原理:
_Clip-i.uv.y 用于区分是否显示MainTex,获得裁剪值
step 对 裁剪值 进行比较,如果结果为1不显示RGB
mc*(1-y) 从上到下显示MainTex
tc*(y) 从裁剪位置向下显示TwoTex
Shader "Custom/ClipTexture"
{
Properties
{
_Color ("Color", Color) = (1,1,1,1)
_MainTex ("Texture", 2D) = "white" {}
_TwoTex("TwoTex (RGB)", 2D)= "white" {}
_Clip("Clip",Range(0,1))=1.0
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
};
half _Clip;
sampler2D _MainTex;
sampler2D _TwoTex;
float4 _MainTex_ST;
fixed4 _Color;
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
fixed4 mc = tex2D (_MainTex, i.uv) * _Color;
fixed4 tc = tex2D (_TwoTex, i.uv) * _Color;
half y = step(0, _Clip-i.uv.y);
fixed4 col = mc*(1-y) + tc*(y);
return col;
}
ENDCG
}
}
}