【每日一记】unity3d 图片置灰shader

项目须要。參考了一下网上的资料，写了一个shader，给button置灰。

shader详细实现例如以下：

2016.07.25补充，支持mask剪裁

Shader "Transparent Colored Gray"

{

Properties

{

_MainTex ("Base (RGB), Alpha (A)", 2D) = "white" {}

_Color ("Tint", Color) = (1,1,1,1)



_StencilComp ("Stencil Comparison", Float) = 8

_Stencil ("Stencil ID", Float) = 0

_StencilOp ("Stencil Operation", Float) = 0

_StencilWriteMask ("Stencil Write Mask", Float) = 255

_StencilReadMask ("Stencil Read Mask", Float) = 255





_ColorMask ("Color Mask", Float) = 15





[Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0

}





SubShader

{

Tags

{ 

"Queue"="Transparent" 

"IgnoreProjector"="True" 

"RenderType"="Transparent" 

"PreviewType"="Plane"

"CanUseSpriteAtlas"="True"

}



Stencil

{

Ref [_Stencil]

Comp [_StencilComp]

Pass [_StencilOp] 

ReadMask [_StencilReadMask]

WriteMask [_StencilWriteMask]

}





Cull Off

Lighting Off

ZWrite Off

ZTest [unity_GUIZTestMode]

Blend SrcAlpha OneMinusSrcAlpha

ColorMask [_ColorMask]





Pass

{

CGPROGRAM

#pragma vertex vert

#pragma fragment frag





#include "UnityCG.cginc"

#include "UnityUI.cginc"





#pragma multi_compile __ UNITY_UI_ALPHACLIP



struct appdata_t

{

float4 vertex   : POSITION;

float4 color    : COLOR;

float2 texcoord : TEXCOORD0;

};





struct v2f

{

float4 vertex   : SV_POSITION;

fixed4 color    : COLOR;

half2 texcoord  : TEXCOORD0;

float4 worldPosition : TEXCOORD1;

};



fixed4 _Color;

fixed4 _TextureSampleAdd;

float4 _ClipRect;





v2f vert(appdata_t IN)

{

v2f OUT;

OUT.worldPosition = IN.vertex;

OUT.vertex = mul(UNITY_MATRIX_MVP, OUT.worldPosition);





OUT.texcoord = IN.texcoord;



#ifdef UNITY_HALF_TEXEL_OFFSET

OUT.vertex.xy += (_ScreenParams.zw-1.0)*float2(-1,1);

#endif



OUT.color = IN.color * _Color;

return OUT;

}





sampler2D _MainTex;





fixed4 frag(v2f IN) : SV_Target

{

// Sample the texture

half4 color = tex2D(_MainTex, IN.texcoord) * IN.color;

float c = 0.299*color.r + 0.587*color.g + 0.184*color.b;

color.r = color.g = color.b = c;

color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);

#ifdef UNITY_UI_ALPHACLIP

clip (color.a - 0.001);

#endif





return color;

}

ENDCG

}

}

}

先建一个名为colorGrayMat的材质，把shader文件附加到材质上。

管理material材质代码：

public class MaterialManager

{

    public static void addMaterial(Image img, string materialName)

    {

        Material material = GameAssets.instance.loadMaterial(materialName);

        if (img != null && material != null)

        {

            img.material = material;

        }

    }

public static void addGrayMaterial(Image img)

    {

        addMaterial(img,"colorGrayMat");

    }

}

调用代码：

MaterialManager.addGrayMaterial(img);

关于shader资料：

官网资料： http://docs.unity3d.com/Manual/SL-SurfaceShaders.html（英文）

http://unity3d.9tech.cn/news/2013/1220/39315.html（中文）

猫都能学会的Unity3D Shader入门指南 http://www.onevcat.com/2013/07/shader-tutorial-1/