declare shader
    struct { integer "prim_index" }
        "c_tessellate_store" ()
    version 1
    apply texture
end declare

declare shader
    "c_tessellate_contrast" ()
    version 1
    apply texture
end declare

declare shader
    "c_tessellate_contour" (
        color "color" default 0 0 0 1,
        scalar "width" default 1
    )
    version 1
    apply texture
end declare