模型溶解shader

Shader "Unlit/WaterEffect"
{
Properties {
_Diffuse("Diffuse", Color) = (1,1,1,1)
_MainTex("Base 2D", 2D) = "white"{}
_DissolveMap("DissolveMap", 2D) = "white"{}
_DissolveThreshold("DissolveThreshold", Range(0,1)) = 0
_DissolveColorA("Dissolve Color A", Color) = (0,0,0,0)
_DissolveColorB("Dissolve Color B", Color) = (1,1,1,1)
_ColorFactorA("ColorFactorA", Range(0,1)) = 0.7
_ColorFactorB("ColorFactorB", Range(0,1)) = 0.8
}
SubShader {

Tags{"RenderType" = "Opaque"}
LOD 100

Pass
{
CGPROGRAM

#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"

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

sampler2D _MainTex;
float4 _MainTex_ST;
fixed4 _Diffuse;
sampler2D _DissolveMap;
float _DissolveThreshold;
fixed4 _DissolveColorA;
fixed4 _DissolveColorB;
uniform float _ColorFactorA;
uniform float _ColorFactorB;

v2f vert (appdata_base v)
{
v2f o;
o.uv = TRANSFORM_TEX(v.texcoord,_MainTex);
o.vertex = UnityObjectToClipPos(v.vertex);
return o;
}

fixed4 frag(v2f i): Sv_Target
{
fixed4 dissolveValue = tex2D(_DissolveMap,i.uv);
if(dissolveValue.r < _DissolveThreshold)
{
discard;
}
fixed3 color = tex2D(_MainTex, i.uv);
float lerpValue = _DissolveThreshold / dissolveValue.r;
float lerpEdge = sign(lerpValue - _ColorFactorA * 0.5 - _ColorFactorB * 0.5);
fixed3 edgeColor = lerp(_DissolveColorB.rgb,_DissolveColorA.rgb,saturate(lerpEdge));//边缘颜色，lerpEdge是-1显示B颜色，1显示A颜色
float lerpOut = sign(lerpValue - _ColorFactorA);//判断是否需要显示过渡颜色（A,B颜色）
fixed3 colorOut = lerp(color,edgeColor,saturate(lerpOut));

return fixed4(colorOut, 1);
}
ENDCG
}