2019-07-19 【shader】简易版局域校色

Shader "Unlit/lasttest"
{
    Properties
    {
        _MainTex("Texture", 2D) = "white" {}
        _GrayTex("GrayTexture", 2D) = "white" {}

        
        _Color255("Color255", Color) = (1, 1, 1)
        _Color214("Color200", Color) = (1, 1, 1)
        _Color137("Color111", Color) = (1, 1, 1)
        _Color71("Color35", Color) = (1, 1, 1)


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

            Pass
            {
                CGPROGRAM
                #pragma vertex vert
                #pragma fragment frag

                #include "UnityCG.cginc"

                struct appdata
                {
                    float4 vertex : POSITION;
                    float2 uv : TEXCOORD0;
                };

                struct v2f
                {
                    float4 vertex : SV_POSITION;
                    float2 uv : TEXCOORD0;
                    float4 worldPos : TEXCOORD1;
                };

                sampler2D _MainTex;
                float4 _MainTex_ST;

                sampler2D _GrayTex;
                float4 _GrayTex_ST;

                fixed3 _Color255;
                fixed3 _Color214;
                fixed3 _Color137;
                fixed3 _Color71;



                // RGB 转 HSV
                //float3 RGB2HSV(float3 c)
                //{
                //  float4 K = float4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
                //  float4 p = lerp(float4(c.bg, K.wz), float4(c.gb, K.xy), step(c.b, c.g));
                //  float4 q = lerp(float4(p.xyw, c.r), float4(c.r, p.yzx), step(p.x, c.r));

                //  float d = q.x - min(q.w, q.y);
                //  float e = 1.0e-10;
                //  return float3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
                //}


                v2f vert(appdata v)
                {
                    v2f o;
                    o.vertex = UnityObjectToClipPos(v.vertex);
                    o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                    o.worldPos = mul(unity_ObjectToWorld, v.vertex);

                    return o;
                }

                fixed4 frag(v2f i) : SV_Target
                {
                    // sample the texture
                    fixed4 col = tex2D(_MainTex, i.uv);
                    fixed4 sss = tex2D(_GrayTex, i.uv);

                    float realR = sss.r * 255;

                    if (realR <= 72)
                    {
                        col.xyz = _Color71;
                    }
                    else if (realR <= 138)
                    {
                        col.xyz = _Color137;
                    }
                    else if (realR <= 215)
                    {
                        col.xyz = _Color214;
                    }
                    else
                    {
                        col.xyz = _Color255;
                    }


                    //float 


                    //fixed3 _Color255;
                    //fixed3 _Color214;
                    //fixed3 _Color137;
                    //fixed3 _Color71;



                    //else col.xyz *= _Color35;

                    return col;
                }

                ENDCG
            }
        }
}