Rotation of Texture/UVs directly from a shader

Don’t use a surface shader. Right click in the project view and create a new unlit shader. You can copy the contents of the above vert function into the start of the vertex shader (in addition to what’s already there), change texcoord to uv, and you’re done.

 

That made it look just like the shader I want, but there's no rotation.

Code (CSharp):

1. Shader "Unlit/rotatingUNLIT"
2. {
3.     Properties
4.     {
5.         _MainTex ("Texture", 2D) = "white" {}
6.         _RotationSpeed ("Rotation Speed", Float) = 2.0
7.     }
8.     SubShader
9.     {
10.         Tags { "RenderType"="Transparent" }
11.         LOD 100
12.  
13.         ZWrite Off
14.         Blend SrcAlpha OneMinusSrcAlpha
15.  
16.         Pass
17.         {
18.             CGPROGRAM
19.             #pragma vertex vert
20.             #pragma fragment frag
21.             // make fog work
22.             #pragma multi_compile_fog
23.            
24.             #include "UnityCG.cginc"
25.  
26.             struct appdata
27.             {
28.                 float4 vertex : POSITION;
29.                 float2 uv : TEXCOORD0;
30.             };
31.  
32.             struct v2f
33.             {
34.                 float2 uv : TEXCOORD0;
35.                 UNITY_FOG_COORDS(1)
36.                 float4 vertex : SV_POSITION;
37.             };
38.  
39.             sampler2D _MainTex;
40.             float4 _MainTex_ST;
41.             struct Input {
42.                 float2 uv_MainTex;
43.             };
44.            
45.             float _RotationSpeed;
46.            
47.             v2f vert (appdata v)
48.             {
49.                 v2f o;
50.                 o.vertex = UnityObjectToClipPos(v.vertex);
51.                 o.uv = TRANSFORM_TEX(v.uv, _MainTex);
52.                 UNITY_TRANSFER_FOG(o,o.vertex);
53.                 v.uv.xy -=0.5;
54.                 float s = sin ( _RotationSpeed * _Time );
55.                 float c = cos ( _RotationSpeed * _Time );
56.                 float2x2 rotationMatrix = float2x2( c, -s, s, c);
57.                 rotationMatrix *=0.5;
58.                 rotationMatrix +=0.5;
59.                 rotationMatrix = rotationMatrix * 2-1;
60.                 v.uv.xy = mul ( v.uv.xy, rotationMatrix );
61.                 v.uv.xy += 0.5;
62.                 return o;
63.             }
64.            
65.             fixed4 frag (v2f i) : SV_Target
66.             {
67.                 // sample the texture
68.                 fixed4 col = tex2D(_MainTex, i.uv);
69.                 // apply fog
70.                 UNITY_APPLY_FOG(i.fogCoord, col);
71.                 return col;
72.             }
73.        
74.             ENDCG
75.         }
76.     }
77. }
78.  

 

You're modifying v.uv after it's already been copied to o.uv, which is the actual value that gets passed from the vertex to the fragment. This means the rotation is ignored. Move that to the top of the vertex function, or at least before the "o.uv =" line. Alternatively change v.uv to o.uv in the code handling the rotation.

 

how would i be able to apply this to one texture on a shader with multiple textures?