added App::focused and System::open_url apis

src/app.cpp

@@ -274,6 +274,11 @@ void App::fullscreen(bool enabled)
 	Platform::set_fullscreen(enabled);
 }
 
+bool App::focused()
+{
+	return Platform::get_focused();
+}
+
 Renderer App::renderer()
 {
 	return Graphics::renderer();
@@ -284,6 +289,11 @@ const RendererFeatures& Blah::App::renderer_features()
 	return Graphics::features();
 }
 
+void System::open_url(const char* url)
+{
+	Platform::open_url(url);
+}
+
 namespace
 {
 	// A dummy Frame Buffer that represents the Back Buffer

src/filesystem.cpp

@@ -146,5 +146,10 @@ FilePath Path::normalize(const FilePath& path)
 
 FilePath Path::join(const FilePath& a, const FilePath& b)
 {
-	return normalize(FilePath(a).append("/").append(b));
+	if (a.length() <= 0)
+		return normalize(b);
+	else if (b.length() <= 0)
+		return normalize(a);
+	else
+		return normalize(FilePath(a).append("/").append(b));
 }

src/internal/platform.h

@@ -43,6 +43,9 @@ namespace Blah
 		// Sets the Application Window Position, in Screen Coordinates
 		void set_position(int x, int y);
 
+		// Gets whether the Window has focus
+		bool get_focused();
+
 		// Sets the Window Fullscreen if enabled is not 0
 		void set_fullscreen(bool enabled);
 
@@ -102,5 +105,8 @@ namespace Blah
 
 		// D3D11 Methods
 		void* d3d11_get_hwnd();
+
+		// Tries to open a URL in a web browser
+		void open_url(const char* url);
 	}
 }

src/internal/platform_sdl2.cpp

@@ -494,6 +494,12 @@ void Platform::set_position(int x, int y)
 	SDL_SetWindowPosition(g_platform.window, x, y);
 }
 
+bool Platform::get_focused()
+{
+	auto flags = SDL_GetWindowFlags(g_platform.window);
+	return (flags & SDL_WINDOW_INPUT_FOCUS) != 0 && (flags & SDL_WINDOW_MINIMIZED) == 0;
+}
+
 void Platform::set_fullscreen(bool enabled)
 {
 	if (enabled)
@@ -768,4 +774,9 @@ void* Platform::d3d11_get_hwnd()
 #endif
 }
 
+void Platform::open_url(const char* url)
+{
+	SDL_OpenURL(url);
+}
+
 #endif // BLAH_PLATFORM_SDL2