float3 posWs = mul(unity_ObjectToWorld, v.vertex).xyz;
float3 normWs = mul(unity_ObjectToWorld, v.normal);
float hardY = max(0.0f, posWs.y);
float softY = max(0.2f, posWs.y);
float softBlend = normWs.y + 1.0f;
posWs.y = lerp(hardY, softY, softBlend);
v.vertex.xyz = mul(unity_WorldToObject, float4(posWs, 1.0f)).xyz;