BACKENDS: Add special Win32 path to set SDL window icon

We bypass SDL_WM_SetIcon and setup the window icon using the embedded icon, with the default path as a fallback.
This allows us to use an antialised icon with alpha transparency (which the default included icon doesn't have) on Windows XP and later

2 files changed, 25 insertions, 0 deletions

diff --git a/backends/platform/sdl/win32/win32.cpp b/backends/platform/sdl/win32/win32.cpp
index 814f1955fe..420ed2465b 100644
--- a/backends/platform/sdl/win32/win32.cpp
+++ b/backends/platform/sdl/win32/win32.cpp
@@ -34,6 +34,8 @@
 #undef ARRAYSIZE // winnt.h defines ARRAYSIZE, but we want our own one...
 #include <shellapi.h>
 
+#include <SDL_syswm.h> // For setting the icon
+
 #include "backends/platform/sdl/win32/win32.h"
 #include "backends/fs/windows/windows-fs-factory.h"
 #include "backends/taskbar/win32/win32-taskbar.h"
@@ -137,6 +139,28 @@ bool OSystem_Win32::displayLogFile() {
 	return false;
 }
 
+void OSystem_Win32::setupIcon() {
+	HMODULE handle = GetModuleHandle(NULL);
+	HICON   ico    = LoadIcon(handle, MAKEINTRESOURCE(1001 /* IDI_ICON */));
+	if (ico) {
+		SDL_SysWMinfo  wminfo;
+		SDL_VERSION(&wminfo.version);
+		if (SDL_GetWMInfo(&wminfo)) {
+			// Replace the handle to the icon associated with the window class by our custom icon
+			SetClassLongPtr(wminfo.window, GCLP_HICON, (ULONG_PTR)ico);
+
+			// Since there wasn't any default icon, we can't use the return value from SetClassLong
+			// to check for errors (it would be 0 in both cases: error or no previous value for the
+			// icon handle). Instead we check for the last-error code value.
+			if (GetLastError() == ERROR_SUCCESS)
+				return;
+		}
+	}
+
+	// If no icon has been set, fallback to default path
+	OSystem_SDL::setupIcon();
+}
+
 Common::String OSystem_Win32::getDefaultConfigFileName() {
 	char configFile[MAXPATHLEN];
 
diff --git a/backends/platform/sdl/win32/win32.h b/backends/platform/sdl/win32/win32.h
index ef7b6af3f1..cc2fc51d36 100644
--- a/backends/platform/sdl/win32/win32.h
+++ b/backends/platform/sdl/win32/win32.h
@@ -46,6 +46,7 @@ protected:
 	 */
 	Common::String _logFilePath;
 
+	virtual void setupIcon();
 	virtual Common::String getDefaultConfigFileName();
 	virtual Common::WriteStream *createLogFile();
 };