CreateFileSystemWatcher

This function can be used to create an object that monitors a specified directory for changes.

Syntax

• shared_ptr<FileSystemWatcher> CreateFileSystemWatcher(const WString& path, const bool recursive = true)

Returns

Returns a new FileSystemWatcher object if the specified directory exists, otherwise NULL is returned.

Remarks

Once the FileSystemWatcher object is created, it will monitor the directory to detect changes. When changes occur an event will be emitted. The event ID will be one of the following

• EVENT_FILECREATE
• EVENT_FILEDELETE
• EVENT_FILERENAME
• EVENT_FILECHANGE

Example

#include "UltraEngine.h"

using namespace UltraEngine;

//---------------------------------------------------------------------------------------------------
// This example demonstrates use of a FileSystemWatcher to allow dynamic asset reloading.
// Run the example and modify the image file in a paint program to see your changes appear as the program is running.
//---------------------------------------------------------------------------------------------------

int main(int argc, const char* argv[])
{
    // Get the primary display
    auto displaylist = GetDisplays();
    auto display = displaylist[0];

    // Create a window
    auto window = CreateWindow("Ultra Engine", 0, 0, 1280, 720, display, WINDOW_TITLEBAR | WINDOW_CENTER);

    // Download the texture file
    auto path = GetPath(PATH_DOCUMENTS) + "/Temp";
    CreateDir(path);
    CopyFile("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Materials/Ground/dirt01.jpg", path + "/dirt01.jpg");
    OpenDir(path + "/dirt01.jpg");

    //Create FileSystemWatcher to detect changes to files
    auto watcher = CreateFileSystemWatcher(path);

    auto plugin = LoadPlugin("Plugins/FITextureLoader");
    auto ui = CreateInterface(window);
    auto panel = CreatePanel(0, 0, window->ClientSize().x, window->ClientSize().y, ui->root);
    panel->SetPixmap(LoadPixmap(path + "/dirt01.jpg"));

    // Main loop
    while (window->Closed() == false)
    {
        //Check for file change events
        auto e = WaitEvent();

        //Look for file change or create events. Some programs delete the file and then recreate it when they save.
        if (e.id == EVENT_FILECHANGE or e.id == EVENT_FILECREATE)
        {
            //Look for a loaded asset with this file path
            auto asset = FindCachedAsset(e.text);
            if (asset)
            {
                //Reload the modified asset
                asset->Reload();
                panel->Redraw();
            }
        }
    }
    return 0;
}