LaunchWrapper/README.md

LaunchWrapper

LaunchWrapper is a wrapper for legacy Minecraft which provides fixes for certain game features and also improves compatibility with launchers.

LaunchWrapper is bundled in BetterJSONs which are meant for official Minecraft Launcher.

Features

• Strips game window from Java AWT (Abstract Window Toolkit) and lets the game use internal LWJGL frame
• Allows changing assets directory in 1.6 snapshots (the game didn't have a parameter to do that yet)
• Allows changing game directory in versions before 1.6
• Replaces mouse input code with LWJGL calls
• Fixes TimSort crash when using java 8+
• Adds ability to customize built-in LWJGL frame
  • Changing display title
  • Setting icon
• Proxies all requests from old skin servers to the current skin API and converts skins to required format
• Uses Betacraft proxy to download sounds for versions before 1.6
• Adds ability to launch classic and pre-classic at custom resolution and fullscreen
• Makes save slots in classic and indev functional and saves to .minecraft/levels directory
• A launcher for isometric level viewer (IsomPreviewApplet)
• A VSync toggle (Used to prevent extreme framerate in early versions which causes coil whine)
• Does not depend on any hard-coded obfuscated names and is mostly compatible with every Minecraft version
  • This also includes modded versions
• A parameter to download minecraft_server.jar for snapshots which require it: 12w18a, 12w19a, 12w21a
• The wrapper is fully compatible with java 5+ if the game is vanilla

How to use

This is a more in-depth guide for people experienced in Java

Make sure all minecraft and wrapper libraries are on classpath
Use java -cp <classpath> org.mcphackers.launchwrapper.Launch <arguments> to launch the game

Arguments are formatted the same way as in Mojang launch wrapper.
For example: --username DemoUser --width 1280 --height 720 --title "Minecraft Demo" --demo

Arguments may be as follows:

• awtFrame - disable LWJGL frame patch and use AWT (Does not work at that moment)
• isom - Launch IsomPreviewApplet
• forceVsync - Launch the game with VSync enabled
• forceResizable - Early Indev and Classic don't properly update viewport, so the wrapper disables frame resizing. To enable it anyway use this argument
• skinProxy - classic / pre-b1.9-pre4 / pre-1.8 / default - convert the skin to one of these specified formats
  • classic - flatten all skin layers, flip bottom textures and crop to 64x32
  • pre-b1.9-pre4 - flip bottom textures and crop to 64x32
  • pre-1.8 - crop to 64x32
  • default - do nothing with requested skin
• resourcesProxyPort - Betacraft proxy port for sound resources
• serverSHA1 - Compare minecraft_server.jar in .minecraft/server against this hash
• serverURL - URL to download the server from if the hash is mismatched or the jar is missing
• icon - List of paths of icon PNGs separated by ;
• title - The display title
• oneSixFlag - Toggles notice about the release of 1.6 in 1.5.2
• + any Minecraft launch arguments or applet parameters