A modern Fallout 1 patch for Windows 10

TL;DR: A patch to bring Fallout 1 into the modern day with Game Bar support, proper mouse ballistics, and borderless fullscreen etc.

I tried replaying Fallout 1 recently and the experience both from the original disk or the Steam / GoG versions was very subpar. The first thing that happens on launch is a desktop resolution switch, messing up my desktop and all its windows. Alt-tabbing doesn't work, notifications are hit and miss, and exiting the game brings my computer to a crawl for 30 seconds or so while the resolution reverts back and some apps like *ahem* Windows Explorer don't survive the mode switch and crash, losing all my windows.

I thought that there has _got_ to be some way to do this better, and after being knee-deep in old DirectX SDKs I came up with a solution: a DLL that provides a virtualized, 90s era PC to the game while actually using D3D12 to do all the work. The game thinks it has a 640×480 256 color display etc, but in reality its rendering is captured and presented via DXGI and D3D12 for a modern borderless experience that you can alt+tab from, use with Game Bar, get all your notifications, etc. – sometimes I even put Fallout on a separate desktop and use four-finger swipes on my laptop's trackpad to game a little, then go back to email / work, and keep doing this whenever I have an idle 5 or 10 minutes.

One thing did annoy me though, and it was that the cursor in Fallout behaves "weird". I'm familiar with how my mouse moves since I use it all day on the desktop, but Fallout has a very primitive pointer mapping with no acceleration or ballistics which might be a good idea for a shooter but for a point and click game it isn't The Right Thing – so I intercepted DirectInput and manipulated the values sent to the game so that the mouse moves in-game just as it would out-of-game, same acceleration curve and everything. This is subtle but it makes for a huge difference – zero mental friction when I go into and out of the game. YMMV, but it's my favorite feature in all this.

Keep in mind that this is a very early build and I only tried it on two machines. There are some known issues:

– Multiple monitors might not work – I'm away from my desk so I can't test this

– Mouse cursor sometimes goes out of sync – move the mouse to a screen corner then back to fix. Will be patched soon

– Does not work on Intel cards, they have a driver bug and I've tried to inform them with no luck whatsoever

To try this patch, get this modified DirectDraw DLL and place it right next to `falloutw.exe`, then launch the game. This does not currently work with the high-resolution patch. Let me know if you have any issues and I'll do my best to fix them.