Unity3D-Shader之两张图片叠加并且通过颜色调控_unity图片叠加

最近项目需要做一个图片叠加在一个模型上，而且还需要通过调整颜色改变两个图片的颜色和透明程度。

另外，还需要一个调控值，管理两张图片是否完全显示，Shader如下：

Shader "Unlit/BlockTextrue"
{
	Properties
	{
		_MainColor ("Main Color", Color) = (1,1,1,1) //前景图颜色
        _BackColor ("Back Color", Color) = (1,1,1,1) //背景图颜色
		_MainTex ("Main Texture", 2D) = "white" {} //前景图
        _BackTex ("Back Texture", 2D) = "white" {} //背景图
        _BackCut ("Back cutoff", Range (0, 1)) = 0//用来调控背景图片显示情况
	}
	SubShader
	{
		Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
		LOD 100
 
		// ZWrite Off
    	// Blend SrcAlpha OneMinusSrcAlpha
 
		Pass
		{
			CGPROGRAM
			#pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0
            #pragma multi_compile_fog
 
            #include "UnityCG.cginc"
 
            struct appdata_t {
                float4 vertex : POSITION;
                float2 texcoord : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };
 
            struct v2f {
                float4 vertex : SV_POSITION;
                float2 texcoord : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                UNITY_VERTEX_OUTPUT_STEREO
            };
 
            sampler2D _MainTex;
            sampler2D _BackTex;
            float4 _MainTex_ST;
			fixed4 _MainColor;
            fixed4 _BackColor;
            float _BackCut;
 
            v2f vert (appdata_t v)
            {
                v2f o;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }
 
            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 backCol = tex2D(_BackTex, i.texcoord)*_BackColor;
                fixed4 texCol = tex2D(_MainTex, i.texcoord)*_MainColor;
                fixed4 col = _BackColor;
                col.rgb = backCol.rgb*(1-_BackCut) + col.rgb*_BackCut;
                col.rgb = col.rgb*(1-texCol.a) + texCol.rgb*texCol.a;
                UNITY_APPLY_FOG(i.fogCoord, col);
                return col;
            }
			ENDCG
		}
	}
}

效果就不弄了，直接Copy直接调就知道了