Unity skybox 6-sided with arbitrary rotation axis

Skybox6-ArbitraryRotation

 // Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
 // Edited from Unity built-in, copied rotation function from here: http://www.neilmendoza.com/glsl-rotation-about-an-arbitrary-axis/
 Shader "Skybox/6 Sided - Arbitrary Rotation" {
 Properties {
     _Tint ("Tint Color", Color) = (.5, .5, .5, .5)
     [Gamma] _Exposure ("Exposure", Range(0, 8)) = 1.0
     _Rotation ("Rotation", Range(0, 360)) = 0
     _RotationAxis("Rotation axis", Vector) = (0, 1, 0)
     [NoScaleOffset] _FrontTex ("Front [+Z]   (HDR)", 2D) = "grey" {}
     [NoScaleOffset] _BackTex ("Back [-Z]   (HDR)", 2D) = "grey" {}
     [NoScaleOffset] _LeftTex ("Left [+X]   (HDR)", 2D) = "grey" {}
     [NoScaleOffset] _RightTex ("Right [-X]   (HDR)", 2D) = "grey" {}
     [NoScaleOffset] _UpTex ("Up [+Y]   (HDR)", 2D) = "grey" {}
     [NoScaleOffset] _DownTex ("Down [-Y]   (HDR)", 2D) = "grey" {}
 }
 
 SubShader {
     Tags { "Queue"="Background" "RenderType"="Background" "PreviewType"="Skybox" }
     Cull Off ZWrite Off
 
     CGINCLUDE
     #include "UnityCG.cginc"
 
     half4 _Tint;
     half _Exposure;
     float _Rotation;
     float3 _RotationAxis;
 
     float3 RotateAroundYInDegrees (float3 vertex, float degrees)
     {
         float alpha = degrees * UNITY_PI / 180.0;
         float sina, cosa;
         sincos(alpha, sina, cosa);
         float2x2 m = float2x2(cosa, -sina, sina, cosa);
         return float3(mul(m, vertex.xz), vertex.y).xzy;
     }
     float4x4 rotationMatrix(float3 axis, float angle)
     {
         axis = normalize(axis);
         float s = sin(angle);
         float c = cos(angle);
         float oc = 1.0 - c;
         
         return float4x4(oc * axis.x * axis.x + c,           oc * axis.x * axis.y - axis.z * s,  oc * axis.z * axis.x + axis.y * s,  0.0,
                     oc * axis.x * axis.y + axis.z * s,  oc * axis.y * axis.y + c,           oc * axis.y * axis.z - axis.x * s,  0.0,
                     oc * axis.z * axis.x - axis.y * s,  oc * axis.y * axis.z + axis.x * s,  oc * axis.z * axis.z + c,           0.0,
                     0.0,                                0.0,                                0.0,                                1.0);
     }
 
     struct appdata_t {
         float4 vertex : POSITION;
         float2 texcoord : TEXCOORD0;
         UNITY_VERTEX_INPUT_INSTANCE_ID
     };
     struct v2f {
         float4 vertex : SV_POSITION;
         float2 texcoord : TEXCOORD0;
         UNITY_VERTEX_OUTPUT_STEREO
     };
     v2f vert (appdata_t v)
     {
         v2f o;
         UNITY_SETUP_INSTANCE_ID(v);
         UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
         //float3 rotated = RotateAroundYInDegrees(v.vertex, _Rotation);
         float3 rotated = mul( rotationMatrix( normalize(_RotationAxis.xyz), _Rotation * UNITY_PI / 180.0), v.vertex).xyz;
         o.vertex = UnityObjectToClipPos(rotated);
         o.texcoord = v.texcoord;
         return o;
     }
     half4 skybox_frag (v2f i, sampler2D smp, half4 smpDecode)
     {
         half4 tex = tex2D (smp, i.texcoord);
         half3 c = DecodeHDR (tex, smpDecode);
         c = c * _Tint.rgb * unity_ColorSpaceDouble.rgb;
         c *= _Exposure;
         return half4(c, 1);
     }
     ENDCG
 
     Pass {
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma target 2.0
         sampler2D _FrontTex;
         half4 _FrontTex_HDR;
         half4 frag (v2f i) : SV_Target { return skybox_frag(i,_FrontTex, _FrontTex_HDR); }
         ENDCG
     }
     Pass{
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma target 2.0
         sampler2D _BackTex;
         half4 _BackTex_HDR;
         half4 frag (v2f i) : SV_Target { return skybox_frag(i,_BackTex, _BackTex_HDR); }
         ENDCG
     }
     Pass{
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma target 2.0
         sampler2D _LeftTex;
         half4 _LeftTex_HDR;
         half4 frag (v2f i) : SV_Target { return skybox_frag(i,_LeftTex, _LeftTex_HDR); }
         ENDCG
     }
     Pass{
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma target 2.0
         sampler2D _RightTex;
         half4 _RightTex_HDR;
         half4 frag (v2f i) : SV_Target { return skybox_frag(i,_RightTex, _RightTex_HDR); }
         ENDCG
     }
     Pass{
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma target 2.0
         sampler2D _UpTex;
         half4 _UpTex_HDR;
         half4 frag (v2f i) : SV_Target { return skybox_frag(i,_UpTex, _UpTex_HDR); }
         ENDCG
     }
     Pass{
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma target 2.0
         sampler2D _DownTex;
         half4 _DownTex_HDR;
         half4 frag (v2f i) : SV_Target { return skybox_frag(i,_DownTex, _DownTex_HDR); }
         ENDCG
     }
 }
 }
 

Thank you

Much appreciated! ☺