Shader "Skybox/LatLong"
{
    Properties
    {
        [NoScaleOffset] _MainTexture ("Main Texture (LatLong)", 2D) = "white" {}
    }
    SubShader 
    {
        Tags { "Queue"="Background" "RenderType"="Background" "PreviewType"="Skybox" }
        Cull Off ZWrite Off

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"
            #include "Lighting.cginc"

            sampler2D _MainTexture;

            struct appdata_t
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4  pos             : SV_POSITION;
                float3  vertex          : TEXCOORD0;
            };

            v2f vert (appdata_t v)
            {
                v2f OUT;
                OUT.pos = UnityObjectToClipPos(v.vertex);

                // Get the ray from the camera to the vertex and its length (which is the far point of the ray passing through the atmosphere)
                float3 eyeRay = normalize(mul((float3x3)unity_ObjectToWorld, v.vertex.xyz));
                OUT.vertex = -eyeRay;

                return OUT;
            }

            float2 GetLatLongCoords(float3 normalizedViewDir)
            {
                float lon = atan2(-normalizedViewDir.x, -normalizedViewDir.z);
                float lat = asin(-normalizedViewDir.y);

                float2 uv;

                uv.x = (lon / (2.0 * UNITY_PI)) + 0.5;

                uv.y = ((lat / UNITY_PI) + 0.5);
                uv.y = saturate((uv.y - 0.5) / 0.5);

                return uv;
            }

            half4 frag (v2f IN) : SV_Target
            {
                half3 viewDir = normalize(IN.vertex.xyz);

                half2 coords = GetLatLongCoords(viewDir);

                half4 col = tex2Dlod(_MainTexture, half4(coords, 2, 0));

                return col;
            }

            ENDCG
        }
    }
}

    Shader "Skybox/LatLong"
{
    Properties
    {
        [NoScaleOffset] _MainTexture ("Main Texture (LatLong)", 2D) = "white" {}
    }
    SubShader 
    {
        Tags { "Queue"="Background" "RenderType"="Background" "PreviewType"="Skybox" }
        Cull Off ZWrite Off

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"
            #include "Lighting.cginc"

            sampler2D _MainTexture;

            struct appdata_t
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4  pos             : SV_POSITION;
                float3  vertex          : TEXCOORD0;
            };

            v2f vert (appdata_t v)
            {
                v2f OUT;
                OUT.pos = UnityObjectToClipPos(v.vertex);

                // Get the ray from the camera to the vertex and its length (which is the far point of the ray passing through the atmosphere)
                float3 eyeRay = normalize(mul((float3x3)unity_ObjectToWorld, v.vertex.xyz));
                OUT.vertex = -eyeRay;

                return OUT;
            }

            half2 GetLatLongCoords(float3 normalizedViewDir)
            {
                half lon = atan2(-normalizedViewDir.x, -normalizedViewDir.z);
                half lat = asin(-normalizedViewDir.y);

                half2 uv;

                uv.x = (lon / (2.0 * UNITY_PI)) + 0.5;

                uv.y = ((lat / UNITY_PI) + 0.5);
                uv.y = saturate((uv.y - 0.5) / 0.5);

                return uv;
            }

            half4 frag (v2f IN) : SV_Target
            {
                half3 viewDir = normalize(IN.vertex.xyz);

                half2 coords = GetLatLongCoords(viewDir);

                half4 col = tex2Dlod(_MainTexture, half4(coords, 2, 0));

                return col;
            }

            ENDCG
        }
    }
}