Eaglercraft - 1.12 Wasm Gc Repack

Alex recompiled the 1.12 client using a custom TeaVM fork targeting Wasm GC. Instead of outputting JavaScript heap management, every object allocation, every new BlockPos() , every HashMap of entities — all became Wasm GC structs and arrays, traced and collected by the browser’s optimized garbage collector.

The first test was a superflat world with 64 villagers. On the JS backend, frame rate dropped to 15 FPS with major GC spikes every 5 seconds. On Wasm GC? A steady 45 FPS. No visible hitches. The collector ran concurrently, reclaiming entire chunks of blocks and entity pathfinding data without stopping the world — in both senses. eaglercraft 1.12 wasm gc

Because Wasm GC is a relatively new web standard, Alex recompiled the 1

After weeks of patching, a breakthrough: the first stable 1.12.2 survival world running entirely in Wasm GC mode. Chunk loading was snappy. Entity AI computed faster. And the memory footprint? Down 30% — because Wasm GC structs are far more compact than JS objects. On the JS backend, frame rate dropped to

The headline feature of the new Eaglercraft builds is the use of . To understand why this is important, we have to look at how browser Minecraft used to work.

But it wasn't magic. Wasm GC lacked finalizers, so native resources (like WebGL textures) still needed manual cleanup. The class hierarchy of Minecraft — TileEntity subclasses, IRecipe types — all required precise casting support. And the biggest hurdle: reflection. Minecraft 1.12’s ObfuscationReflectionHelper and dynamic proxies broke. Alex had to write a custom transformation pass at compile time to replace reflective calls with direct Wasm GC casts.

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