struct vtf
    {
        float4 position: SV_POSITION;
        float2 uv: TEXCOORD0;
    };
    float4 _DirLightDirection;
    vtf vert(appdata_Shadow v)
    {
        vtf i;
        float3 normal = normalize(_DirLightDirection);
        float3 tangent = VerticalBillboardTangent(normal);
        float4 ShadowCastPos = VerticalBillboardWorld(v.vertex, normal, tangent);
        float4 ShadowCastClipPos = mul(unity_MatrixVP, ShadowCastPos);

        float3 cameraNormal = VerticalBillboardNormal(_WorldSpaceCameraPos);
        float3 cameraTangent = VerticalBillboardTangent(cameraNormal);
        float4 cameraWorld = VerticalBillboardWorld(v.vertex, cameraNormal, cameraTangent);


        //replace wPos with cameraWorld
        float4 wPos = ShadowCastPos;
        if (unity_LightShadowBias.z != 0.0)
        {
            //replace normal with cameraNormal to get camera facing shadows
            float3 wNormal = UnityObjectToWorldNormal(normal);
            float3 wLight = normalize(UnityWorldSpaceLightDir(wPos.xyz));

            float shadowCos = dot(wNormal, wLight);
            float shadowSine = sqrt(1 - shadowCos * shadowCos);
            float normalBias = unity_LightShadowBias.z * shadowSine;

            wPos.xyz -= wNormal * normalBias;
        }
        i.position = mul(UNITY_MATRIX_VP, wPos);

        //This is the original
        //i.position = UnityClipSpaceShadowCasterPos(ShadowCastClipPos);

        i.position = UnityApplyLinearShadowBias(i.position);
        i.uv = v.uv;
        return i;
    }

    half4 frag(vtf v): SV_TARGET
    {
        //clip(tex2D(_MainTex, v.uv).a - 0.5);
        return 0;
    }
float3 VerticalBillboardNormal(float3 target)
{
    return normalize(target - mul(unity_ObjectToWorld, float4(0, 0, 0, 1)).xyz);
}
float3 VerticalBillboardTangent(float3 normal){
    return cross(normal, float3(0, 1, 0));
}

float4 VerticalBillboardWorld(float4 vertex, float3 normal, float3 tangent)
{
    float yawCamera = atan2(tangent.x, normal.x) - UNITY_PI / 2;//Add 90 for quads to face towards camera
    float s, c;
    sincos(yawCamera, s, c);

    float3x3 transposed = transpose((float3x3)unity_ObjectToWorld);
    float3 scale = float3(length(transposed[0]), length(transposed[1]), length(transposed[2]));

    float3x3 newBasis = float3x3(
        float3(c * scale.x, 0, s * scale.z),
        float3(0, scale.y, 0),
        float3(-s * scale.x, 0, c * scale.z)
    );//Rotate yaw to point towards camera, and scale by transform.scale

    float4x4 objectToWorld = unity_ObjectToWorld;
    //Overwrite basis vectors so the object rotation isn't taken into account
    objectToWorld[0].xyz = newBasis[0];
    objectToWorld[1].xyz = newBasis[1];
    objectToWorld[2].xyz = newBasis[2];
    //Now just normal MVP multiply, but with the new objectToWorld injected in place of matrix M
    return mul(objectToWorld, vertex);

    // worldPos = mul(objectToWorld, vertex).xyz;
    // return mul(UNITY_MATRIX_VP, mul(objectToWorld, vertex));
}
float4 VerticalBillboard(float3 target, float4 vertex)
{
    float3 normal = VerticalBillboardNormal(target);
    float3 tangent = VerticalBillboardTangent(normal);
    float4 world = VerticalBillboardWorld(vertex, normal, tangent);
    return mul(UNITY_MATRIX_VP, world);
}