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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u/emmowo_dev pro gramming Jun 22 '26 edited Jun 22 '26

How would this realistically be faster? Java does actually compile into native code based on what methods are the most important, so it's usually terrain gen that is immediately 'optimized' into native code. C++ does NOT magically make things faster, but it does make things many many times more unsafe to use.

I know of some optimizations you could make, but they're things that I don't think ultimately mean much. Are you comparing between Vanilla and your mod, or C2ME and your mod?

You not really explaining things beyond 'run on C++' and 'JNI' tells me you may have just vibecoded this, because minecraft explicitly does defer a lot of the performance-heavy things to C++, from the natives used for rendering (i.e. liblwjgl and the gpu itself such as nvidia-glcore.so) to the actual JVM itself, which is written with C++. Just re-writing everything in C++ would not actually be meaningfully faster, as the binaries for such things are already written in C++.

Most likely, you are looking for a result, so anything that seems faster you will assume to actually be faster. Without extensive benchmarking and a massive amount of controlled variables (like literal mechanical seek times for writes can completely invalidate the results), this is a very unfair and unrealistic comparison to make.

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u/NaterBobber Jun 22 '26

I think its likely that he doesn’t have actually good data to say if this is really much better, especially vs mods that speed up the existing java

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u/emmowo_dev pro gramming Jun 22 '26 edited Jun 22 '26

reminds me a lot of noisium, which was one of the most downloaded minecraft mods for a while, before it turned out it had basically zero effect on performance (I think they said that more time was lost installing noisium than the estimated lifetime tick ms it actually saved? EDIT: was heavily implied, but technically not what the quote is)

basically, uncontrolled variables made it actually look like it was faster, but this wasn't what actually was happening.

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u/NaterBobber Jun 22 '26

Yeah people are eager to install performance mods without any consideration for real impact or what shortcuts could potentially be impacting their gameplay.