Minecraft Alpha-v1.2.6

This is based off of real Minecraft Alpha v1.2.6, the decompiled source code has been ported to TeaVM with as minimal changes as possible. Multiplayer has been removed because I am too lazy to rewrite it, do NOT ask for multiplayer to be added. Worlds and settings are saved to your browsers local storage using IndexedDB, the reason why the world size's are so large is because I had to leave them uncompressed, whenever I tried to compress them using CompressedStreamTools, TeaVM would get stuck on an infinite loop. A newly generated world may take up around 20 MBs.

Play the official release (No download required)

Download offline HTML file

Making a client

Gradle

After modifying files in src/main/java you can compile your changes to the javascript client by running gradlew generatejavascript, for linux run ./gradlew generatejavascript. This will then transpile the Java code into javascript files in /web/js.

Textures

The textures are compiled into resources.mc using Laxdude's EPK Compiler. The resources are located in /resources, after modifying the resources you can compile them using CompileEPK, and for Linux use ./CompileEPK.sh.

Offline Download

As of right now there is no system to compile an offline download, so you will have to manually copy and paste the javascript from /web/js/app.js into the HTML file, for the resources.mc just encode the file using Base64 and paste it into the assets div.

How to decompile older Minecraft versions

To decompile older Minecraft versions you can use RetroMCP!

RetroMCP is a rewrite of MCP that adds support for many different older versions of Minecraft that were never supported by MCP. To get started head over to the RetroMCP GitHub and download the latest release. Make sure you have Java 8 (or higher) installed in order to run and decompile Minecraft versions.

Code used within this project

• Modified version of Lax1dude's OpenGL Emulator from 0.30-WebGL
• Decompiled Minecraft Alpha v1.2.6 source code