To test your project during development, you can preview it by clicking the "play" icon in the main toolbar, by selecting , by right-clicking a layout in the Project Bar and selecting Preview, or by pressing F5. This will start your game from the current layout.
By default, starting a preview opens a popup window. You may see a message that the popup was blocked. Clicking Try again normally works, but to permanently prevent the message appearing you may need to change your browser's settings. Usually an icon or message will appear somewhere in the browser interface indicating a popup was blocked; clicking this usually provides a way to always allow popups for the current website.
, you can choose different preview modes. The three options are:
- Popup window: as described above, opens a popup window to run the project in.
- Browser tab: opens a new browser tab to run the project in.
- Dialog: opens a dialog inside the Construct interface to run the project in. This does not use a new browser window so is not subject to popup blockers, and does not include other browser interface items like the address bar. However it cannot appear larger than, or outside of, the Construct window.
If you select Preview again with a preview already running, the existing preview window or dialog will restart and begin previewing the latest version of your project.
Multiple preview windows
Sometimes it's useful to have multiple simultaneous preview windows open, such as for testing multiplayer games. To open an additional preview window, hold Alt while clicking the preview button, or use the Alt + 4 or Alt + 5 keyboard shortcuts to start an additional preview of the project or layout, respectively.
Other preview types
In the main toolbar, there is a dropdown arrow next to the Preview button that shows a menu with more preview options. These can also be found in the
submenu, or by right-clicking the project name in the Project Bar.
This runs the current layout in a special debug mode. The debugger is a special development tool which helps you inspect the state of the project (such as the value of expressions and variables). It also provides diagnostic tools such as advancing the game frame-by-frame, changing values, destroying objects, setting breakpoints in events, and more. This can bring invaluable insight to how your project is working, particularly if you run in to a problem. For more information see the manual section on the Debugger.
This starts a preview from the first layout in the project. This is either the first layout that appears in the Project Bar, or whichever layout is set in the First layout project property.
Paid plans only This allows you to preview your project on a different device. It is also useful for testing different browsers on the same device. Starting a Remote Preview does not actually directly run your game. It will open a dialog that provides a special URL you can use to load the game, or a QR code to scan. All you need to do is open the URL on another browser or device, or share the URL with someone else, or scan the QR code, and the project will start to load and run in the browser. The project is loaded directly from your device using a peer-to-peer connection; it is not uploaded anywhere else, but is still accessible from anywhere on the Internet. The game is no longer available from the provided URL as soon as you close the Remote Preview dialog. You can open the Remote Preview dialog to its own window to help keep it out of the way, by right-clicking on its caption and selecting .
Once the project starts running, they appear in the Remote Preview dialog as a connected client. You can have multiple copies of the project running simultaneously.
You can view some basic system details and real-time performance information for connected clients, including their browser & OS, which layout they are on, the framerate and approximate CPU usage (and approximate GPU usage if available), and their graphics hardware. You can also click Request video to see a video stream of what that client can see. There is also a dropdown to choose a different first layout in case you want to test a specific layout with Remote Preview.
Like with a normal preview, you can update a remote preview by selecting the Remote preview option again. This updates the version of the project available at the same URL. Existing clients will be notified of an update and will see the update if they manually reload. Alternatively clicking the Reload all button will force all clients to reload.
Clients who are viewing your project via Remote Preview will see notifications in the following situations:
- When the host updates the project, clients will see a notification indicating an update is available. They must reload their browser to load the new version.
- When the host closes the Remote Preview dialog, the remote preview ends. Clients will see a notification that the host disconnected. Clients can continue to run the project (they are not cut off), but if they reload the project will no longer be available.
- When the host starts or stops video the client will be notified.
Remote Preview allows you to instantly share your project to anyone in the world with an Internet connection. This is particularly useful if you have remote testers or reviewers. On the other hand you can use the remote preview URL on the same device for cross-browser testing, such as using Remote Preview to test your project in Firefox while Construct runs in Chrome. In this case data is not sent over the Internet and is only transferred across the local system. Similarly if you Remote Preview to a device on the same local area network (LAN), such as a mobile device, most browsers will try to establish a local connection for data transfer ensuring the project can load at a much faster LAN speed rather than transferring via the Internet.