Finally set a window icon on X11

Since the creation of minetest, it had no window icon on X11.
Now we have one.

The misc/minetest-xorg-icon-128.png file is a rendering of the
misc/minetest.svg file with inkscape, created with something like:

inkscape -z -e misc/minetest-xorg-icon-128.png -w 128 -h 128 misc/minetest.svg

src/client/clientlauncher.cpp

@@ -114,6 +114,9 @@ bool ClientLauncher::run(GameParams &game_params, const Settings &cmd_args)
 
 	porting::setXorgClassHint(video_driver->getExposedVideoData(), PROJECT_NAME_C);
 
+	porting::setXorgWindowIcon(device,
+		porting::path_share + "/misc/minetest-xorg-icon-128.png");
+
 	/*
 		This changes the minimum allowed number of vertices in a VBO.
 		Default is 500.

src/porting.cpp

@@ -611,6 +611,93 @@ void setXorgClassHint(const video::SExposedVideoData &video_data,
 #endif
 }
 
+bool setXorgWindowIcon(IrrlichtDevice *device,
+	const std::string &icon_file)
+{
+#ifdef XORG_USED
+
+	video::IVideoDriver *v_driver = device->getVideoDriver();
+
+	video::IImageLoader *image_loader = NULL;
+	for (u32 i = v_driver->getImageLoaderCount() - 1; i >= 0; i--) {
+		if (v_driver->getImageLoader(i)->isALoadableFileExtension(icon_file.c_str())) {
+			image_loader = v_driver->getImageLoader(i);
+			break;
+		}
+	}
+
+	if (!image_loader) {
+		warningstream << "Could not find image loader for file '"
+			<< icon_file << "'" << std::endl;
+		return false;
+	}
+
+	io::IReadFile *icon_f = device->getFileSystem()->createAndOpenFile(icon_file.c_str());
+
+	if (!icon_f) {
+		warningstream << "Could not load icon file '"
+			<< icon_file << "'" << std::endl;
+		return false;
+	}
+
+	video::IImage *img = image_loader->loadImage(icon_f);
+
+	if (!img) {
+		warningstream << "Could not load icon file '"
+			<< icon_file << "'" << std::endl;
+		icon_f->drop();
+		return false;
+	}
+
+	u32 height = img->getDimension().Height;
+	u32 width = img->getDimension().Width;
+
+	size_t icon_buffer_len = 2 + height * width;
+	long *icon_buffer = new long[icon_buffer_len];
+
+	icon_buffer[0] = width;
+	icon_buffer[1] = height;
+
+	for (u32 x = 0; x < width; x++) {
+		for (u32 y = 0; y < height; y++) {
+			video::SColor col = img->getPixel(x, y);
+			long pixel_val = 0;
+			pixel_val |= (u8)col.getAlpha() << 24;
+			pixel_val |= (u8)col.getRed() << 16;
+			pixel_val |= (u8)col.getGreen() << 8;
+			pixel_val |= (u8)col.getBlue();
+			icon_buffer[2 + x + y * width] = pixel_val;
+		}
+	}
+
+	img->drop();
+	icon_f->drop();
+
+	const video::SExposedVideoData &video_data = v_driver->getExposedVideoData();
+
+	Display *x11_dpl = (Display *)video_data.OpenGLLinux.X11Display;
+
+	if (x11_dpl == NULL) {
+		warningstream << "Could not find x11 display for setting its icon."
+			<< std::endl;
+		delete [] icon_buffer;
+		return false;
+	}
+
+	Window x11_win = (Window)video_data.OpenGLLinux.X11Window;
+
+	Atom net_wm_icon = XInternAtom(x11_dpl, "_NET_WM_ICON", False);
+	Atom cardinal = XInternAtom(x11_dpl, "CARDINAL", False);
+	XChangeProperty(x11_dpl, x11_win,
+		net_wm_icon, cardinal, 32,
+		PropModeReplace, (const unsigned char *)icon_buffer,
+		icon_buffer_len);
+
+	delete [] icon_buffer;
+
+	return true;
+#endif
+}
 
 ////
 //// Video/Display Information (Client-only)

src/porting.h

@@ -367,6 +367,9 @@ inline const char *getPlatformName()
 void setXorgClassHint(const video::SExposedVideoData &video_data,
 	const std::string &name);
 
+bool setXorgWindowIcon(IrrlichtDevice *device,
+	const std::string &icon_file);
+
 // This only needs to be called at the start of execution, since all future
 // threads in the process inherit this exception handler
 void setWin32ExceptionHandler();