【003-Shader-消融特效】

// 消融特效
Shader "Study/03-RemoveShader"
{
    
    
    Properties
    {
    
    
        _MainTex ("Texture", 2D) = "white" {
    
    }
    }
    SubShader
    {
    
    
        // No culling or depth
        Cull Off ZWrite Off ZTest Always
        Blend SrcAlpha OneMinusSrcAlpha

        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;
            };

            v2f vert (appdata v)
            {
    
    
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            sampler2D _MainTex;
            static float3 rate = {
    
    0.3,0.6,0.1};


            /**
            Time.x  = time/8
            Time.y = time/4
            Time.z = time/2 
            Time.w = time
            **/

            fixed4 frag (v2f i) : SV_Target
            {
    
    
                fixed4 col = tex2D(_MainTex, i.uv);
                
                // 获取亮度（灰色）
                fixed gray = dot(rate,col.rgb);

                if(gray - _Time.y<0){
    
    

                    discard;//不显示该像素
                }

                return col;
            }
            ENDCG
        }
    }
}