Unity -Demo 之 ✨桌面小宠物

看到网上有用Unity做的桌面小宠物，就自己搜了些资料自己做了一个小Demo。

具体步骤如下：

简单说一下思路，有一个脚本跟一个Shader，通过脚本和Shader负责将Unity运行时的背景调成透明色。这个是通过调颜色来进行了。具体原理也不清楚，查了查资料大概是这样

一、首先是代码部分：

shader:

Shader "Custom/MakeTransparent" {
  Properties {
    _MainTex ("Base (RGB)", 2D) = "white" {}
    _TransparentColorKey ("Transparent Color Key", Color) = (0,1,0,1)
    _TransparencyMargin ("Transparency Margin", Float) = 0.01 
  }
  SubShader {
    Pass {
      Tags { "RenderType"="Opaque" }
      LOD 200
    
      CGPROGRAM

      #pragma vertex VertexShaderFunction
      #pragma fragment PixelShaderFunction
    
      #include "UnityCG.cginc"

      struct VertexData
      {
        float4 position : POSITION;
        float2 uv : TEXCOORD0;
      };

      struct VertexToPixelData
      {
        float4 position : SV_POSITION;
        float2 uv : TEXCOORD0;
      };

      VertexToPixelData VertexShaderFunction(VertexData input)
      {
        VertexToPixelData output;
        output.position = UnityObjectToClipPos (input.position);
        output.uv = input.uv;
        return output;
      }
    
      sampler2D _MainTex;
      float3 _TransparentColorKey;
      float _TransparencyMargin;

      float4 PixelShaderFunction(VertexToPixelData input) : SV_Target
      {
        float4 color = tex2D(_MainTex, input.uv);
      
        float deltaR = abs(color.r - _TransparentColorKey.r);
        float deltaG = abs(color.g - _TransparentColorKey.g);
        float deltaB = abs(color.b - _TransparentColorKey.b);

        if (deltaR < _TransparencyMargin && deltaG < _TransparencyMargin && deltaB < _TransparencyMargin)
        {
          return float4(0.0f, 0.0f, 0.0f, 0.0f);
        }

        return color;
      }
      ENDCG
    }
  }
}
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C#:

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;
    }

    [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);

    [DllImport("user32.dll", EntryPoint = "SetWindowPos")]
    private static extern int SetWindowPos(IntPtr hwnd, IntPtr hwndInsertAfter, int x, int y, int cx, int cy,
        int uFlags);

    [DllImport("user32.dll")]
    static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);

    [DllImport("user32.dll", EntryPoint = "SetLayeredWindowAttributes")]
    static extern int SetLayeredWindowAttributes(IntPtr hwnd, int crKey, byte bAlpha, int dwFlags);

    [DllImport("User32.dll")]
    private static extern bool SetForegroundWindow(IntPtr hWnd);

    const int GWL_STYLE = -16;
    const int GWL_EXSTYLE = -20;
    const uint WS_POPUP = 0x80000000;
    const uint WS_VISIBLE = 0x10000000;

    const uint WS_EX_TOPMOST = 0x00000008;
    const uint WS_EX_LAYERED = 0x00080000;
    const uint WS_EX_TRANSPARENT = 0x00000020;

    const int SWP_FRAMECHANGED = 0x0020;
    const int SWP_SHOWWINDOW = 0x0040;
    const int LWA_ALPHA = 2;

    private IntPtr HWND_TOPMOST = new IntPtr(-1);

    private IntPtr _hwnd;

    void Start()
    {
#if !UNITY_EDITOR
    MARGINS margins = new MARGINS() { cxLeftWidth = -1 };
    _hwnd = GetActiveWindow();
    int fWidth = Screen.width;
    int fHeight = Screen.height;
        SetWindowLong(_hwnd, GWL_STYLE, WS_POPUP | WS_VISIBLE);
        //SetWindowLong(_hwnd, GWL_EXSTYLE, WS_EX_TOPMOST | WS_EX_LAYERED | WS_EX_TRANSPARENT);//若想鼠标穿透，则将这个注释恢复即可
        DwmExtendFrameIntoClientArea(_hwnd, ref margins);
        SetWindowPos(_hwnd, HWND_TOPMOST, 0, 0, fWidth, fHeight, SWP_FRAMECHANGED | SWP_SHOWWINDOW); 
        ShowWindowAsync(_hwnd, 3); //Forces window to show in case of unresponsive app    // SW_SHOWMAXIMIZED(3)
#endif
    }

    void OnRenderImage(RenderTexture from, RenderTexture to)
    {
        Graphics.Blit(from, to, m_Material);
    }
}

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二、具体步骤

1.新建一个material(材质球),选择刚建立的Shader:

2.将刚写的C#脚本挂在摄像机上，摄像机的Clear Flags模式选择Solod Color，并将刚建立的材质球挂在脚本上。3.摄像机的Background属性要和材质球的Transparent Color Key属性一致：

4.这里要注意一个点，unity19以上的版本需要设置一个东西。在playerSetting中将这个UseDXGIFlipModelSwapchainforD3D11取消勾选。

这样就可以实现窗口透明了，然后在场景里加一个模型跟动作就好啦