The ddnet antiping is quite complex. For now prediction for other players, projectiles and rocket jumps would be okay I think. Projectiles and other players shouldn't be that hard. Rocket jumps are a bit more work... You need to simulate the rocket before the server knows about it
You can just share all the physics related code between server and client. For the local character they already use the same code. You could also do this for projectiles but then you can't change physics after a release without breaking the prediction.
16:25
Gamecore should be migrated to lua/wasm/whatever so the server can send its code to the client
There is some old ddnet version with websockets. There are some tools to compile c/c++ apps to JavaScript/webassembly but you definitely need to change some things.
17:39
As I said... Network needs to use websockets and the rendering will be a problem
17:39
Tw uses threaded rendering + opengl 1.2
17:40
You would need a new renderer to make it work in the browser
I realized the game looks pretty pixalated so i went to the graphics settings and i wonderd why the resoltion is so low. Then I tried to increase it. But after restart the same option was selected ...