stk-code/data/shaders/sps_03_decal.xml

<spshader>
    <shader-info name="decal"/>
    <first-pass vertex-shader="sp_pass.vert"
        fragment-shader="sp_decal.frag" skinned-mesh-shader="sp_skinning.vert">
    </first-pass>
    <shadow-pass vertex-shader="sp_shadow.vert" fragment-shader="white.frag"
        skinned-mesh-shader="sp_skinning_shadow.vert">
    </shadow-pass>
    <uniform-assigners>
        <uniform-assigner name="layer"
        function="shadowCascadeUniformAssigner"/>
    </uniform-assigners>
</spshader>