Bad Apple but it's a Windows virus

A high-performance (I've never seen anything like this run in realtime before) rendition of Bad Apple, using Windows windows as the video surface.

It's not actually a virus, but it is reminiscent of the viruses of old that were more of a nuisance than anything.

Video demonstration:

Why is it so performant?

• DeferWindowPos - even the most naive of projects can go from 1fps to 15fps by using this wonderful batched API instead of SetWindowPos.
• WS_EX_TOOLWINDOW to remove the taskbar entry
• SWP_NOREDRAW when moving/resizing windows
• Optimised code that only shows/hides/moves windows that need showing/hiding/moving
• Rust is blazing fast, don't you know?

Could it be faster?

I suspect that choosing which windows to move/resize, such that each is resized as little as possible, can increase performance - currently, the windows are just used from largest to smallest, which can result in some location jitter as they fit into different indexes.

Future work

All of these I have done already in small tests, but they're both difficult to make performant (copy dialogs are particularly slow), and difficult to arrange into a pleasing display.

• Spawning MessageBoxA windows and taking their handle (thus avoiding the need to replicate the layout of MessageBoxA for each version of Windows you run on)
• Spawning Vista file copy dialogs using IProgressDialog
• Arranging windows in rolling sine waves, circles, etc

All of these I have not tried yet, but would be great additions:

• Water physics using hundreds of scroll bars
• Basic hard-body physics between windows
• Error noises synced with the audio (could just pre-render...)
• Notification bubbles
• Windows in the taskbar to show text (if the user has large taskbar buttons enabled)
• A large variety of error messages to delight the user with

Building and such

Should be fine to just cargo build --release.

Look at bad apple.py for the pre-processing to take an input video and turn it into boxes.bin, a space-optimized representation of the window bounds for each frame. The script is jank, don't come complaining.