While Tiberian Sun includes support for running at reasonably modern resolutions, there are limits to its compatibility (ie. 1440p will crash) and the games presentation becomes unusably small.

When running the game in Windowed Mode it is possible to configure the game to run at resolution where the interface is still usable (ie. 720p), and then use an application like Magpie[github.com] to upscale the window to your full desktop resolution.

The examples in this guide will upscale the game from 1280x720 to 2560x1440.

This guide will use the terms target resolution to refer to your desktop resolution, and source resolution to refer to the resolution that the game will run at in windowed mode.

Integer scaling means that each pixel in the the source resolution will be evenly scaled, resulting in a clean and sharp output at your target resolution. In ideal circumstances you can scale to the full height and width of your target resolution, but in cases where this is not possible you will see borders around the image.

When choosing the source resolution that you intend to scale up from, you need to think about the limitations of the game (ie. at what resolution does the interface become unusable, or the game crash) and what resolution you will be scaling to.

In my testing Tiberian Sun runs reasonably well at a resolution of 1280x720. This resolution will conveniently integer scale up to a 1440p or 4k target resolution, making it an ideal candidate.

You can use this website[scalefactor.pages.dev] to assist with finding resolutions that will scale well to your target resolution.

We need to configure Tiberian Sun to enable support for windowed mode, along with enabling it to see our source resolution.

Ordinarily windowed mode requires your desktop to be running in 16bit colours, but the version of the game on Steam uses DDrawCompat[github.com] and this can trick the game into thinking we are using this.

Open Steam and select the game. Click the gear icon -> Manage -> Browse local files.


An Explorer window will open in the games installation directory.


Locate DDrawCompat.ini and open it in Notepad.

Add the following line to the bottom of the file to enable windowed mode to work correctly:

Locate the line with SupportedResolutions, and edit this to include your source resolution - in this example 1280x720.

Alternatively, you can comment this line out by placing a # at the start. Doing this will then present all available resolutions to the game.


Save the file and close Notepad.


This step is required to enable the game to see higher resolutions. If you are intending to use one of the stock resolutions as your source resolution then you can skip this step.

Locate SUN.INI and open it in Notepad.

Scroll through the file to locate the [Video] section. Add the following line directly beneath the [Video] entry.

Save the file and close Notepad.


Back in Steam with the game selected, click the gear icon -> Properties.

On the general tab, at the bottom enter the following launch option:


The game is now ready to launch in windowed mode.

Magpie[github.com] is an open source scaling tool, which can take almost any Windows application window and then scale it to your preference. For this to work Magpie must be left running when you play the game.

Download the latest release of Magpie from https://github.com/Blinue/Magpie/releases/latest

Extract the zip file and run Magpie.exe.

Magpie includes several preconfigured scaling configurations. We need to add a new one using the Nearest scaling effect that is configured with an appropriate scaling factor.

Our source resolution is 1280x720 and our target resolution is 2560x1440, so we need a scaling factor of 2 (1440 / 720 = 2).

As it happens, Magpie includes an Integer Scale 2x as one of it's pre-sets so you don't actually have to create one in this instance.

However for the benefit of the guide, if the source resolution was 1280x720 and the target resolution is 3840x2160 then we would need a scaling factor of 3.

To create an integer Scaling configuration for this, click Scaling configuration, scroll to the bottom and click New scaling mode. Enter a name like Integer Scale 3x, and select to copy from the existing Integer Scale 2x.


The newly created configuration will appear at the bottom of the list. Click the arrow on the right to expand it, and then click the diagonal arrows to open the settings.


Change the width and height scaling options to 3.

• You can use this website[scalefactor.pages.dev] to assist with finding resolutions that will scale well to your target resolution
  
• Always use the same scaling factor for both the width and height

With everything prepared, the game is now ready to launch.

Start Magpie and then launch Tiberian Sun from Steam.

The game should currently be running in a window on your desktop.

In Magpie, click New Profile. Click the select a window dropdown. This will list applications which are currently running, so locate Tiberian Sun on the list (note select "Tiberian Sun" and not "[DDrawCompat] Tiberian Sun").


The new profile will appear on the left hand side, click it to view the settings. Change the Scaling mode to Integer Scale 2x (or the configuration you created in the previous step). For Tiberian Sun, you should be able to leave the other settings as their defaults.


Select the Tiberian Sun window and press Windows key + Shift + A. This will instruct Magpie to scale the application. Press the same combo again to disable the upscale, or alt+tab.

With the game now running full screen, take this opportunity to make sure that the game is running at your preferred source resolution. Click Options -> Display -> select 1280x720.

With these steps completed you should now have Tiberian Sun running at a usable resolution, which is being cleanly scaled up to your desktop resolution. It's time to Command and Conquer!

If you use an NVIDIA GPU and their overlay software, there is currently an incompatibility between that and DDrawCompat[github.com] which results in the game menus becoming unresponsive over time.

You can work around this by disabling the NVIDIA overlay before playing the game.

There is an updated version of DDrawCompat available here[github.com] which should resolve the issue, allowing you to use the overlay while playing the game. You would simply copy this .dll file into the games directory, overwriting the existing version. Hopefully a future release of DDrawCompat will include this fix, and EA will update the game to automatically use that version.

• Magpie must be running for it to be able to upscale the games window.
  
• If you don't want to use the button combo to activate the upscaling then you can configure the games profile to automatically upscale when the window is in the foreground (ie. whenever it is selected). Note that if you use this then sometimes the intro FMV will display as a black screen, you can alt-tab out and back in to fix this.
  
• If you use multiple monitors you may want to enable the 3D game mode option in the Magpie profile for the game. This will prevent the mouse escaping the upscaled window. Note that using this option seems to break the in-game mouse hover tooltip function (eg. showing the price of a unit when mousing over the right hand menu).
  
• If your target resolution is 1080p, you may struggle to find a source resolution which scales well to this. If your GPU drivers support it, you could create a custom resolution such as 960x540 to use as your source resolution, and then apply the Integer Scale 2x configuration to evenly scale up to your target of 1080p.
  
• I am not affiliated with Magpie, other applications which perform similar scaling are available however I have not used these. The steps to configure Tiberian Sun to run in windowed mode should be applicable to them too.