selfshadow

float Beckmann1(float3 n, float3 h, float m)
{
    float ndoth = saturate(dot(n, h));
    float cos2 = ndoth*ndoth;
    return exp((cos2 - 1)/(cos2*m*m));
}

// mul r0.x, cb0[2].x, cb0[2].x
// dp3_sat r0.y, cb0[0].xyzx, cb0[1].xyzx
// mul r0.z, r0.y, r0.y

selfshadow

// Blending when n1 and n2 are already 'unpacked' and normalised
float3 blend_rnm_unpacked(float3 n1, float3 n2)
{
    float3 t = n1.xyz + float3( 0,  0, 1);
    float3 u = n2.xyz * float3(-1, -1, 1);
    float3 r = (t/t.z)*dot(t, u) - u;
    return r;
}

selfshadow

struct PS_INPUT 
{
    float4 Pos : VS_OUT_POSITION; 
};

// removing "const" fixes the problem
float4 Function(const float4 value)
{
    return value;
}