Hi everyone,
Does anyone know how I can rotate a skybox so it matches the position of my directional light?
I don’t want to animate it just rotate it into the correct position. It’s important that it matches the directional light rather than the other way around.
I’m using the included “DawnDusk Skybox”
Thanks in advance,
Max
+1
This is something that I wonder since long time why no engine allows a parameter of skybox rotation.
It should be so easy to do, I think, and so useful!
I place the light with the right direction only to find then that I have to rerender the skybox or make another one entirely because I can’t adjust the original one.
I found myself again recently in the same condition. Luckily I have my solution to create skyboxes in Max very easily so it wasn’t a problem but I guess not everybody has the knowledge or time to do this so an option to rotate the skybox would be definitely useful.
Maybe I’m missing something but since the skybox is composed of separate images right left etc. why don’t you just copy the images into the orientation you want and rotate the overhead one?
Probably because he (like me) needs finer tuning than 90 degrees 
After all, the skybox, for what I know, is really a geometry box so why not allow to draw it rotated respect to the cam?
You can swap out each front/back/etc but it’s not giving the position I want.
Why not fake a skybox instead?
You should now have a fake Skybox. If you want to rotate the skybox by itself, you can just rotate the GameObject.
Yeah that’s the first solution I thought of, Screenhog, thank you anyway, but the best solution, seeing that we already have a skybox built-in Unity, would be from them to add this option, right?
This was my solution to the problem.
I make my skybox Unity way.
then make an GameObject to put all my components in the scene in including my cam.
Now I can rotate that object and the skybox background changes but the game setup is still the same.
you may have to change the scrips to handle this rotation.
Hang on, there is a much simpler solution than this. It’s always best to use the built in stuff if you can, and in this case it’s not too hard.
Heres what you can do:
Good luck!
public class SkyboxCamera : MonoBehaviour {
// set the main camera in the inspector
public Camera MainCamera;
// set the sky box camera in the inspector
public Camera SkyCamera;
// the additional rotation to add to the skybox
// can be set during game play or in the inspector
public Vector3 SkyBoxRotation;
// Use this for initialization
void Start()
{
if (SkyCamera.depth >= MainCamera.depth)
{
Debug.Log("Set skybox camera depth lower "+
" than main camera depth in inspector");
}
if (MainCamera.clearFlags != CameraClearFlags.Nothing)
{
Debug.Log("Main camera needs to be set to dont clear" +
"in the inspector");
}
}
// if you need to rotate the skybox during gameplay
// rotate the skybox independently of the main camera
public void SetSkyBoxRotation(Vector3 rotation)
{
this.SkyBoxRotation = rotation;
}
// Update is called once per frame
void Update()
{
SkyCamera.transform.position = MainCamera.transform.position;
SkyCamera.transform.rotation = MainCamera.transform.rotation;
SkyCamera.transform.Rotate(SkyBoxRotation);
}
}
With some modifications to his script, scottm361’s solution worked for me, thanks to the detailed guide. Thanks.
scottm361’s solution worked for me after commenting a few lines.
// Update is called once per frame
void Update ()
{
SkyCamera.transform.Rotate (SkyBoxRotation);
}
I had to make a update function like this to make it work (Space.World)
public function LateUpdate() : void
{
transform.position = parentTransform.position;
transform.rotation = parentTransform.rotation;
transform.Rotate ( 0.00, skyRotation, 0.00, Space.World);
}
also some tips;
I replaced transform with rTransform and added in awake rTransform = transform;
I renamed lateupdate() and call it from my actual camera script that provides the position and rotation to the function.
When using Deferred lighting, this does not seem to work,
the skybox won’t render, and if i change the camera witch has the depth only from deferred to forward it works.
Bug?
Also the skybox only cam can be set to vertex lit for performance or does this not matter?
You could create a skybox shader for this purpose
Skybox.shader
Shader "World/Skybox"
{
Properties
{
_Brightness("Brightness", Range(0,1)) = .5
_MainTex("Stars", Cube) = "white" {}
}
SubShader
{
Tags { "Queue" = "Background" }
Pass
{
ZWrite Off
Cull Off
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
float _Brightness;
float4x4 _SkyboxRotation;
#include "UnityCG.cginc"
struct vertexInput
{
float4 vertex : POSITION;
float3 texcoord : TEXCOORD0;
};
struct vertexOutput
{
float4 vertex : SV_POSITION;
float4 vertexWorld : POSITION1;
float3 texcoord : TEXCOORD0;
};
vertexOutput vert(vertexInput _input)
{
vertexOutput output;
output.vertex = mul(UNITY_MATRIX_MVP, mul(_SkyboxRotation,-_input.vertex));
output.texcoord = -_input.texcoord;
output.vertexWorld = mul(_Object2World, -_input.vertex);
return output;
}
fixed4 frag(vertexOutput _input) : COLOR
{
return texCUBE(_StarsText, _input.texcoord);
}
ENDCG
}
}
}
This code rotate an skybox, but only from Y axis:
void Update () {
RenderSettings.skybox.SetFloat(“_Rotation”, Time.time * adjustment);
}
This shader will let you rotate a skybox in any direction. It will rotate with Light0.
Shader "Custom/MovingSkyboxUpload" {
Properties {
_CubeMap ("Skybox Cube Map", Cube) = "" {}
}
SubShader {
Pass{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
uniform samplerCUBE _CubeMap;
struct vertexInput{
float4 vertex: POSITION;
};
struct vertexOutput{
float4 pos : SV_POSITION;
float4 posWorld : TEXCOORD1;
fixed3x3 R : TEXCOORD4;
};
vertexOutput vert(vertexInput v){
vertexOutput o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.posWorld = mul(_Object2World, v.vertex);
fixed3 new_up = normalize(_WorldSpaceLightPos0.xyz);
// folowing code from http://stackoverflow.com/questions/32257338/vertex-position-relative-to-normal
float3 up = float3(0,1,0);
float3 w = cross(up, new_up);
float s = length(w); // Sine of the angle
float c = dot(up, new_up); // Cosine of the angle
float3x3 VX = float3x3 (
0, -1 * w.z, w.y,
w.z, 0, -1 * w.x,
-1 * w.y, w.x, 0
); // This is the skew-symmetric cross-product matrix of v
float3x3 I = float3x3 (
1, 0, 0,
0, 1, 0,
0, 0, 1
); // The identity matrix
o.R = I + VX + mul(VX , VX) * (1 - c)/(s*s); // The rotation matrix! YAY!
// previous code from http://stackoverflow.com/questions/32257338/vertex-position-relative-to-normal
return o;
}
float4 frag(vertexOutput i) : COLOR{
float3 viewDirection = normalize( _WorldSpaceCameraPos.xyz - i.posWorld.xyz );
viewDirection = mul (viewDirection , i.R);
return texCUBE(_CubeMap, viewDirection);
}
ENDCG
}
}
}
Built in Unity5.2.1
Thanks Demol, that was exactly what I needed
I know this thread’s been running for a while, but here’s a real simple way to do it:
Do the double camera set-up as scottm 361 explained above, but then put this simple script on the SkyboxCam :
void FixedUpdate (){
transform.Rotate (0, rotation speed, 0);
}
Works great and hardly any typing at all.
Nic,
Your shader works well but it only seems to rotate the skybox about 2 axes. “Z” has no effect.
Strangely, the main camera y and z rotation have exactly the same effect.
Help please.