
CGPROGRAM
// Physically based Standard lighting model, and enable shadows on all light types
#pragma surface surf Standard fullforwardshadows vertex:vert
struct Input {
float2 uv_MainTex;
float3 worldPos;
float4 modelPos_;
};
void vert(inout appdata_full v, out Input o)
{
UNITY_INITIALIZE_OUTPUT(Input, o);
o.modelPos_ = v.vertex;
} ENDCG
float lat = degrees(acos(IN.modelPos_.y / _R));//[0,180]