Cross-compiling prototype

README.md

@@ -56,4 +56,18 @@ make install
 
 On Windows system, you will probably need to specify the dependency flags for CMake. Ex:
 
-`cmake.exe -D"ZLIB_INCLUDE_DIR=zlib/1.2.11/include" -D"ZLIB_LIBRARY=zlib/1.2.11/libzlib.dll.a" -D"PNG_PNG_INCLUDE_DIR=libpng/1.6.37/include" -D"PNG_LIBRARY=libpng/1.6.37/libpng.dll.a" . -G "MinGW Makefiles"`
+`cmake.exe -D"ZLIB_INCLUDE_DIR=zlib/1.2.11/include" -D"ZLIB_LIBRARY=zlib/1.2.11/lib/libzlib.dll.a" -D"PNG_PNG_INCLUDE_DIR=libpng/1.6.37/include" -D"PNG_LIBRARY=libpng/1.6.37/lib/libpng.dll.a" . -G "MinGW Makefiles"`
+
+We can also use cross-compilation (after installing `mingw64` and `cmake` packages on your distrib):
+
+```shell
+mkdir build && cd build
+cmake -DGNU_HOST=x86_64-w64-mingw32 \
+	-DCMAKE_TOOLCHAIN_FILE=../mingw_cross_toolchain.cmake \
+	-D"ZLIB_INCLUDE_DIR=zlib/1.2.11/include" \
+	-D"ZLIB_LIBRARY=zlib/1.2.11/lib/libzlib.dll.a" \
+	-D"PNG_PNG_INCLUDE_DIR=libpng/1.6.37/include" \
+	-D"PNG_LIBRARY=libpng/1.6.37/lib/libpng.dll.a" \
+	..
+cmake --build .
+```

mingw_cross_toolchain.cmake

@@ -0,0 +1,8 @@
+SET(CMAKE_SYSTEM_NAME Windows)
+IF("${GNU_HOST}" STREQUAL "")
+    SET(GNU_HOST i586-mingw32msvc)
+ENDIF()
+# Prefix detection only works with compiler id "GNU"
+SET(CMAKE_C_COMPILER ${GNU_HOST}-gcc)
+# CMake doesn't automatically look for prefixed 'windres', do it manually:
+SET(CMAKE_RC_COMPILER ${GNU_HOST}-windres)

src/RS_images.c

@@ -104,8 +104,11 @@ void convert8bitsTo32bitsRGBA(unsigned char *samples_tab, PIXEL_A *pixels_tab, i
 void useOddBytes(unsigned char *src, PIXEL_A *dst, int size) {
 	int i;
 
-	for(i=0; i<size; i++) {
+	for(i=0; i<(size-1); i++) {
-		//dst[i] = src[i*2+1];
+		//dst[i] = src[i*2+1];			//FIXME: Implement optimized byte shifting
+		//dst[i]._red = src[i*2+1];
+		//dst[i]._green = src[i*2+1];
+		//dst[i]._blue = src[i*2+1];
 	}
 }
 

src/config.h.in

@@ -1 +1 @@
-#define VERSION "@PROJECT_VERSION@"
+#define VERSION "@PROJECT_VERSION@"