urho3d/SourceAssets/Shaders/Basic.xml

<shaders>
    <shader name="Basic" type="vs">
        <option name="Diff" define="DIFFMAP" />
        <option name="VCol" define="VERTEXCOLOR" />
    </shader>
    <shader name="Basic" type="ps">
        <option name="Diff" define="DIFFMAP" exclude="Alpha" />
        <option name="Alpha" define="ALPHAMAP" exclude="Diff" />
        <option name="VCol" define="VERTEXCOLOR" />
    </shader>
    <shader name="Skybox" />
</shaders>