NGUI 图片变灰

效果图

1、先准备好一个变灰shader。代码如下

Shader "Custom/Gray"
{
	Properties
	{
		_MainTex ("Base (RGB), Alpha (A)", 2D) = "black" {}
	}

	SubShader
	{
		LOD 200

		Tags
		{
			"Queue" = "Transparent"
			"IgnoreProjector" = "True"
			"RenderType" = "Transparent"
		}

		Pass
		{
			Cull Off
			Lighting Off
			ZWrite Off
			Fog { Mode Off }
			Offset -1, -1
			Blend SrcAlpha OneMinusSrcAlpha

			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#include "UnityCG.cginc"

			sampler2D _MainTex;
			float4 _MainTex_ST;

			struct appdata_t
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
				fixed4 color : COLOR;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
				half2 texcoord : TEXCOORD0;
				fixed4 color : COLOR;
			};

			v2f o;

			v2f vert (appdata_t v)
			{
				o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
				o.texcoord = v.texcoord;
				o.color = v.color;
				return o;
			}

			fixed4 frag (v2f IN) : COLOR
			{
				float4 col =tex2D(_MainTex, IN.texcoord) * IN.color;
				float grey = dot(col.rgb, float3(0.299, 0.587, 0.114));
                col.rgb = float3(grey, grey, grey); 

				return col;
			}
			ENDCG
		}
	}

	SubShader
	{
		LOD 100

		Tags
		{
			"Queue" = "Transparent"
			"IgnoreProjector" = "True"
			"RenderType" = "Transparent"
		}

		Pass
		{
			Cull Off
			Lighting Off
			ZWrite Off
			Fog { Mode Off }
			Offset -1, -1
			ColorMask RGB
			Blend SrcAlpha OneMinusSrcAlpha
			ColorMaterial AmbientAndDiffuse

			SetTexture [_MainTex]
			{
				Combine Texture * Primary
			}
		}
	}
}

2、制作一个atlas图集prefab

　　在Project里选择几个纹理右键->Open Atlas Maker->New->Create

3、修改prefab材质

　　点击刚刚生成的atlas图集prefab->Material->导航到Project中我们刚生成的atlas图集prefab所使用的材质->把shader改成Custom/Cray(这个shader就是我们上面那个shader的名字)

4、设置到UISprite下看看