test kbd evt optional

hw3d/App.cpp

@@ -21,6 +21,23 @@ int App::Go()
 
 void App::DoFrame()
 {
+	static std::string title;
+	while( const auto e = wnd.kbd.ReadKey() )
+	{
+		if( e->IsPress() && e->GetCode() == VK_BACK )
+		{
+			title.clear();
+			wnd.SetTitle( title );
+		}
+	}
+	while( const auto c = wnd.kbd.ReadChar() )
+	{
+		if( *c != 0x8 ) // don't print backspace
+		{
+			title += *c;
+			wnd.SetTitle( title );
+		}
+	}
 	const float c = sin( timer.Peek() ) / 2.0f + 0.5f;
 	wnd.Gfx().ClearBuffer( c,c,1.0f );
 	wnd.Gfx().DrawTestTriangle();