如何在Unity中制作透明窗口？现有代码配置运行后未生效求解决方案

前置配置检查 #

• 打开Unity Player设置，进入「Resolution and Presentation」栏，勾选「Allow Transparent Window」（Unity 2021及以上版本提供该选项，旧版本需额外移除窗口边框样式）
• 相机参数确认：清除标志设置为「Solid Color」，背景色设为RGBA(0,0,0,0)，关闭相机HDR功能，禁用深度纹理输出
• 渲染管线配置：将渲染路径设置为Forward，所有需要显示的透明材质需开启Alpha Blend模式，关闭深度写入

代码问题修正 #

你当前的代码缺少窗口扩展样式配置、MARGINS结构定义可能存在错误，调用顺序也不符合DWM透明渲染的要求，修正后的完整代码如下：
首先是正确的Win32 API及结构体声明：

using System;
using System.Runtime.InteropServices;
using UnityEngine;

public struct MARGINS
{
    public int cxLeftWidth;
    public int cxRightWidth;
    public int cyTopHeight;
    public int cyBottomHeight;
}

public static class Win32API
{
    public const int GWL_STYLE = -16;
    public const int GWL_EXSTYLE = -20;
    public const uint WS_CAPTION = 0x00C00000;
    public const uint WS_EX_LAYERED = 0x00080000;
    public const uint WS_EX_TRANSPARENT = 0x00000020;
    public const uint WS_EX_COMPOSITED = 0x02000000;
    public const int LWA_ALPHA = 0x00000002;
    public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
    public const uint SWP_FRAMECHANGED = 0x0020;
    public const uint SWP_SHOWWINDOW = 0x0040;

    [DllImport("user32.dll")]
    public static extern IntPtr GetActiveWindow();

    [DllImport("user32.dll")]
    public static extern uint GetWindowLong(IntPtr hWnd, int nIndex);

    [DllImport("user32.dll")]
    public static extern int SetWindowLong(IntPtr hWnd, int nIndex, uint dwNewLong);

    [DllImport("user32.dll")]
    public static extern bool SetLayeredWindowAttributes(IntPtr hWnd, uint crKey, byte bAlpha, uint dwFlags);

    [DllImport("user32.dll")]
    public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);

    [DllImport("dwmapi.dll")]
    public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMarInset);
}

然后是调用逻辑，建议放在Start生命周期中执行：

void Start()
{
    int fWidth = Screen.width;
    int fHeight = Screen.height;
    var hwnd = Win32API.GetActiveWindow();

    // 移除默认窗口标题栏样式
    uint oldStyle = Win32API.GetWindowLong(hwnd, Win32API.GWL_STYLE);
    uint newStyle = oldStyle & ~Win32API.WS_CAPTION;
    Win32API.SetWindowLong(hwnd, Win32API.GWL_STYLE, newStyle);

    // 添加透明所需的扩展窗口样式
    uint oldExStyle = Win32API.GetWindowLong(hwnd, Win32API.GWL_EXSTYLE);
    uint newExStyle = oldExStyle | Win32API.WS_EX_LAYERED | Win32API.WS_EX_COMPOSITED;
    // 如需鼠标穿透则保留WS_EX_TRANSPARENT，不需要可删除
    // newExStyle |= Win32API.WS_EX_TRANSPARENT;
    Win32API.SetWindowLong(hwnd, Win32API.GWL_EXSTYLE, newExStyle);

    // 扩展DWM玻璃区域到整个窗口
    var margins = new MARGINS() { cxLeftWidth = -1 };
    Win32API.DwmExtendFrameIntoClientArea(hwnd, ref margins);

    // 设置分层窗口属性，这里保留完全不透明的全局alpha，仅使用内容本身的alpha通道
    Win32API.SetLayeredWindowAttributes(hwnd, 0, 255, Win32API.LWA_ALPHA);

    // 应用窗口位置和层级设置
    Win32API.SetWindowPos(hwnd, Win32API.HWND_TOPMOST, 0, 0, fWidth, fHeight, Win32API.SWP_FRAMECHANGED | Win32API.SWP_SHOWWINDOW);
}

额外注意事项 #

• 打包后测试效果，编辑器下运行可能无法正确触发透明效果
• 系统需开启Aero效果（Win7及以上系统默认开启，Win10/11无需额外配置）

内容的提问来源于stack exchange，提问作者warriorforce