From 8be50e7844ccc8a9fce263127978fb3017f0f60d Mon Sep 17 00:00:00 2001
From: Xerbo <xerbo@protonmail.com>
Date: Tue, 20 Sep 2022 19:12:46 +0100
Subject: [PATCH] Readd apt_image_t::zenith and MSVC complex #20

---
 src/apt.h  |  1 +
 src/dsp.c  | 21 ++++++++++++++++++---
 src/main.c |  4 ++--
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/apt.h b/src/apt.h
index a7998e5..2478e9e 100644
--- a/src/apt.h
+++ b/src/apt.h
@@ -81,6 +81,7 @@ typedef int (*apt_getsamples_t)(void *context, float *samples, int count);
 typedef struct {
 	float *prow[APT_MAX_HEIGHT]; // Row buffers
 	int nrow; // Number of rows
+	int zenith; // Row in image where satellite reaches peak elevation
 	apt_channel_t chA, chB; // ID of each channel
 	char name[256]; // Stripped filename
 	char *palette; // Filename of palette
diff --git a/src/dsp.c b/src/dsp.c
index 5821095..47afe64 100755
--- a/src/dsp.c
+++ b/src/dsp.c
@@ -26,6 +26,12 @@
 #include "taps.h"
 #include "util.h"
 
+#ifdef _MSC_VER
+typedef _Fcomplex complexf_t;
+#else
+typedef complex float complexf_t;
+#endif
+
 // Block sizes
 #define BLKAMP 32768
 #define BLKIN 32768
@@ -59,11 +65,11 @@ int apt_init(double sample_rate) {
 	return 0;
 }
 
-static float pll(float complex in) {
+static float pll(complexf_t in) {
 	static float oscillator_phase = 0.0;
 
 	// Internal oscillator
-	float complex osc = cos(oscillator_phase) + -sin(oscillator_phase)*I;
+	complexf_t osc = cos(oscillator_phase) + -sin(oscillator_phase)*I;
 	in *= osc;
 
 	// Error detector
@@ -104,7 +110,7 @@ static int getamp(float *ampbuff, int count, apt_getsamples_t getsamples, void *
 		}
 
 		// Process read samples into a brightness value
-		float complex sample = hilbert_transform(&inbuff[idxin], hilbert_filter, HILBERT_FILTER_SIZE);
+		complexf_t sample = hilbert_transform(&inbuff[idxin], hilbert_filter, HILBERT_FILTER_SIZE);
 		ampbuff[n] = pll(sample);
 
 		// Increment current sample
@@ -159,6 +165,7 @@ int apt_getpixelrow(float *pixelv, int nrow, int *zenith, int reset, apt_getsamp
 	static size_t npv;
 	static int synced = 0;
 	static float max = 0.0;
+	static float minDoppler = 1000000000, previous = 0;
 
 	if(reset) synced = 0;
 
@@ -182,6 +189,14 @@ int apt_getpixelrow(float *pixelv, int nrow, int *zenith, int reset, apt_getsamp
 	corr = convolve(&pixelv[1], sync_pattern, SYNC_PATTERN_SIZE - 1);
 	lcorr = convolve(&pixelv[2], sync_pattern, SYNC_PATTERN_SIZE - 2);
 	FreqLine = 1.0+((ecorr-lcorr) / corr / APT_IMG_WIDTH / 4.0);
+
+	float val = fabs(lcorr - ecorr)*0.25 + previous*0.75;
+	if(val < minDoppler && nrow > 10){
+		minDoppler = val;
+		*zenith = nrow;
+	}
+	previous = fabs(lcorr - ecorr);
+
 	// The point in which the pixel offset is recalculated
 	if (corr < 0.75 * max) {
 		synced = 0;
diff --git a/src/main.c b/src/main.c
index 0701c5a..51d91a4 100644
--- a/src/main.c
+++ b/src/main.c
@@ -172,7 +172,7 @@ static int processAudio(char *filename, options_t *opts){
 			img.prow[img.nrow] = (float *) malloc(sizeof(float) * APT_PROW_WIDTH);
 
 			// Write into memory and break the loop when there are no more samples to read
-			if (apt_getpixelrow(img.prow[img.nrow], img.nrow, NULL, (img.nrow == 0), getsamples, NULL) == 0)
+			if (apt_getpixelrow(img.prow[img.nrow], img.nrow, &img.zenith, (img.nrow == 0), getsamples, NULL) == 0)
 				break;
 
 			if(opts->realtime) pushRow(img.prow[img.nrow], APT_IMG_WIDTH);
@@ -197,7 +197,7 @@ static int processAudio(char *filename, options_t *opts){
 
 	// Crop noise from start and end of image
 	if(CONTAINS(opts->effects, Crop_Noise)){
-		apt_cropNoise(&img);
+		img.zenith -= apt_cropNoise(&img);
 	}
 
 	// Denoise