Add support for building a shared library (libaptdec).

Exported functions and types prefixed with apt_
  Callback added for getsample, instead of calling named function.
  Allow library to be built without libpng or libsndfile.
Add support for building with MSVC on Windows.
Fix a few MSVC compiler warnings.
Fix nonlinear radiance correction for NOAA19.

CMakeLists.txt

@@ -2,33 +2,53 @@ cmake_minimum_required (VERSION 3.0.0)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
 
 project(aptdec)
-file(GLOB_RECURSE C_SOURCE_FILES src/*.c src/libs/*.c)
-add_executable(aptdec ${C_SOURCE_FILES})
+
+# libpng
+find_package(PNG)
+
+# libsndfile
+find_package(LibSndFile)
+
+set(LIB_C_SOURCE_FILES src/color.c src/dsp.c src/filter.c src/image.c src/libs/reg.c src/libs/median.c)
+set(EXE_C_SOURCE_FILES src/main.c src/pngio.c src/libs/argparse.c)
+set(LIB_C_HEADER_FILES src/apt.h)
+
+add_library(libaptdec SHARED ${LIB_C_SOURCE_FILES})
 
 add_compile_definitions(PALETTE_DIR="../palettes")
 
-# Math
-target_link_libraries(aptdec PRIVATE m)
+if (PNG_FOUND AND LIBSNDFILE_FOUND)
+    add_executable(aptdec ${EXE_C_SOURCE_FILES})
+    target_link_libraries(aptdec PRIVATE libaptdec)
+    target_link_libraries(aptdec PRIVATE PNG::PNG)
+    target_link_libraries(aptdec PRIVATE ${LIBSNDFILE_LIBRARY})
+    if (CLANG OR GCC)
+        # Math
+        target_link_libraries(aptdec PRIVATE m)
 
-# Throw errors on warnings on release builds
-if(CMAKE_BUILD_TYPE MATCHES "Release")
-    target_compile_options(aptdec PRIVATE -Wall -Wextra -pedantic -Wno-missing-field-initializers -Werror)
+        # Throw errors on warnings on release builds
+        if(CMAKE_BUILD_TYPE MATCHES "Release")
+            target_compile_options(aptdec PRIVATE -Wall -Wextra -pedantic -Wno-missing-field-initializers -Werror)
+        else()
+            target_compile_options(aptdec PRIVATE -Wall -Wextra -pedantic)
+        endif()
+    elseif (MSVC)
+        target_compile_options(aptdec PRIVATE /D_CRT_SECURE_NO_WARNINGS=1)
+    endif()
 else()
-    target_compile_options(aptdec PRIVATE -Wall -Wextra -pedantic)
+    MESSAGE(STATUS "WARNING: Only building libaptdec, as not all of the required libraries were found.")
 endif()
 
-# libpng
-target_link_libraries(aptdec PRIVATE PNG::PNG)
-if(WIN32 AND NOT MINGW)
-    find_package(PNG CONFIG REQUIRED)
-else()
-    find_package(PNG REQUIRED)
+if (CLANG OR CGCC)
+    if(CMAKE_BUILD_TYPE MATCHES "Release")
+        target_compile_options(libaptdec PRIVATE -Wall -Wextra -pedantic -Wno-missing-field-initializers -Werror)
+    else()
+        target_compile_options(libaptdec PRIVATE -Wall -Wextra -pedantic)
+    endif()
+elseif (MSVC)
+    target_compile_options(libaptdec PRIVATE /D_CRT_SECURE_NO_WARNINGS=1)
 endif()
 
-# libsndfile
-find_package(LibSndFile REQUIRED)
-target_link_libraries(aptdec PRIVATE ${LIBSNDFILE_LIBRARY})
-
 # TODO: get this from git
 set(PROJECT_VERSION "1.7.0")
 
@@ -45,16 +65,25 @@ IF(NOT WIN32)
     set(CPACK_GENERATOR "DEB;TGZ")
     set(CPACK_PACKAGE_FILE_NAME "${CPACK_PACKAGE_NAME}-${CPACK_PACKAGE_VERSION}.${CMAKE_SYSTEM_PROCESSOR}")
 
-    install(TARGETS aptdec DESTINATION "bin/")
-    install(DIRECTORY "${PROJECT_SOURCE_DIR}/palettes/" DESTINATION "palettes/")
+    if (TARGET aptdec)
+        install(TARGETS aptdec DESTINATION "bin/")
+        install(DIRECTORY "${PROJECT_SOURCE_DIR}/palettes/" DESTINATION "palettes/")
+    endif()
+
+    install(TARGETS libaptdec LIBRARY DESTINATION lib)
+    install(FILES ${LIB_C_HEADER_FILES} DESTINATION include/apt )
 else()
     #set(CPACK_GENERATOR "ZIP;NSIS")
     set(CPACK_GENERATOR "ZIP")
     set(CPACK_PACKAGE_FILE_NAME "${CPACK_PACKAGE_NAME}-${CPACK_PACKAGE_VERSION}")
 
-    install(TARGETS aptdec DESTINATION "bin/")
-    file(GLOB_RECURSE DLLS *.dll)
-    install(FILES ${DLLS} DESTINATION "bin/")
+    if (TARGET aptdec)
+        install(TARGETS aptdec DESTINATION "bin/")
+        file(GLOB_RECURSE DLLS *.dll)
+        install(FILES ${DLLS} DESTINATION "bin/")
+    endif()
+    install(TARGETS libaptdec DESTINATION "bin/")
+    install(FILES ${LIB_C_HEADER_FILES} DESTINATION include/apt )
     install(DIRECTORY "${PROJECT_SOURCE_DIR}/palettes/" DESTINATION "palettes/")
 endif()
 

README.md

@@ -129,11 +129,18 @@ cmake ..
 make
 ```
 
-Since CMake is now being used for building, windows support has come. You can build for windows with the `build_windows.sh` script, you will need the following:
+You can cross build for Windows from Linux with the `build_windows.sh` script, you will need the following:
 ```
 sudo apt install wget cmake make mingw-w64 git unzip
 ```
 
+To build natively on Windows using MSVC, you will also need: git, ninja and cmake. Then run:
+```
+.\build_windows.bat
+```
+
+If you just wish to build libaptdec on Windows, libpng and libsndfile aren't needed.
+
 ## Further Reading
 
 [User's Guide for Building and Operating

build_windows.bat

@@ -0,0 +1,36 @@
+# Build using Visual Studio 2019 on Windows
+# Additional tools needed: git, cmake and ninja
+
+# Build zlib
+git clone https://github.com/madler/zlib
+cd zlib
+mkdir build
+cd build
+cmake -G Ninja -DCMAKE_C_COMPILER="cl.exe" -DMSVC_TOOLSET_VERSION=190 -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../../winpath ..
+ninja install
+cd ../../
+
+# Build libpng
+git clone https://github.com/glennrp/libpng
+cd libpng
+mkdir build
+cd build
+cmake -G Ninja -DCMAKE_C_COMPILER="cl.exe" -DMSVC_TOOLSET_VERSION=190 -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../../winpath ..
+ninja install
+cd ../..
+
+# Build libsndfile - Could build Vorbis, FLAC and Opus first for extra support
+git clone https://github.com/libsndfile/libsndfile.git
+cd libsndfile
+mkdir build
+cd build
+cmake -G Ninja -DCMAKE_C_COMPILER="cl.exe" -DMSVC_TOOLSET_VERSION=190 -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../../winpath ..
+ninja install
+cd ../..
+
+# Build aptdec
+mkdir winbuild
+cd winbuild
+cmake -G Ninja -DCMAKE_C_COMPILER="cl.exe" -DMSVC_TOOLSET_VERSION=190 -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../winpath ..
+ninja install
+cd ../..

build_windows.sh

@@ -1,3 +1,6 @@
+#!/bin/bash
+# Cross compile for Windows from Linux
+
 TEMP_PATH="$(pwd)/winpath"
 set -e
 

src/apt.h

@@ -0,0 +1,67 @@
+/*
+ *  This file is part of Aptdec.
+ *  Copyright (c) 2004-2009 Thierry Leconte (F4DWV), Xerbo (xerbo@protonmail.com) 2019-2020
+ *  Copyright (c) 2021 Jon Beniston (M7RCE)
+ *
+ *  Aptdec is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef APT_H
+#define APT_H
+
+#if defined (__GNUC__) && (__GNUC__ >= 4)
+#define APT_API __attribute__((visibility("default")))
+#elif defined (_MSC_VER)
+#define APT_API __declspec(dllexport)
+#else
+#define APT_API
+#endif
+
+// Maximum height of an APT image in number of scanlines
+#define APT_MAX_HEIGHT 3000
+
+// apt_getpixelrow callback function to get audio samples
+typedef int (*apt_getsample_t)(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
+	int chA, chB; // ID of each channel
+	char name[256]; // Stripped filename
+	char *palette; // Filename of palette
+} apt_image_t;
+
+typedef struct {
+	float r, g, b;
+} apt_rgb_t;
+
+int APT_API apt_init(double sample_rate);
+int APT_API apt_getpixelrow(float *pixelv, int nrow, int *zenith, int reset, apt_getsample_t getsample);
+
+void APT_API apt_histogramEqualise(float **prow, int nrow, int offset, int width);
+void APT_API apt_linearEnhance(float **prow, int nrow, int offset, int width);
+int APT_API apt_calibrate(float **prow, int nrow, int offset, int width) ;
+void APT_API apt_denoise(float **prow, int nrow, int offset, int width);
+void APT_API apt_flipImage(apt_image_t *img, int width, int offset);
+int APT_API apt_cropNoise(apt_image_t *img);
+
+apt_rgb_t APT_API apt_applyPalette(char *palette, int val);
+apt_rgb_t APT_API apt_RGBcomposite(apt_rgb_t top, float top_a, apt_rgb_t bottom, float bottom_a);
+
+char APT_API apt_TempPalette[256*3];
+char APT_API apt_PrecipPalette[58*3];
+
+#endif

src/color.c

@@ -17,18 +17,19 @@
  *
  */
 
+#include "apt.h"
 #include "color.h"
 
-rgb_t applyPalette(char *palette, int val){
-	return (rgb_t){
+apt_rgb_t apt_applyPalette(char *palette, int val){
+	return (apt_rgb_t){
 		palette[(int)CLIP(val, 0, 255)*3 + 0],
 		palette[(int)CLIP(val, 0, 255)*3 + 1],
 		palette[(int)CLIP(val, 0, 255)*3 + 2]
 	};
 }
 
-rgb_t RGBcomposite(rgb_t top, float top_a, rgb_t bottom, float bottom_a){
-	return (rgb_t){
+apt_rgb_t apt_RGBcomposite(apt_rgb_t top, float top_a, apt_rgb_t bottom, float bottom_a){
+	return (apt_rgb_t){
 		MCOMPOSITE(top.r, top_a, bottom.r, bottom_a),
 		MCOMPOSITE(top.g, top_a, bottom.g, bottom_a),
 		MCOMPOSITE(top.b, top_a, bottom.b, bottom_a)

src/color.h

@@ -1,9 +1,3 @@
 #include "common.h"
 
 #define MCOMPOSITE(m1, a1, m2, a2) (m1*a1 + m2*a2*(1-a1))
-
-rgb_t applyPalette(char *palette, int val);
-rgb_t RGBcomposite(rgb_t top, float top_a, rgb_t bottom, float bottom_a);
-
-extern char TempPalette[256*3];
-extern char PrecipPalette[58*3];

src/common.h

@@ -19,7 +19,6 @@
 
 // Constants
 #define VERSION "Aptdec; (c) 2004-2009 Thierry Leconte F4DWV, Xerbo (xerbo@protonmail.com) 2019-2020"
-#define MAX_HEIGHT 3000
 
 // Useful macros
 #define CLIP(v, lo, hi) (v > hi ? hi : (v > lo ? v : lo))
@@ -28,17 +27,6 @@
 // Typedefs
 #ifndef STRUCTS_DEFINED
 #define STRUCTS_DEFINED
-typedef struct {
-	float r, g, b;
-} rgb_t;
-typedef struct {
-	float *prow[MAX_HEIGHT]; // Row buffers
-	int nrow; // Number of rows
-	int zenith; // Row in image where satellite reaches peak elevation
-	int chA, chB; // ID of each channel
-	char name[256]; // Stripped filename
-	char *palette; // Filename of palette
-} image_t;
 typedef struct {
 	char *type; // Output image type
 	char *effects; // Effects on the image
@@ -70,4 +58,5 @@ enum effects {
 	Linear_Equalise='l',
 	Crop_Noise='c'
 };
+
 #endif

src/dsp.c

@@ -22,6 +22,7 @@
 #include <string.h>
 #include <math.h>
 
+#include "apt.h"
 #include "filter.h"
 
 // In case your C compiler is so old that Pi hadn't been invented yet
@@ -40,8 +41,6 @@
 #define RSMULT 15
 #define Fi (Fp * RSMULT)
 
-extern int getsample(float *inbuff, int count);
-
 static double Fe;
 
 static double offset = 0.0;
@@ -51,7 +50,7 @@ static double FreqOsc;
 static double K1, K2;
 
 // Check the sample rate and calculate some constants
-int init_dsp(double F) {
+int apt_init(double F) {
 	if(F > Fi) return 1;
 	if(F < Fp) return -1;
 	Fe = F;
@@ -132,7 +131,7 @@ static double pll(double I, double Q) {
 }
 
 // Convert samples into pixels
-static int getamp(double *ampbuff, int count) {
+static int getamp(double *ampbuff, int count, apt_getsample_t getsample) {
 	static float inbuff[BLKIN];
 	static int idxin = 0;
 	static int nin = 0;
@@ -169,7 +168,7 @@ static int getamp(double *ampbuff, int count) {
 }
 
 // Sub-pixel offsetting + FIR compensation
-int getpixelv(float *pvbuff, int count) {
+int getpixelv(float *pvbuff, int count, apt_getsample_t getsample) {
 	// Amplitude buffer
 	static double ampbuff[BLKAMP];
 	static int nam = 0;
@@ -179,7 +178,7 @@ int getpixelv(float *pvbuff, int count) {
 
 	// Gaussian resampling factor
 	mult = (double) Fi / Fe * FreqLine;
-	int m = RSFilterLen / mult + 1;
+	int m = (int)(RSFilterLen / mult + 1);
 
 	for (int n = 0; n < count; n++) {
 		int shift;
@@ -188,14 +187,14 @@ int getpixelv(float *pvbuff, int count) {
 			int res;
 			memmove(ampbuff, &(ampbuff[idxam]), nam * sizeof(double));
 			idxam = 0;
-			res = getamp(&(ampbuff[nam]), BLKAMP - nam);
+			res = getamp(&(ampbuff[nam]), BLKAMP - nam, getsample);
 			nam += res;
 			if (nam < m)
 				return n;
 		}
 
 		// Gaussian FIR compensation filter
-		pvbuff[n] = rsfir(&(ampbuff[idxam]), rsfilter, RSFilterLen, offset, mult) * mult * 256.0;
+		pvbuff[n] = (float)(rsfir(&(ampbuff[idxam]), rsfilter, RSFilterLen, offset, mult) * mult * 256.0);
 
 		shift = ((int) floor((RSMULT - offset) / mult)) + 1;
 		offset = shift * mult + offset - RSMULT;
@@ -208,7 +207,7 @@ int getpixelv(float *pvbuff, int count) {
 }
 
 // Get an entire row of pixels, aligned with sync markers
-int getpixelrow(float *pixelv, int nrow, int *zenith, int reset) {
+int apt_getpixelrow(float *pixelv, int nrow, int *zenith, int reset, apt_getsample_t getsample) {
 	static float pixels[PixelLine + SyncFilterLen];
 	static int npv;
 	static int synced = 0;
@@ -226,7 +225,7 @@ int getpixelrow(float *pixelv, int nrow, int *zenith, int reset) {
 
 	// Get the sync line
 	if (npv < SyncFilterLen + 2) {
-		res = getpixelv(&(pixelv[npv]), SyncFilterLen + 2 - npv);
+		res = getpixelv(&(pixelv[npv]), SyncFilterLen + 2 - npv, getsample);
 		npv += res;
 		if (npv < SyncFilterLen + 2)
 			return 0;
@@ -257,7 +256,7 @@ int getpixelrow(float *pixelv, int nrow, int *zenith, int reset) {
         static int lastmshift;
 
 		if (npv < PixelLine + SyncFilterLen) {
-			res = getpixelv(&(pixelv[npv]), PixelLine + SyncFilterLen - npv);
+			res = getpixelv(&(pixelv[npv]), PixelLine + SyncFilterLen - npv, getsample);
 			npv += res;
 			if (npv < PixelLine + SyncFilterLen)
 				return 0;
@@ -295,7 +294,7 @@ int getpixelrow(float *pixelv, int nrow, int *zenith, int reset) {
 
 	// Get the rest of this row
 	if (npv < PixelLine) {
-		res = getpixelv(&(pixelv[npv]), PixelLine - npv);
+		res = getpixelv(&(pixelv[npv]), PixelLine - npv, getsample);
 		npv += res;
 		if (npv < PixelLine)
 			return 0;

src/filter.c

@@ -27,7 +27,7 @@ float fir(float *buff, const float *coeff, const int len) {
 	for (int i = 0; i < len; i++) {
 		r += buff[i] * coeff[i];
 	}
-	return r;
+	return (float)r;
 }
 
 /* IQ finite impulse response
@@ -61,5 +61,5 @@ float rsfir(double *buff, const float *coeff, const int len, const double offset
 		alpha = n - k;
 		out += buff[i] * (coeff[k] * (1.0 - alpha) + coeff[k + 1] * alpha);
 	}
-	return out;
+	return (float)out;
 }

src/image.c

@@ -19,10 +19,10 @@
 
 #include <stdio.h>
 #include <string.h>
-#include <sndfile.h>
 #include <math.h>
 #include <stdlib.h>
 
+#include "apt.h"
 #include "offsets.h"
 #include "libs/reg.h"
 #include "image.h"
@@ -55,7 +55,7 @@ static double rgcal(float x, rgparam_t *rgpr) {
 static double tele[16];
 static double Cs;
 
-void histogramEqualise(float **prow, int nrow, int offset, int width){
+void apt_histogramEqualise(float **prow, int nrow, int offset, int width){
 	// Plot histogram
 	int histogram[256] = { 0 };
 	for(int y = 0; y < nrow; y++)
@@ -73,13 +73,13 @@ void histogramEqualise(float **prow, int nrow, int offset, int width){
 	int area = nrow * width;
 	for(int y = 0; y < nrow; y++){
 		for(int x = 0; x < width; x++){
-			int k = prow[y][x+offset];
-			prow[y][x+offset] = (256.0/area) * cf[k];
+			int k = (int)prow[y][x+offset];
+			prow[y][x+offset] = (256.0f/area) * cf[k];
 		}
 	}
 }
 
-void linearEnhance(float **prow, int nrow, int offset, int width){
+void apt_linearEnhance(float **prow, int nrow, int offset, int width){
 	// Plot histogram
 	int histogram[256] = { 0 };
 	for(int y = 0; y < nrow; y++)
@@ -98,8 +98,8 @@ void linearEnhance(float **prow, int nrow, int offset, int width){
 	// Stretch the brightness into the new range
 	for(int y = 0; y < nrow; y++){
 		for(int x = 0; x < width; x++){
-			prow[y][x+offset] = (prow[y][x+offset]-min) / (max-min) * 255.0;
-			prow[y][x+offset] = CLIP(prow[y][x+offset], 0.0, 255.0);
+			prow[y][x+offset] = (prow[y][x+offset]-min) / (max-min) * 255.0f;
+			prow[y][x+offset] = CLIP(prow[y][x+offset], 0.0f, 255.0f);
 		}
 	}
 }
@@ -110,7 +110,7 @@ void calibrateImage(float **prow, int nrow, int offset, int width, rgparam_t reg
 
 	for (int y = 0; y < nrow; y++) {
 		for (int x = 0; x < width+SYNC_WIDTH+SPC_WIDTH+TELE_WIDTH; x++) {
-			float pv = rgcal(prow[y][x + offset], &regr);
+			float pv = (float)rgcal(prow[y][x + offset], &regr);
 			prow[y][x + offset] = CLIP(pv, 0, 255);
 		}
 	}
@@ -126,10 +126,10 @@ double teleNoise(double wedges[16]){
 }
 
 // Get telemetry data for thermal calibration
-int calibrate(float **prow, int nrow, int offset, int width) {
-	double teleline[MAX_HEIGHT] = { 0.0 };
+int apt_calibrate(float **prow, int nrow, int offset, int width) {
+	double teleline[APT_MAX_HEIGHT] = { 0.0 };
 	double wedge[16];
-	rgparam_t regr[MAX_HEIGHT/FRAME_LEN + 1];
+	rgparam_t regr[APT_MAX_HEIGHT/FRAME_LEN + 1];
 	int telestart, mtelestart = 0;
 	int channel = -1;
 
@@ -156,8 +156,8 @@ int calibrate(float **prow, int nrow, int offset, int width) {
 		float df;
 
 		// (sum 4px below) - (sum 4px above)
-		df = (teleline[n - 4] + teleline[n - 3] + teleline[n - 2] + teleline[n - 1]) -
-			 (teleline[n + 0] + teleline[n + 1] + teleline[n + 2] + teleline[n + 3]);
+		df = (float)((teleline[n - 4] + teleline[n - 3] + teleline[n - 2] + teleline[n - 1]) -
+			     (teleline[n + 0] + teleline[n + 1] + teleline[n + 2] + teleline[n + 3]));
 
 		// Find the maximum difference
 		if (df > max) {
@@ -197,7 +197,7 @@ int calibrate(float **prow, int nrow, int offset, int width) {
 			// Compute & apply regression on the wedges
 			rgcomp(wedge, &regr[k]);
 			for (int j = 0; j < 16; j++)
-				tele[j] = rgcal(wedge[j], &regr[k]);
+				tele[j] = (float)rgcal((float)wedge[j], &regr[k]);
 
 			/* Compare the channel ID wedge to the reference
 			 * wedges, the wedge with the closest match will
@@ -205,7 +205,7 @@ int calibrate(float **prow, int nrow, int offset, int width) {
 			 */
 			float min = -1;
 			for (int j = 0; j < 6; j++) {
-				float df = tele[15] - tele[j];
+				float df = (float)(tele[15] - tele[j]);
 				df *= df;
 
 				if (df < min || min == -1) {
@@ -228,7 +228,7 @@ int calibrate(float **prow, int nrow, int offset, int width) {
 					i++;
 				}
 			}
-			Cs = rgcal(Cs / i, &regr[k]);
+			Cs = rgcal((float)(Cs / i), &regr[k]);
 		}
 	}
 
@@ -247,7 +247,7 @@ extern float quick_select(float arr[], int n);
 
 // Biased median denoise, pretyt ugly
 #define TRIG_LEVEL 40
-void denoise(float **prow, int nrow, int offset, int width){
+void apt_denoise(float **prow, int nrow, int offset, int width){
 	for(int y = 2; y < nrow-2; y++){
 		for(int x = offset+1; x < offset+width-1; x++){
 			if(prow[y][x+1] - prow[y][x] > TRIG_LEVEL ||
@@ -267,7 +267,7 @@ void denoise(float **prow, int nrow, int offset, int width){
 #undef TRIG_LEVEL
 
 // Flips a channel, for northbound passes
-void flipImage(image_t *img, int width, int offset){
+void apt_flipImage(apt_image_t *img, int width, int offset){
 	for(int y = 1; y < img->nrow; y++){
 		for(int x = 1; x < ceil(width / 2.0); x++){
 			// Flip top-left & bottom-right
@@ -279,11 +279,11 @@ void flipImage(image_t *img, int width, int offset){
 }
 
 // Calculate crop to reomve noise from the start and end of an image
-int cropNoise(image_t *img){
+int apt_cropNoise(apt_image_t *img){
 	#define NOISE_THRESH 180.0
 
 	// Average value of minute marker
-	float spc_rows[MAX_HEIGHT] = { 0.0 };
+	float spc_rows[APT_MAX_HEIGHT] = { 0.0 };
 	int startCrop = 0; int endCrop = img->nrow;
 	for(int y = 0; y < img->nrow; y++) {
 		for(int x = 0; x < SPC_WIDTH; x++) {
@@ -396,7 +396,7 @@ static double tempcal(float Ce, int satnum, tempparam_t * rgpr) {
 }
 
 // Temperature calibration wrapper
-void temperature(options_t *opts, image_t *img, int offset, int width){
+void temperature(options_t *opts, apt_image_t *img, int offset, int width){
 	tempparam_t temp;
 
 	printf("Temperature... ");
@@ -406,7 +406,7 @@ void temperature(options_t *opts, image_t *img, int offset, int width){
 
 	for (int y = 0; y < img->nrow; y++) {
 		for (int x = 0; x < width; x++) {
-			img->prow[y][x + offset] = tempcal(img->prow[y][x + offset], opts->satnum - 15, &temp);
+			img->prow[y][x + offset] = (float)tempcal(img->prow[y][x + offset], opts->satnum - 15, &temp);
 		}
 	}
 	printf("Done\n");

src/image.h

@@ -1,9 +1,4 @@
+#include "apt.h"
 #include "common.h"
 
-void histogramEqualise(float **prow, int nrow, int offset, int width);
-void linearEnhance(float **prow, int nrow, int offset, int width);
-int calibrate(float **prow, int nrow, int offset, int width) ;
-void denoise(float **prow, int nrow, int offset, int width);
-void flipImage(image_t *img, int width, int offset);
-int cropNoise(image_t *img);
-void temperature(options_t *opts, image_t *img, int offset, int width);
+void APT_API temperature(options_t *opts, apt_image_t *img, int offset, int width);

src/main.c

@@ -20,7 +20,11 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#ifndef _MSC_VER
 #include <libgen.h>
+#else
+#include <windows.h>
+#endif
 #include <math.h>
 #include <sndfile.h>
 #include <errno.h>
@@ -28,10 +32,8 @@
 #include "libs/argparse.h"
 
 #include "offsets.h"
-
-// DSP
-extern int init_dsp(double F);
-extern int getpixelrow(float *pixelv, int nrow, int *zenith, int reset);
+#include "common.h"
+#include "apt.h"
 
 #include "pngio.h"
 #include "image.h"
@@ -47,6 +49,23 @@ static int initsnd(char *filename);
 int getsample(float *sample, int nb);
 static int processAudio(char *filename, options_t *opts);
 
+#ifdef _MSC_VER
+// Functions not supported by MSVC
+static char *dirname(char *path)
+{
+	static char dir[MAX_PATH];
+	_splitpath(path, NULL, dir, NULL, NULL);
+        return dir;
+}
+
+static char *basename(char *path)
+{
+	static char base[MAX_PATH];
+	_splitpath(path, NULL, NULL, base, NULL);
+        return base;
+}
+#endif
+
 int main(int argc, const char **argv) {
 	options_t opts = { "r", "", 19, "", ".", 0, "", "", 1.0, 0 };
 
@@ -98,7 +117,7 @@ int main(int argc, const char **argv) {
 
 static int processAudio(char *filename, options_t *opts){
 	// Image info struct
-	image_t img;
+	apt_image_t img;
 
 	// Mapping between wedge value and channel ID
 	static struct {
@@ -125,7 +144,7 @@ static int processAudio(char *filename, options_t *opts){
 		strncpy(img.name, ctime(&t), 24);
 
 		// Init a row writer
-		initWriter(opts, &img, IMG_WIDTH, MAX_HEIGHT, "Unprocessed realtime image", "r");
+		initWriter(opts, &img, IMG_WIDTH, APT_MAX_HEIGHT, "Unprocessed realtime image", "r");
 	}		
 
 	if(strcmp(extension, "png") == 0){
@@ -141,12 +160,12 @@ static int processAudio(char *filename, options_t *opts){
 
 		// Build image
 		// TODO: multithreading, would require some sort of input buffer
-		for (img.nrow = 0; img.nrow < MAX_HEIGHT; img.nrow++) {
+		for (img.nrow = 0; img.nrow < APT_MAX_HEIGHT; img.nrow++) {
 			// Allocate memory for this row
 			img.prow[img.nrow] = (float *) malloc(sizeof(float) * 2150);
 
 			// Write into memory and break the loop when there are no more samples to read
-			if (getpixelrow(img.prow[img.nrow], img.nrow, &img.zenith, (img.nrow == 0)) == 0)
+			if (apt_getpixelrow(img.prow[img.nrow], img.nrow, &img.zenith, (img.nrow == 0), getsample) == 0)
 				break;
 
 			if(opts->realtime) pushRow(img.prow[img.nrow], IMG_WIDTH);
@@ -171,32 +190,32 @@ static int processAudio(char *filename, options_t *opts){
 	}
 
 	// Calibrate
-	img.chA = calibrate(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
-	img.chB = calibrate(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
+	img.chA = apt_calibrate(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
+	img.chB = apt_calibrate(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
 	printf("Channel A: %s (%s)\n", ch.id[img.chA], ch.name[img.chA]);
 	printf("Channel B: %s (%s)\n", ch.id[img.chB], ch.name[img.chB]);
 
 	// Crop noise from start and end of image
 	if(CONTAINS(opts->effects, Crop_Noise)){
-		img.zenith -= cropNoise(&img);
+		img.zenith -= apt_cropNoise(&img);
 	}
 
 	// Denoise
 	if(CONTAINS(opts->effects, Denoise)){
-		denoise(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
-		denoise(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
+		apt_denoise(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
+		apt_denoise(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
 	}
 
 	// Flip, for northbound passes
 	if(CONTAINS(opts->effects, Flip_Image)){
-		flipImage(&img, CH_WIDTH, CHA_OFFSET);
-		flipImage(&img, CH_WIDTH, CHB_OFFSET);
+		apt_flipImage(&img, CH_WIDTH, CHA_OFFSET);
+		apt_flipImage(&img, CH_WIDTH, CHB_OFFSET);
 	}
 
 	// Temperature
 	if (CONTAINS(opts->type, Temperature) && img.chB >= 4) {
 		// Create another buffer as to not modify the orignal
-		image_t tmpimg = img;
+		apt_image_t tmpimg = img;
 		for(int i = 0; i < img.nrow; i++){
 			tmpimg.prow[i] = (float *) malloc(sizeof(float) * 2150);
 			memcpy(tmpimg.prow[i], img.prow[i], sizeof(float) * 2150);
@@ -204,7 +223,7 @@ static int processAudio(char *filename, options_t *opts){
 
 		// Perform temperature calibration
 		temperature(opts, &tmpimg, CHB_OFFSET, CH_WIDTH);
-		ImageOut(opts, &tmpimg, CHB_OFFSET, CH_WIDTH, "Temperature", Temperature, (char *)TempPalette);
+		ImageOut(opts, &tmpimg, CHB_OFFSET, CH_WIDTH, "Temperature", Temperature, (char *)apt_TempPalette);
 	}
 
 	// MCIR
@@ -213,14 +232,14 @@ static int processAudio(char *filename, options_t *opts){
 
 	// Linear equalise
 	if(CONTAINS(opts->effects, Linear_Equalise)){
-		linearEnhance(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
-		linearEnhance(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
+		apt_linearEnhance(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
+		apt_linearEnhance(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
 	}
 
 	// Histogram equalise
 	if(CONTAINS(opts->effects, Histogram_Equalise)){
-		histogramEqualise(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
-		histogramEqualise(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
+		apt_histogramEqualise(img.prow, img.nrow, CHA_OFFSET, CH_WIDTH);
+		apt_histogramEqualise(img.prow, img.nrow, CHB_OFFSET, CH_WIDTH);
 	}
 
 	// Raw image
@@ -263,7 +282,7 @@ static int initsnd(char *filename) {
 		return 0;
 	}
 
-	res = init_dsp(infwav.samplerate);
+	res = apt_init(infwav.samplerate);
 	printf("Input file: %s\n", filename);
 	if(res < 0) {
 		fprintf(stderr, "Input sample rate too low: %d\n", infwav.samplerate);
@@ -282,14 +301,15 @@ static int initsnd(char *filename) {
 // Read samples from the audio file
 int getsample(float *sample, int nb) {
 	if(channels == 1){
-		return sf_read_float(audioFile, sample, nb);
+		return (int)sf_read_float(audioFile, sample, nb);
 	}else{
 		/* Multi channel audio is encoded such as:
 		 *  Ch1,Ch2,Ch1,Ch2,Ch1,Ch2
 		 */
-		float buf[nb * channels]; // Something like BLKIN*2 could also be used
-		int samples = sf_read_float(audioFile, buf, nb * channels);
+		float *buf = malloc(sizeof(float) * nb * channels); // Something like BLKIN*2 could also be used
+		int samples = (int)sf_read_float(audioFile, buf, nb * channels);
 		for(int i = 0; i < nb; i++) sample[i] = buf[i * channels];
+		free(buf);
 		return samples / channels;
 	}
 }

src/pngio.c

@@ -26,7 +26,7 @@
 
 #include "pngio.h"
 
-int mapOverlay(char *filename, rgb_t **crow, int nrow, int zenith, int MCIR) {
+int mapOverlay(char *filename, apt_rgb_t **crow, int nrow, int zenith, int MCIR) {
 	FILE *fp = fopen(filename, "rb");
 	if(!fp) {
 		fprintf(stderr, "Cannot open %s\n", filename);
@@ -88,7 +88,7 @@ int mapOverlay(char *filename, rgb_t **crow, int nrow, int zenith, int MCIR) {
 		for(int x = 49; x < width - 82; x++){
 			// Maps are 16 bit / channel
 			png_bytep px = &mapRows[CLIP(y + mapOffset, 0, height-1)][x * 6];
-			rgb_t map = {
+			apt_rgb_t map = {
 				(px[0] << 8) | px[1],
 				(px[2] << 8) | px[3],
 				(px[4] << 8) | px[5]
@@ -105,10 +105,10 @@ int mapOverlay(char *filename, rgb_t **crow, int nrow, int zenith, int MCIR) {
 					float darken = ((255-crow[y][chb].r)-100)/50;
 					float green = CLIP(map.g/300, 0, 1);
 					float blue = 0.15 - CLIP(map.b/960.0, 0, 1);
-					crow[y][cha] = (rgb_t){blue*1000*darken, green*98*darken, blue*500.0*darken};
+					crow[y][cha] = (apt_rgb_t){blue*1000*darken, green*98*darken, blue*500.0*darken};
 				}else{
 					// Sea
-					crow[y][cha] = (rgb_t){9, 17, 74};
+					crow[y][cha] = (apt_rgb_t){9, 17, 74};
 				}
 			}
 
@@ -125,15 +125,15 @@ int mapOverlay(char *filename, rgb_t **crow, int nrow, int zenith, int MCIR) {
 			map.b = CLIP(map.b, 0, 255.0);
 
 			// Map overlay on channel A
-			crow[y][cha] = RGBcomposite(map, alpha, crow[y][cha], 1);
+			crow[y][cha] = apt_RGBcomposite(map, alpha, crow[y][cha], 1);
 			// Map overlay on channel B
 			if(!MCIR)
-				crow[y][chb] = RGBcomposite(map, alpha, crow[y][chb], 1);
+				crow[y][chb] = apt_RGBcomposite(map, alpha, crow[y][chb], 1);
 
 			// Cloud overlay on channel A
 			if(MCIR){
 				float cloud = CLIP((crow[y][chb].r - 113) / 90.0, 0, 1);
-				crow[y][cha] = RGBcomposite((rgb_t){255, 250, 245}, cloud, crow[y][cha], 1);
+				crow[y][cha] = apt_RGBcomposite((apt_rgb_t){255, 250, 245}, cloud, crow[y][cha], 1);
 			}
 		}
 	}
@@ -206,7 +206,7 @@ int readRawImage(char *filename, float **prow, int *nrow) {
 	return 1;
 }
 
-int readPalette(char *filename, rgb_t **pixels) {
+int readPalette(char *filename, apt_rgb_t **pixels) {
 	FILE *fp = fopen(filename, "rb");
 	if(!fp) {
 		char buffer[1024];
@@ -266,10 +266,10 @@ int readPalette(char *filename, rgb_t **pixels) {
 
 	// Put into crow
 	for(int y = 0; y < height; y++) {
-		pixels[y] = (rgb_t *) malloc(sizeof(rgb_t) * width);
+		pixels[y] = (apt_rgb_t *) malloc(sizeof(apt_rgb_t) * width);
 
 		for(int x = 0; x < width; x++)
-			pixels[y][x] = (rgb_t){
+			pixels[y][x] = (apt_rgb_t){
 				PNGrows[y][x*3],
 				PNGrows[y][x*3 + 1], 
 				PNGrows[y][x*3 + 2]
@@ -279,21 +279,21 @@ int readPalette(char *filename, rgb_t **pixels) {
 	return 1;
 }
 
-void prow2crow(float **prow, int nrow, char *palette, rgb_t **crow){
+void prow2crow(float **prow, int nrow, char *palette, apt_rgb_t **crow){
 	for(int y = 0; y < nrow; y++){
-		crow[y] = (rgb_t *) malloc(sizeof(rgb_t) * IMG_WIDTH);
+		crow[y] = (apt_rgb_t *) malloc(sizeof(apt_rgb_t) * IMG_WIDTH);
 
 		for(int x = 0; x < IMG_WIDTH; x++){
 			if(palette == NULL)
 				crow[y][x].r = crow[y][x].g = crow[y][x].b = prow[y][x];
 			else
-				crow[y][x] = applyPalette(palette, prow[y][x]);
+				crow[y][x] = apt_applyPalette(palette, prow[y][x]);
 		}
 	}
 }
 
-int applyUserPalette(float **prow, int nrow, char *filename, rgb_t **crow){
-	rgb_t *pal_row[256];
+int applyUserPalette(float **prow, int nrow, char *filename, apt_rgb_t **crow){
+	apt_rgb_t *pal_row[256];
 	if(!readPalette(filename, pal_row)){
 		fprintf(stderr, "Could not read palette\n");
 		return 0;
@@ -310,7 +310,7 @@ int applyUserPalette(float **prow, int nrow, char *filename, rgb_t **crow){
 	return 1;
 }
 
-int ImageOut(options_t *opts, image_t *img, int offset, int width, char *desc, char chid, char *palette){
+int ImageOut(options_t *opts, apt_image_t *img, int offset, int width, char *desc, char chid, char *palette){
 	char outName[512];
 	if(opts->filename == NULL || opts->filename[0] == '\0'){
 		sprintf(outName, "%s/%s-%c.png", opts->path, img->name, chid);
@@ -409,7 +409,7 @@ int ImageOut(options_t *opts, image_t *img, int offset, int width, char *desc, c
 	png_write_info(png_ptr, info_ptr);
 
 	// Move prow into crow, crow ~ color rows, if required
-	rgb_t *crow[MAX_HEIGHT];
+	apt_rgb_t *crow[APT_MAX_HEIGHT];
 	if(!greyscale){
 		prow2crow(img->prow, img->nrow, palette, crow);
 	}
@@ -424,7 +424,7 @@ int ImageOut(options_t *opts, image_t *img, int offset, int width, char *desc, c
 		for(int y = 0; y < img->nrow; y++){
 			for(int x = 0; x < CH_WIDTH; x++){
 				if(img->prow[y][x + CHB_OFFSET] >= 198)
-					crow[y][x + CHB_OFFSET] = crow[y][x + CHA_OFFSET] = applyPalette(PrecipPalette, img->prow[y][x + CHB_OFFSET]-198);
+					crow[y][x + CHB_OFFSET] = crow[y][x + CHA_OFFSET] = apt_applyPalette(apt_PrecipPalette, img->prow[y][x + CHB_OFFSET]-198);
 			}
 		}
 	}
@@ -448,8 +448,8 @@ int ImageOut(options_t *opts, image_t *img, int offset, int width, char *desc, c
 
 	// Build image
 	for (int y = 0; y < img->nrow; y++) {
-		png_color pix[width]; // Color
-		png_byte mpix[width]; // Mono
+		png_color pix[IMG_WIDTH]; // Color
+		png_byte mpix[IMG_WIDTH]; // Mono
 
 		int skip = 0;
 		for (int x = 0; x < width; x++) {
@@ -488,7 +488,7 @@ png_structp rt_png_ptr;
 png_infop rt_info_ptr;
 FILE *rt_pngfile;
 
-int initWriter(options_t *opts, image_t *img, int width, int height, char *desc, char *chid){
+int initWriter(options_t *opts, apt_image_t *img, int width, int height, char *desc, char *chid){
 	char outName[384];
 	sprintf(outName, "%s/%s-%s.png", opts->path, img->name, chid);
 
@@ -538,7 +538,7 @@ int initWriter(options_t *opts, image_t *img, int width, int height, char *desc,
 }
 
 void pushRow(float *row, int width){
-	png_byte pix[width];
+	png_byte pix[IMG_WIDTH];
 	for(int i = 0; i < width; i++)
 		pix[i] = row[i];
 

src/pngio.h

@@ -1,13 +1,13 @@
+#include "apt.h"
 #include "common.h"
 #include "offsets.h"
-#include "color.h"
 
-int mapOverlay(char *filename, rgb_t **crow, int nrow, int zenith, int MCIR);
+int mapOverlay(char *filename, apt_rgb_t **crow, int nrow, int zenith, int MCIR);
 int readRawImage(char *filename, float **prow, int *nrow);
-int readPalette(char *filename, rgb_t **pixels);
-void prow2crow(float **prow, int nrow, char *palette, rgb_t **crow);
-int applyUserPalette(float **prow, int nrow, char *filename, rgb_t **crow);
-int ImageOut(options_t *opts, image_t *img, int offset, int width, char *desc, char chid, char *palette);
-int initWriter(options_t *opts, image_t *img, int width, int height, char *desc, char *chid);
+int readPalette(char *filename, apt_rgb_t **pixels);
+void prow2crow(float **prow, int nrow, char *palette, apt_rgb_t **crow);
+int applyUserPalette(float **prow, int nrow, char *filename, apt_rgb_t **crow);
+int ImageOut(options_t *opts, apt_image_t *img, int offset, int width, char *desc, char chid, char *palette);
+int initWriter(options_t *opts, apt_image_t *img, int width, int height, char *desc, char *chid);
 void pushRow(float *row, int width);
 void closeWriter();

src/satcal.h

@@ -32,94 +32,94 @@ const struct {
 } satcal[] = {
 { // NOAA 15
 	{ // PRT coefficient d0, d1, d2
-		{276.60157, 0.051045, 1.36328E-06},
-		{276.62531, 0.050909, 1.47266E-06},
-		{276.67413, 0.050907, 1.47656E-06},
-		{276.59258, 0.050966, 1.47656E-06}
+		{276.60157f, 0.051045f, 1.36328E-06f},
+		{276.62531f, 0.050909f, 1.47266E-06f},
+		{276.67413f, 0.050907f, 1.47656E-06f},
+		{276.59258f, 0.050966f, 1.47656E-06f}
 	},
 	{ // Channel radiance coefficient vc, A, B
-		{925.4075, 0.337810, 0.998719}, // Channel 4
-		{839.8979, 0.304558, 0.999024}, // Channel 5
-		{2695.9743, 1.621256, 0.998015} // Channel 3B
+		{925.4075f, 0.337810f, 0.998719f}, // Channel 4
+		{839.8979f, 0.304558f, 0.999024f}, // Channel 5
+		{2695.9743f, 1.621256f, 0.998015f} // Channel 3B
 	},
 	{ // Nonlinear radiance correction Ns, b0, b1, b2
-		{-4.50, {4.76, -0.0932, 0.0004524}}, // Channel 4
-		{-3.61, {3.83, -0.0659, 0.0002811}}, // Channel 5
-		{0.0, {0.0, 0.0, 0.0}} // Channel 3B
+		{-4.50f, {4.76f, -0.0932f, 0.0004524f}}, // Channel 4
+		{-3.61f, {3.83f, -0.0659f, 0.0002811f}}, // Channel 5
+		{0.0f, {0.0f, 0.0f, 0.0f}} // Channel 3B
 	}
 },
 { // NOAA 16
 	{ // PRT coeff d0, d1, d2
-		{276.355, 5.562E-02, -1.590E-05},
-		{276.142, 5.605E-02, -1.707E-05},
-		{275.996, 5.486E-02, -1.223E-05},
-		{276.132, 5.494E-02, -1.344E-05}
+		{276.355f, 5.562E-02f, -1.590E-05f},
+		{276.142f, 5.605E-02f, -1.707E-05f},
+		{275.996f, 5.486E-02f, -1.223E-05f},
+		{276.132f, 5.494E-02f, -1.344E-05f}
 	},
 	{ // Channel radiance coefficient vc, A, B
-		{917.2289, 0.332380, 0.998522}, // Channel 4
-		{838.1255, 0.674623, 0.998363}, // Channel 5
-		{2700.1148, 1.592459, 0.998147} // Channel 3B
+		{917.2289f, 0.332380f, 0.998522f}, // Channel 4
+		{838.1255f, 0.674623f, 0.998363f}, // Channel 5
+		{2700.1148f, 1.592459f, 0.998147f} // Channel 3B
 	},
 	{ // Nonlinear radiance correction Ns, b0, b1, b2
-		{-2.467, {2.96, -0.05411, 0.00024532}}, // Channel 4
-		{-2.009, {2.25, -0.03665, 0.00014854}}, // Channel 5
-		{0.0, {0.0, 0.0, 0.0}}  // Channel 3B
+		{-2.467f, {2.96f, -0.05411f, 0.00024532f}}, // Channel 4
+		{-2.009f, {2.25f, -0.03665f, 0.00014854f}}, // Channel 5
+		{0.0f, {0.0f, 0.0f, 0.0f}}  // Channel 3B
 	}
 },
 { // NOAA 17
 	{ // PRT coefficient d0, d1, d2
-		{276.628, 0.05098, 1.371e-06},
-		{276.538, 0.05098, 1.371e-06},
-		{276.761, 0.05097, 1.369e-06},
-		{276.660, 0.05100, 1.348e-06}
+		{276.628f, 0.05098f, 1.371e-06f},
+		{276.538f, 0.05098f, 1.371e-06f},
+		{276.761f, 0.05097f, 1.369e-06f},
+		{276.660f, 0.05100f, 1.348e-06f}
 	},
 	{ // Channel radiance coefficient vc, A, B
-		{926.2947, 0.271683, 0.998794}, // Channel 4
-		{839.8246, 0.309180, 0.999012}, // Channel 5
-		{2669.3554, 1.702380, 0.997378} // Channel 3B
+		{926.2947f, 0.271683f, 0.998794f}, // Channel 4
+		{839.8246f, 0.309180f, 0.999012f}, // Channel 5
+		{2669.3554f, 1.702380f, 0.997378f} // Channel 3B
 	},
 	{ // Nonlinear radiance correction Ns, b0, b1, b2
-		{-8.55, {8.22, -0.15795, 0.00075579}}, // Channel 4
-		{-3.97, {4.31, -0.07318, 0.00030976}}, // Channel 5
-		{0.0, {0.0, 0.0, 0.0}} // Channel 3B
+		{-8.55f, {8.22f, -0.15795f, 0.00075579f}}, // Channel 4
+		{-3.97f, {4.31f, -0.07318f, 0.00030976f}}, // Channel 5
+		{0.0f, {0.0f, 0.0f, 0.0f}} // Channel 3B
 	}
 },
 { // NOAA 18
 	{ // PRT coefficient d0, d1, d2
-		{276.601, 0.05090, 1.657e-06},
-		{276.683, 0.05101, 1.482e-06},
-		{276.565, 0.05117, 1.313e-06},
-		{276.615, 0.05103, 1.484e-06}
+		{276.601f, 0.05090f, 1.657e-06f},
+		{276.683f, 0.05101f, 1.482e-06f},
+		{276.565f, 0.05117f, 1.313e-06f},
+		{276.615f, 0.05103f, 1.484e-06f}
 	},
 	{ // Channel radiance coefficient vc, A, B
-		{928.1460, 0.436645, 0.998607}, // Channel 4
-		{833.2532, 0.253179, 0.999057}, // Channel 5
-		{2659.7952, 1.698704, 0.996960} // Channel 3B
+		{928.1460f, 0.436645f, 0.998607f}, // Channel 4
+		{833.2532f, 0.253179f, 0.999057f}, // Channel 5
+		{2659.7952f, 1.698704f, 0.996960f} // Channel 3B
 	},
 	{ // Nonlinear radiance correction Ns, b0, b1, b2
-		{-5.53, {5.82, -0.11069, 0.00052337}}, // Channel 4
-		{-2.22, {2.67, -0.04360, 0.00017715}}, // Channel 5
-		{0.0, {0.0, 0.0, 0.0}} // Channel 3B
+		{-5.53f, {5.82f, -0.11069f, 0.00052337f}}, // Channel 4
+		{-2.22f, {2.67f, -0.04360f, 0.00017715f}}, // Channel 5
+		{0.0f, {0.0f, 0.0f, 0.0f}} // Channel 3B
 	}
 },
 { // NOAA 19
 	{ // PRT coefficient d0, d1, d2
-		{276.6067, 0.051111, 1.405783E-06},
-		{276.6119, 0.051090, 1.496037E-06},
-		{276.6311, 0.051033, 1.496990E-06},
-		{276.6268, 0.051058, 1.493110E-06}
+		{276.6067f, 0.051111f, 1.405783E-06f},
+		{276.6119f, 0.051090f, 1.496037E-06f},
+		{276.6311f, 0.051033f, 1.496990E-06f},
+		{276.6268f, 0.051058f, 1.493110E-06f}
 	},
 	{ // Channel radiance coefficient vc, A, B
-		{928.9, 0.53959, 0.998534}, // Channel 4
-		{831.9, 0.36064, 0.998913}, // Channel 5
-		{2670.0, 1.67396, 0.997364} // Channel 3B
+		{928.9f, 0.53959f, 0.998534f}, // Channel 4
+		{831.9f, 0.36064f, 0.998913f}, // Channel 5
+		{2670.0f, 1.67396f, 0.997364f} // Channel 3B
 	},
 	{ // Nonlinear radiance correction Ns, b0, b1, b2
-		{-5.49, {5.70 	-0.11187, 0.00054668}}, // Channel 4
-		{-3.39, {3.58 	-0.05991, 0.00024985}}, // Channel 5
-		{0.0, {0.0, 0.0, 0.0}} // Channel 3B
+		{-5.49f, {5.70f, -0.11187f, 0.00054668f}}, // Channel 4
+		{-3.39f, {3.58f, -0.05991f, 0.00024985f}}, // Channel 5
+		{0.0f, {0.0f, 0.0f, 0.0f}} // Channel 3B
 	}
 }};
 
-const float c1 = 1.1910427e-5;
-const float c2 = 1.4387752;
+const float c1 = 1.1910427e-5f;
+const float c2 = 1.4387752f;