Unity3d窗体透明

点击打开链接偶然在网站上看到的一个脚本，通过纯色背景抠像的方法，把windows的窗体透明化，可以用来做无背景的小头像、桌面精灵等。

首先新建一个叫TransparentWindow的CS脚本，输入如下代码：

using System;using System.Runtime.InteropServices;using UnityEngine;public class TransparentWindow : MonoBehaviour{    [SerializeField]    private Material m_Material;    private struct MARGINS    {        public int cxLeftWidth;        public int cxRightWidth;        public int cyTopHeight;        public int cyBottomHeight;    }    // Define function signatures to import from Windows APIs    [DllImport("user32.dll")]    private static extern IntPtr GetActiveWindow();    [DllImport("user32.dll")]    private static extern int SetWindowLong(IntPtr hWnd, int nIndex, uint dwNewLong);    [DllImport("Dwmapi.dll")]    private static extern uint DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS margins);    // Definitions of window styles    const int GWL_STYLE = -16;    const uint WS_POPUP = 0x80000000;    const uint WS_VISIBLE = 0x10000000;    void Start()    {#if !UNITY_EDITOR        var margins = new MARGINS() { cxLeftWidth = -1 };        // Get a handle to the window        var hwnd = GetActiveWindow();        // Set properties of the window        // See: https://msdn.microsoft.com/en-us/library/windows/desktop/ms633591%28v=vs.85%29.aspx</span>        SetWindowLong(hwnd, GWL_STYLE, WS_POPUP | WS_VISIBLE);        // Extend the window into the client area        //See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa969512%28v=vs.85%29.aspx         DwmExtendFrameIntoClientArea(hwnd, ref margins);#endif    }    // Pass the output of the camera to the custom material    // for chroma replacement    void OnRenderImage(RenderTexture from, RenderTexture to)    {        Graphics.Blit(from, to, m_Material);    }}

然后新建一个叫ChromakeyTransparent的Shader：

Shader "Custom/ChromakeyTransparent" {    Properties{        _MainTex("Base (RGB)", 2D) = "white" {}        _TransparentColourKey("Transparent Colour Key", Color) = (0,0,0,1)        _TransparencyTolerance("Transparency Tolerance", Float) = 0.01    }    SubShader{        Pass{            Tags{ "RenderType" = "Opaque" }            LOD 200            CGPROGRAM            #pragma vertex vert            #pragma fragment frag            #include "UnityCG.cginc"            struct a2v            {                float4 pos : POSITION;                float2 uv : TEXCOORD0;            };            struct v2f            {                float4 pos : SV_POSITION;                float2 uv : TEXCOORD0;            };            v2f vert(a2v input)            {                v2f output;                output.pos = UnityObjectToClipPos(input.pos);                output.uv = input.uv;                return output;            }            sampler2D _MainTex;            float3 _TransparentColourKey;            float _TransparencyTolerance;            float4 frag(v2f input) : SV_Target            {                // What is the colour that would be rendered here?                float4 colour = tex2D(_MainTex, input.uv);                // Calculate the different in each component from the chosen transparency colour                float deltaR = abs(colour.r - _TransparentColourKey.r);                float deltaG = abs(colour.g - _TransparentColourKey.g);                float deltaB = abs(colour.b - _TransparentColourKey.b);                // If colour is within tolerance, write a transparent pixel                if (deltaR < _TransparencyTolerance && deltaG < _TransparencyTolerance && deltaB < _TransparencyTolerance)                {                    return float4(0.0f, 0.0f, 0.0f, 0.0f);                }                // Otherwise, return the regular colour                return colour;            }            ENDCG        }    }}<ul class="pre-nng" ""="" 
新建一个材质，选择我们刚刚写好的Shader，将TransparentWindow挂载到摄像机上，摄像机的Clear Flags选择Solid Color，Background选择和材质的Transparent Color Key相同的颜色（建议选择与模型边缘颜色相近的颜色，不然会出现较明显的毛边），将材质拖拽给TransparentWindow的Material变量。 
运行之后可以看到背景颜色已经被扣掉（黑色其实是透明）： 
Build一下之后我们就可以看到类似桌面精灵的一个程序了： 
已经做好的地址http://download.csdn.net/download/jingtiang/10020139