# DisplayFlow IDD Driver Integration Guide

## Overview
To achieve a true "Virtual Display" (where Windows thinks a monitor is connected but it's just software), we need to compile and install a **User-Mode Driver Framework (UMDF) Indirect Display Driver (IDD)**.

We will use the **Microsoft Indirect Display Driver Sample** as a base and modify it to send frames to our shared memory.

## Prerequisites
1.  **Visual Studio 2019/2022** with "Desktop development with C++".
2.  **Windows Driver Kit (WDK)** compatible with your VS version.
    *   Download: [https://learn.microsoft.com/en-us/windows-hardware/drivers/download-the-wdk](https://learn.microsoft.com/en-us/windows-hardware/drivers/download-the-wdk)

## Steps

### 1. Download the Sample
Clone the Windows Driver Samples repository:
```bash
git clone https://github.com/microsoft/Windows-driver-samples.git
cd video/IndirectDisplay/IddCxMonitorDriver
```

### 2. Integrate DisplayFlow Code
Copy the following files from `demo/windows_driver/src/` to the driver project folder (`IddCxMonitorDriver`):
*   `IddProducer.h`
*   `IddProducer.cpp`

### 3. Modify Project Settings
1.  Open the solution `IddCxMonitorDriver.sln` in Visual Studio.
2.  Right-click project -> **Add** -> **Existing Item** -> Select `IddProducer.h` and `IddProducer.cpp`.
3.  Ensure `IddProducer.cpp` is not using precompiled headers (Right-click file -> Properties -> C/C++ -> Precompiled Headers -> **Not Using Precompiled Headers**).

### 4. Modify `IndirectDevice.cpp` (or `SwapChainProcessor.cpp`)
Find the logic where the driver processes frames. In the sample, this is typically in the `SwapChainProcessor` class (or inside `IndirectDevice::Run`).

1.  **Include Header**:
    ```cpp
    #include "IddProducer.h"
    ```

2.  **Add Member**:
    Add `IddProducer m_Producer;` to the class that handles the swap chain.

3.  **Initialize**:
    In the initialization phase (before the loop):
    ```cpp
    m_Producer.Initialize();
    ```

4.  **Process Frame**:
    Inside the frame loop, after acquiring the `ID3D11Texture2D*` (Surface), map it and submit it.
    *   *Note*: The surface from `IddCx` is usually not CPU readable. You must copy it to a **Staging Texture** first.
    *   Refer to `demo/windows_driver/src/SwapChainProcessor_Example.cpp` for the logic.

### 5. Build and Install
1.  Build the solution (Platform: x64, Configuration: Release).
2.  Locate the output files (`.dll`, `.inf`, `.cat`).
3.  **Install Certificate**: The driver is self-signed. You must install the test certificate to `Trusted Root Certification Authorities` and `Trusted Publishers`.
4.  **Install Driver**:
    *   Open Device Manager.
    *   Action -> Add legacy hardware.
    *   Install from Disk -> Point to `.inf` file.
    *   Select "IddCx Monitor Driver".

### 6. Verification
Once installed, Windows should show a new display. `DisplayFlow` sender (Consumer) should automatically pick up the frames from the Shared Memory (if running with `--source=idd`).