Add instructions

osu.Game.Resources/Fonts/README.md

@@ -0,0 +1,26 @@
+# How to create binary font files
+
+There are two options:
+
+## When generating
+
+When using the official BMFont generator, there is a setting in "Export Options" that specifies the output file format. Just set that to "binary" to get the correct file format. Remember to use the file extension ".bin".
+
+## Converting existing fonts
+
+```csharp
+using SharpFNT;
+
+string filename = "MyFont.fnt";
+
+var font = BitmapFont.FromFile(filename);
+
+// This value is ignored for Unicode fonts, but serializing will fail
+// if this is empty so just set it to ANSI (0 in binary)
+if (font.Info.Charset == string.Empty)
+{
+    font.Info.Charset = "ANSI";
+}
+
+font.Save(Path.ChangeExtension(filename, "bin"), FormatHint.Binary);
+```

osu.Game.Resources/osu.Game.Resources.csproj

@@ -14,4 +14,7 @@
     <EmbeddedResource Include="Textures\**\*" />
     <EmbeddedResource Include="Tracks\**\*" />
   </ItemGroup>
+  <ItemGroup>
+    <Content Include="Fonts\README.md" />
+  </ItemGroup>
 </Project>