In order to create a new custom version you just copy the json from the version that you want to modify and rename it and the "id" inside, then delete the entire "downloads" section which includes "client.jar", which is how I made the json for my own custom version (based on 1.6.4 but all versions work the same, all filenames/paths given are those for the 1.6.4 version of MCP so I'm assuming it hasn't changed since then. I also directly run the batch files by clicking on them, rather than using an IDE):
Before (only the parts around what was changed are shown):
"assets": "legacy", "downloads": {"client": {"sha1": "1703704407101cf72bd88e68579e3696ce733ecd", "size": 4745096, "url": "https://launcher.mojang.com/v1/objects/1703704407101cf72bd88e68579e3696ce733ecd/client.jar"}, "server": {"sha1": "050f93c1f3fe9e2052398f7bd6aca10c63d64a87", "size": 6146738, "url": "https://launcher.mojang.com/v1/objects/050f93c1f3fe9e2052398f7bd6aca10c63d64a87/server.jar"}, "windows_server": {"sha1": "30d3267c6b04422ef6349226ee539173f848574c", "size": 6542514, "url": "https://launcher.mojang.com/v1/objects/30d3267c6b04422ef6349226ee539173f848574c/windows_server.exe"}}, "id": "1.6.4", "libraries":
After:
"assets": "legacy", "id": "TMCWv4.5", "libraries":
The actual json can be seen here (TMCWv4.5.json, you can view it in the browser, note that it is all one line, as are the original jsons): https://www.dropbox.com/s/ioa73iyby4nl3sg/TMCWv4.5.zip?dl=0
Also, I'm not sure if you are trying to use the entire recompiled jar from MCP (in mcp\temp) but I took the files in mcp\reobf after running reobfuscate.bat, which only include modified and new classes (note that you cannot distribute a whole working jar as that is against the EULA, so that's another issue, plus this is not a complete jar, I looked in one and it doesn't have an assets folder, so textures and models would all be broken, if the game can even start without all of that data), and add them to an unmodified copy of the original jar, deleting the META-INF folder (essentially the same as installing mods prior to the advent of installers/before the 1.6 launcher, except for the changes to the json).
Otherwise, you need to modify the command line arguments that MCP uses to launch the game (CmdStartClt in mcp\conf\mcp.cfg), or modify the game to add a login method, both of which are detained here (I believe only the second method works in newer versions; in this case you should also do this before making any other changes and run updatemd5.bat so MCP ignores the changes you made when reobfuscating, since otherwise it will reobfuscate it and mess with the default login process):
https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/modification-development/2915357-tutorial-how-to-login-using-legit-minecraft
1
Yes, this is a farm based on that one by Ilmango but a bit smaller. Like I say, I'm not drowning zombies. I *am* getting nautilus shells so what is in their hands appears to be being harvested but no tridents so far. I was using a looting 3 sword when I got the trident I have but by my understanding, that only increases the odds a little. Ilmango's farm does have you kill the drowned yourself though.
I may try setting up a farm on a different server so I don't affect others with afk.