawSpectrum) return;
 		_rawSpectrum->length = fft_size;
 
 		_fft_size = fft_size;
@@ -80,7 +85,14 @@ _init_buffers(int fft_size) {
 }
 
 void fft_calculate(const float *data, float *freq, int fft_size) {
+	if(!freq || !fft_size) return;
 	_init_buffers(fft_size);
+	if(!_fft_size || !data) {
+		// Decibels
+		float kZeroLevel = -128.0;
+		vDSP_vfill(&kZeroLevel, freq, 1, fft_size);
+		return;
+	}
 
 	// Split the waveform
 	DSPSplitComplex dest = { _dftBuffer.realp, _dftBuffer.imagp };
@@ -111,7 +123,7 @@ void fft_calculate(const float *data, float *freq, int fft_size) {
 	cblas_scopy(fft_size, rawSpectrum, 1, freq, 1);
 }
 
-void fft_free(void) {
+void __attribute__((destructor)) fft_free(void) {
 	free(_dftBuffer.realp);
 	free(_dftBuffer.imagp);
 	free(_window);
@@ -123,4 +135,5 @@ void fft_free(void) {
 	_dftBuffer.imagp = NULL;
 	_window = NULL;
 	_rawSpectrum = NULL;
+	_dftSetup = NULL;
 }

Visualization/SpectrumViewSK.m

@@ -11,6 +11,8 @@
 
 #import <Metal/Metal.h>
 
+#import <Accelerate/Accelerate.h>
+
 #import "analyzer.h"
 
 #import "Logging.h"
@@ -416,16 +418,14 @@ extern NSString *CogPlaybackDidStopNotificiation;
 	for(int i = 0; i < 11; ++i) {
 		float maxValue = 0.0;
 		float maxMax = 0.0;
-		for(int j = 0; j < maxBars; ++j) {
+		{
 			const int barBase = i * barStep;
-			const int barIndex = barBase + j;
+			const int barEnd = (barBase + maxBars) <= _draw_data.bar_count ? (barBase + maxBars) : _draw_data.bar_count;
-			if(barIndex < _draw_data.bar_count) {
+			{
-				if(bar[barIndex].bar_height > maxValue) {
+				const int stride = sizeof(ddb_analyzer_draw_bar_t) / sizeof(Float32);
-					maxValue = bar[barIndex].bar_height;
+				const int barCount = barEnd - barBase + 1;
-				}
+				vDSP_maxv(&bar[barBase].bar_height, stride, &maxValue, barCount);
-				if(bar[barIndex].peak_ypos > maxMax) {
+				vDSP_maxv(&bar[barBase].peak_ypos, stride, &maxMax, barCount);
-					maxMax = bar[barIndex].peak_ypos;
-				}
 			}
 		}
 		SCNNode *node = nodes[i + 1];

Visualization/ThirdParty/deadbeef/analyzer.h

@@ -23,6 +23,8 @@
 #ifndef analyzer_h
 #define analyzer_h
 
+#include <stdint.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -52,6 +54,7 @@ typedef struct {
 	float xpos;
 	float peak_ypos;
 	float bar_height;
+	uint32_t unused;
 } ddb_analyzer_draw_bar_t;
 
 typedef struct {