shader——uv动画水波纹

Shader "Custom/BigFishShader"
{
	Properties
	{
		_MainTex("Texture", 2D) = "white" {}
		_SubTex("Texture", 2D) = "white" {}//定义一个波纹的tex
	}
	SubShader
	{
		Tags { "RenderType"="Opaque" }
		LOD 100

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 vertex : SV_POSITION;
			};

			sampler2D _MainTex;
			sampler2D _SubTex;//同上，名字必须一致
			float4 _MainTex_ST;
			
			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				return o;
			}
			
			fixed4 frag (v2f i) : SV_Target
			{
				// sample the texture
				float2 offset = float2(0, 0);//设置一个随时间变化的偏移值
				offset.x = _Time.y/5;
				offset.y = _Time.y/5;
				fixed4 light_color = tex2D(_SubTex, i.uv+offset);//根据偏移值改变uv
				fixed4 col = tex2D(_MainTex, i.uv)+light_color;//将两张贴图叠加到一起
				return col;
			}
			ENDCG
		}
	}
}