struct Plane
{
    float4 nd;
    float3 getNormal()
    {
        return nd.xyz;
    }
    float getDistance()
    {
        return nd.w;
    }
    bool pointInside(float3 point)
    {
        return dot(getNormal(), point) - getDistance() > 0.0f;
    }
};

struct Frustum
{
    Plane sides[4];
    bool pointInside(float3 point)
    {
        for(int p = 0; p < 4; ++p)
        {
            if(!sides[p].pointInside(point))
            {
                return false;
            }
        }
        return true;
    }
};
Plane computePlane(float3 p0, float3 p1, float3 p2)
{
    Plane plane;

    float3 v0 = p1 - p0;
    float3 v2 = p2 - p0;

    float3 n = normalize(cross(v0, v2));

    float d = dot(n, p0);

    plane.nd = float4(n, d);

    return plane;
}