Subsurf.cginc

#define INTERPOLATE(name) \
            o.name = \
            patch[0].name * barycentric.x + \
            patch[1].name * barycentric.y + \
            patch[2].name * barycentric.z;

int subdivisions = 1;

struct v2h
{
    float2 uv : TEXCOORD0;
    float3 normal : NORMAL;
    float4 vertex : SV_POSITION;
};

struct chull
{
    float edges[3] : SV_TessFactor;
    float inside : SV_InsideTessFactor;
};

[UNITY_domain("tri")]
[UNITY_partitioning("integer")]
[UNITY_outputcontrolpoints(3)]
[UNITY_outputtopology("triangle_cw")]
[UNITY_patchconstantfunc("hull_const")]
v2h hull(InputPatch<v2h, 3> patch,
    uint id : SV_OutputControlPointID) {
    v2h o = patch[id];
    return o;
}

chull hull_const(InputPatch<v2h, 3> patch) {
    chull o;
    o.edges[0] = subdivisions;
    o.edges[1] = subdivisions;
    o.edges[2] = subdivisions;
    o.inside = subdivisions;
    return o;
}

[UNITY_domain("tri")]
v2h domain(
    chull factors,
    OutputPatch<v2h, 3> patch,
    float3 barycentric : SV_DomainLocation
) {
    v2h o;
    INTERPOLATE(uv);
    INTERPOLATE(normal);
    INTERPOLATE(vertex);
    return o;
}