Post

@breakintoprogram.co.uk

Here are some words what I wrote.

breakintoprogram.co.ukI Accidentally Wrote an Emulator (Part 7) - L Break Into Program, 0:1In the previous articles I discussed: It was time to embark on a side mission. Emscripten Emscripten is a toolchain that will compile native C and C++ to WebAssembly (webasm). WebAssembly is a low-lev...

2/9/26, 10:59 am8 reposts36 likes

L Break Into Program

@breakintoprogram.co.uk

2 Sept

Note for Windows PC users - apologies for the shift keys not working properly. I've mapped left shift to CAPS SHIFT and right shift to SYMBOL SHIFT. For some reason a KEYUP event consistently goes missing when you hold both shift keys then release one or both. Works fine on Linux and Mac.

L Break Into Program

@breakintoprogram.co.uk

2 Sept

Word on the street is that this is some weird legacy Microsoft Windows thing, which I've confirmed with a test Windows app I wrote. I can't find any official documentation on this though other than a mention in this thread. github.com/libsdl-org/S...

L Break Into Program

@breakintoprogram.co.uk

2 Sept

I'll be updating the emulator shortly so that it uses another key sequence for Windows users.

L Break Into Program

@breakintoprogram.co.uk

3 Sept

It's probably telling that the other online emulators I've tried (jsspeccy, qaop) use left shift for CAPS SHIFT and alt-gr for SYMBOL SHIFT. Might as well fall in line with them.

Gaz

@gazchap.com

2 Sept

Something to do with StickyKeys?

L Break Into Program

@breakintoprogram.co.uk

2 Sept

Dunno what the reason is.

Tom Keresztes

@tkeresztes.bsky.social

3 Sept

Are you using VK_SHIFT ?

L Break Into Program

@breakintoprogram.co.uk

3 Sept

No, In my distilled Windows test example I'm using VK_LSHIFT and VK_RSHIFT in the messages WM_KEYUP/DOWN. In the emulator I'm using SDLK_LSHIFT/RSHIFT.

Tom Keresztes

@tkeresztes.bsky.social

3 Sept

windows treats modifier state as unified , e.g. here both shift keys, but will only send one keyup when the last is released. you can call getkeystate for vk_lshit and rshift on every shift event (keyup, down, syskeyup, etc) like bool ls = GetKeyState(VK_LSHIFT) & 0x8000) != 0 . or raw input.