Reading texture in vertex shader of a surface shader?

Unity Engine
1

I added a vertex shader to my simple surface shader:

#pragma surface surf Standard fullforwardshadows vertex:vert

sampler2D _HeightMap;

void vert(inout appdata_full v) {
     fixed4 wsr = tex2D(_HeightMap, ???); // What to do here?
     v.vertex.y += wsr.r + wsr.g + wsr.b;
}

I want to read a texture, and change the y coordinate depending its value. However I can’t find how to do it.

How can I do this?

2

Found it:

void vert(inout appdata_full v) {
fixed4 wsr = tex2Dlod(_WaterSandRock, v.texcoord); // ← notice “tex2Dlod” and “v.texcoord”
v.vertex.y += wsr.r + wsr.g + wsr.b;
}