How to scroll a texture in a shader?

Questions & Answers
1

I’m having trouble on figuring out how to scroll a texture in a surface shader. What I’m trying to make is a surface shader that has both rim lighting (which is implemented) and has a texture which scrolls around the object it’s on. This is my shader up to now:

Shader "Custom/StarShader" {
	Properties{
	_Color("Color", Color) = (1,1,1,1)
	_MainTex("Texture", 2D) = "white" {}
	_SubTex("Texture", 2D) = "white" {}
	_RimColor("Rim Color", Color) = (0.26,0.19,0.16,0.0)
	_RimPower("Rim Power", Range(0.1,2.0)) = 3.0
	_ScrollXSpeed("X", Range(0,10)) = 2
	_ScrollYSpeed("Y", Range(0,10)) = 3

	}
		SubShader{
		Tags{ "RenderType" = "Opaque" }
		CGPROGRAM
#pragma surface surf Lambert
	struct Input {
		float2 uv_MainTex;
		float2 uv_SubTex;
		float3 viewDir;
		fixed _ScrollXSpeed;
		fixed _ScrollYSpeed;
	};
	sampler2D _MainTex;
	sampler2D _SubTex;
	float4 _RimColor;
	float _RimPower;
	fixed4 _Color;

	void surf(Input IN, inout SurfaceOutput o) {
		fixed2 scrolledUV = IN.uv_MainTex;

		fixed xScrollValue = _ScrollXSpeed * _Time;
		fixed yScrollValue = _ScrollYSpeed * _Time;

		scrolledUV += fixed2(xScrollValue, yScrollValue);
		half4 c = tex2D(_MainTex, scrolledUV);

		o.Albedo = tex2D(_MainTex, IN.uv_MainTex).rgb;
		o.Albedo += c.rbg;

		half rim = 1.0 - saturate(dot(normalize(IN.viewDir), o.Normal));
		o.Emission = _RimColor.rgb * pow(rim, _RimPower);
	}
	ENDCG
	}
		Fallback "Diffuse"
}

I simply want to find a way on how to scroll the texture around the object via a shader. I’m getting multiple “Undefined variable” errors trying it this way.

2

You are defining _ScrollXSpeed and _ScrollYSpeed inside the input struct. simply remove it from there and put them after closing the struct.

#pragma surface surf Lambert
struct Input {
float2 uv_MainTex;
float2 uv_SubTex;
float3 viewDir;
};
sampler2D _MainTex;
sampler2D _SubTex;
float4 _RimColor;
float _RimPower;
fixed4 _Color;
fixed _ScrollXSpeed;
fixed _ScrollYSpeed;