UnityShaderLab-实现溶解效果

实现思路：

使用一张噪声图，与一个Cut值计算（加或减），将计算后的值赋值给Alpha,然后小于0的片段就被丢弃掉了。

ShaderGraph实现：

ShaderLab实现：

Shader "Dissolve"
{Properties{_BaseColor("Color", Color) = (1, 1, 1, 1)_NoisoScale("NoisoScale", Float) = 40_NoiseStrenth("NoiseStrenth", Float) = 3.07_CutoffHeight("CutoffHeight", Range(-10,10)) = 0.12_EdgeWidth("EdgeWidth", Range(0,0.5)) = -0.03[HDR]_EdgeColor("EdgeColor", Color) = (1, 0.8352941, 0, 0)}SubShader{Tags {"RenderType"="Transparent"}Blend SrcAlpha OneMinusSrcAlphaPass{CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"float Unity_SimpleNoise_RandomValue_float (float2 uv){float angle = dot(uv, float2(12.9898, 78.233));return frac(sin(angle)*43758.5453);}float Unity_SimpleNnoise_Interpolate_float (float a, float b, float t){return (1.0-t)*a + (t*b);}void Remap_float(float In, float2 InMinMax, float2 OutMinMax, out float Out){Out = OutMinMax.x + (In - InMinMax.x) * (OutMinMax.y - OutMinMax.x) / (InMinMax.y - InMinMax.x);}void Negate_float(float In, out float Out){Out = -1 * In;}float SimpleNoise_ValueNoise_float (float2 uv){float2 i = floor(uv);float2 f = frac(uv);f = f * f * (3.0 - 2.0 * f);uv = abs(frac(uv) - 0.5);float2 c0 = i + float2(0.0, 0.0);float2 c1 = i + float2(1.0, 0.0);float2 c2 = i + float2(0.0, 1.0);float2 c3 = i + float2(1.0, 1.0);float r0 = Unity_SimpleNoise_RandomValue_float(c0);float r1 = Unity_SimpleNoise_RandomValue_float(c1);float r2 = Unity_SimpleNoise_RandomValue_float(c2);float r3 = Unity_SimpleNoise_RandomValue_float(c3);float bottomOfGrid = Unity_SimpleNnoise_Interpolate_float(r0, r1, f.x);float topOfGrid = Unity_SimpleNnoise_Interpolate_float(r2, r3, f.x);float t = Unity_SimpleNnoise_Interpolate_float(bottomOfGrid, topOfGrid, f.y);return t;}void SimpleNoise_float(float2 UV, float Scale, out float Out){float t = 0.0;float freq = pow(2.0, float(0));float amp = pow(0.5, float(3-0));t += SimpleNoise_ValueNoise_float(float2(UV.x*Scale/freq, UV.y*Scale/freq))*amp;freq = pow(2.0, float(1));amp = pow(0.5, float(3-1));t += SimpleNoise_ValueNoise_float(float2(UV.x*Scale/freq, UV.y*Scale/freq))*amp;freq = pow(2.0, float(2));amp = pow(0.5, float(3-2));t += SimpleNoise_ValueNoise_float(float2(UV.x*Scale/freq, UV.y*Scale/freq))*amp;Out = t;}struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;};struct v2f{float2 uv : TEXCOORD0;float4 vertex : SV_POSITION;float4 posWS: TEXCOORD1;};float _NoisoScale;float _NoiseStrenth;float _CutoffHeight;float _EdgeWidth;float4 _EdgeColor;float4 _BaseColor;v2f vert (appdata v){v2f o;o.vertex = UnityObjectToClipPos(v.vertex);o.posWS = mul(unity_ObjectToWorld, v.vertex);o.uv = v.uv;return o;}fixed4 frag (v2f i) : SV_Target{float outNoise;SimpleNoise_float(i.uv,_NoisoScale,outNoise);float newStrenth;Negate_float(_NoiseStrenth,newStrenth);float finalNoise;Remap_float(outNoise,float2(0,1),float2(newStrenth,_NoiseStrenth),finalNoise);finalNoise = finalNoise + _CutoffHeight;float3 color = step(finalNoise,i.posWS.y + _EdgeWidth) * _EdgeColor; float alpha = step(i.posWS.y,finalNoise);return fixed4(_BaseColor + color.xyz,alpha) ;}ENDCG}}
}

效果：