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
• BitDepthFix for versions before Beta 1.8
• 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
  • Skins don't work in Java versions before 8u181, due to the requrement of TLS 1.2 support
• 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 automatically download minecraft_server.jar for snapshots: 12w18a, 12w19a, 12w21a
• The wrapper is fully compatible with Java 5+ if the game is vanilla
  • The wrapper also fixes Beta 1.3, Pre-classic and Classic compatibility with Java 5
• Built-in Modloader Fix

How to use

There will be an installer eventually.
For now, here is an in-depth guide for those who will be using the wrapper

• If you are using MultiMC, follow this guide.
  
• If you are using Official Launcher (or any other launcher which follows the same versions folder structure), use BetterJSONs and rename the JSONs if they are conflicting with any vanilla JSONs

Setting up manually

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
• 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 - pre-c0.0.19a / classic / pre-b1.9-pre4 / pre-1.8 / default - convert the skin to one of these specified formats
  • pre-c0.0.19a - flatten all skin layers, flip bottom textures, mirror entire skin and crop to 64x32
  • 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
• applet - Makes the game think you're running an applet (Which removes quit button for example)
• oneSixFlag - Toggles notice about the release of 1.6 in 1.5.2
• + any Minecraft launch arguments or applet parameters