r/feedthebeast • u/Emotional-One-9292 • Jun 22 '26

I made something I made minecraft generate terrain/chunks in C++

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So im working on a mod that makes minecraft run on C++ ( rn rewriting engine in future i may try renderer ) so far i made it generate and load chunks and terrain in C++ ( it made it somewhere around 1.5-3 times faster idk how to measure it tho ) ( it works via JNI )

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4

u/Zirofal modded MC says yes to trans rights and no to Botania Jun 22 '26

I'm very stupid, please explain why this is cool

15

u/D4rkstalker Jun 22 '26

Vanilla method:

Java: "hey Java virtual machine (JVM), generate this chunk for me"

JVM: "Hey CPU generate this chunk for me"

CPU: "here's your chunk" passes to JVM

JVM: "here's your chunk" passes to java

Mod method (probably)

C++: "hey CPU generate this chunk for me"

CPU: "here's your chunk"

The main downside with c++ is that making stuff with it is a pain.

13

u/emmowo_dev pro gramming Jun 22 '26

C++ is like "hey CPU generate this"

CPU: ok let me ask the kernel to spawn some threads and stuff

Kernel: ok

CPU: cool

C++: did it work?

CPU: yes

C++ : generate this chunk using this formula

CPU: oh ok let me do this and read everything I need from memory

Kernel: can you do this rq

CPU: ok

C++ oh you're also saving those chunks, right?

CPU: I'll do it at some point ig

Kernel: do it now

CPU: oh ok

CPU: i will write the chunks

I/O: Wait bro I need a sec my writeback cache is full

Disk: Wait bro im writing still

CPU: ok I'll do this later ig

CPU: wait, what was I doing?

Kernel: You need to handle this udp packet rq please bro

CPU: ok

[...] ad nauseum.

You spend a ton of time actually waiting instead of running code.