【001-Shader-颜色混合】

一、代码内容

代码如下（示例）：

// 颜色混合
Shader "Study/ImageShader1"
{
    
    
    Properties
    {
    
    
        _MainTex ("Main Texture", 2D) = "white" {
    
    }
        _RampTex ("Ramp Texture",2D) = "black"{
    
    }
        _Offset("Ramp Offset",float) = 0
        
        // _ValueW("Value W",fixed) = 0.1 //混合权重
    }
    SubShader
    {
    
    
        // No culling or depth
        Cull Off ZWrite Off ZTest Always
        // 开启透明度混合 color_out = color_src * a + color_bg * (1-a)
        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;
            };

            // 顶点着色器
            v2f vert (appdata v)
            {
    
    
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            sampler2D _MainTex;
            sampler2D _RampTex;
            float _Offset;
            // fixed _ValueW;
   
            // 片元着色器
            fixed4 frag (v2f i) : SV_Target
            {
    
    
                // tex2D:通过UV采样纹理
                fixed4 col = tex2D(_MainTex, i.uv);

                // just invert the colors 负片效果
                // col.rgb = 1 - col.rgb;
                
                fixed4 ramp_col = tex2D(_RampTex,i.uv);
                fixed w = 0.5; 
                col.rgb = col*w + ramp_col*(1 - w);
                return col;
            }
            ENDCG
        }
    }
}