使用Shader制作炫酷的死亡溶解效果

前段时间在开发RPG游戏时用到了Shader怪物死亡溶解特效，所以在这里介绍下用法；

效果图:

贴图设置：

Shader代码

Shader "MyShader/Dissolve"
{
	Properties{
		_Diffuse("Diffuse", Color) = (1,1,1,1)
		_DissolveColor("Dissolve Color", Color) = (0,0,0,0)
		_DissolveEdgeColor("Dissolve Edge Color", Color) = (1,1,1,1)
		_MainTex("Base 2D", 2D) = "white"{}
	_DissolveMap("DissolveMap", 2D) = "white"{}
	_DissolveThreshold("DissolveThreshold", Range(0,1)) = 0
		_ColorFactor("ColorFactor", Range(0,1)) = 0.7
		_DissolveEdge("DissolveEdge", Range(0,1)) = 0.8
	}

		CGINCLUDE
#include "Lighting.cginc"
		uniform fixed4 _Diffuse;
	uniform fixed4 _DissolveColor;
	uniform fixed4 _DissolveEdgeColor;
	uniform sampler2D _MainTex;
	uniform float4 _MainTex_ST;
	uniform sampler2D _DissolveMap;
	uniform float _DissolveThreshold;
	uniform float _ColorFactor;
	uniform float _DissolveEdge;

	struct v2f
	{
		float4 pos : SV_POSITION;
		float3 worldNormal : TEXCOORD0;
		float2 uv : TEXCOORD1;
	};

	v2f vert(appdata_base v)
	{
		v2f o;
		o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
		o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
		o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);
		return o;
	}
	//v.vertex.xyz += v.normal * _DissolveThreshold * 0.5;
	fixed4 frag(v2f i) : SV_Target
	{
		//采样Dissolve Map
		fixed4 dissolveValue = tex2D(_DissolveMap, i.uv);
	//小于阈值的部分直接discard
	if (dissolveValue.r < _DissolveThreshold)
	{
		discard;
	}
	//Diffuse + Ambient光照计算
	fixed3 worldNormal = normalize(i.worldNormal);
	fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
	fixed3 lambert = saturate(dot(worldNormal, worldLightDir));
	fixed3 albedo = lambert * _Diffuse.xyz * _LightColor0.xyz + UNITY_LIGHTMODEL_AMBIENT.xyz;
	fixed3 color = tex2D(_MainTex, i.uv).rgb * albedo;
	float percentage = _DissolveThreshold / dissolveValue.r;
	//当前百分比 - 颜色权重 - 边缘颜色
	float lerpEdge = sign(percentage - _ColorFactor - _DissolveEdge);
	//貌似sign返回的值还得saturate一下，否则是一个很奇怪的值
	fixed3 edgeColor = lerp(_DissolveEdgeColor.rgb, _DissolveColor.rgb, saturate(lerpEdge));
	//最终输出颜色的lerp值
	float lerpOut = sign(percentage - _ColorFactor);
	//最终颜色在原颜色和上一步计算的颜色之间差值（其实经过saturate（sign（..））的lerpOut应该只能是0或1）
	fixed3 colorOut = lerp(color, edgeColor, saturate(lerpOut));
	
	return fixed4(colorOut, 1);
	}
		ENDCG

		SubShader
	{
		Tags{ "RenderType" = "Opaque" }
			Pass
		{
			CGPROGRAM
#pragma vertex vert
#pragma fragment frag	
			ENDCG
		}
	}
	FallBack "Diffuse"


}

参考链接：http://m.blog.csdn.net/puppet_master/article/details/72455945