Open your eyes
Ok, so this lesson doesn’t do anything with the MCP, but it’s great that you’ve set it up so you don’t waste time in later lessons. Setting up after you started this set of lessons will be frustrating, especially since you don’t want to go back to the beginning to do everything all over again.
Great, you’ve made it this far. In this lessons we will learn as much as there is to know about the minecraft.jar file. That’s where your world exists, Minecraft world, that is. The minecraft.jar file is simply a zipped up file with a bunch of other files and folders that contain information about how to build your minecraft world. It’s like the DNA and the RNA used to build an entire living being. Screw up the code, and you get a nasty mutant.
First thing in this lesson is to extract the contents of our minecraft.jar file. You can simply do this from your game folder. This assumes that you have done no other mods to the code. Basically, you want to modify the last good working copy of the minecraft.jar file. If you’ve modified your files around, and have fiddled around in your working environment you set up already, for this lesson, you need the last modified copy of your minecraft.jar file that works.
Before you extract this file, it’s ALWAYS a good idea to back up your original files, no matter what. In this case go ahead and copy the minecraft.jar file to something that makes sense, like minecraft.jar.bkp for backup. It’s ok if you change the extension. The data inside won’t be damaged. You simply painted its shell a different color.
Now, use a program like 7-Zip, or WinRAR. For this lesson, I will use WinRAR.
Extract the files to “minecraft” folder.
And the folder…
In this folder, look for a file called “terrain.png”.
Here’s the kicker. You need a software program that can view, edit, and save .PNG image files. You can use open source software such as Paint.Net or GIMP. You can find them here respectively:
First step, ALWAYS backup your original files. You will need to get your “terrain.png” file backed up. Make a copy and put it in a safe place. I made a folder in “My Documents\My Dropbox” that deals with keeping any file backed up and as safe as it could be.
This file may look different depending on the version of your game and other modifications.
Now, you’re ready to make changes. Open your terrain file with your preferred image editor, and while staying within the lines, modify your “dirt” block. Why the “dirt” block? It’s the most commonly seen when you start out.
Here’s another closeup look of the modification.
Now, to re-compile the minecraft.jar file. All you have to do is use your zipping program to create a compressed file, but with a .jar extension. You can simply just compile the file contents and then rename the file.
* Keep in mind to compile the CONTENTS of the minecraft folder, NOT the folder itself.
Here’s what I did: I selected all of the files in the minecraft folder, right clicked, and selected to add files to a compressed file.
When compressing, I chose ZIP format, then renamed the file extension to .jar.
When all said and done, move the newly created minecraft.jar file into your minecraft game folder. Make sure you backup your original file, as you don’t want to lose a working copy of your game.
If you did everything right, when you play your game, you should see your changes.
In this lesson, you learned how to modify your terrain texture file to change the look of your world. You’ve also learned a little about the minecraft.jar file and how it’s compressed and structured.