Minecraft pack.png tutorial

Original Reddit post: https://www.reddit.com/r/MinecraftAtHome/comments/iocx6f/packpng_seed_was_found_explanation_tutorial_and/
SalC1's video explanation: https://www.youtube.com/watch?v=ea6py9q46QU
Methodology: https://bit.ly/packpng-details
Credits: https://mcatho.me/packpngcredits

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Here's all the parameters to replicate the pack.png image yourself:
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Version: Alpha 1.2.2a [JAVA]
Seed: 3257840388504953787
Player X: 49.16~
Player Y: 64 (65.62 eye position)
Player Z: 0.72~
(This is the position of the player in alpha, not the camera itself. The camera is moved -0.1 backwards, i.e. opposite to the look direction, so if you're using anything else than alpha/beta MC, you have to compensate for that yourself.)
Camera yaw: -119.23 (horizontal rotation angle)
Camera pitch: -8.297 (vertical rotation angle)
FOV: 70 (Normal) (that's all that was possible in Alpha)
In-game time: 34 seconds (for the clouds to match. must be after a fresh game launch, and in versions before b1.8)
Window resolution: 1600x1116
Crop position: 622;284 (top-left corner, screen starts at 0;0)
Crop size: 512x512
Downscaled to: 128x128 (factor of 4, using SuperSampling a.k.a. Box scaling)

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Here's a tutorial on how to load this seed in the Alpha version:
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1) You need to use the correct Minecraft Java version Alpha 1.2.2 otherwise it won't work. Don't forget to enable historical versions in the launcher, otherwise it will not show up. "Release 1.2.2" IS NOT THE CORRECT VERSION! It must be alpha.
2) This version doesn't support manually entering seeds. To be able to use the pack.png seed, a work-around is needed:
 - Load the correct Minecraft version and create a new world (for example, choose "World1"). After it loads, save and close the game.
 - Go into your Minecraft saves folder and open the folder of the world you created (for example "World1").
 - Make sure you're in the correct folder (you should be seeing folders with random numbers and letters).
 - Delete everything inside this folder except "level.dat". Only this one file should stay there.
 - Download NBTExplorer: https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-tools/1262665-nbtexplorer-nbt-editor-for-windows-and-mac
 - Use NBTExplorer to open the "level.dat" file and change the "RandomSeed" value to the pack.png seed.
 - It's also a good idea to modify the player position while you're here. Expand the "Player" section and modify the position (and rotation too if you want) values to the ones described above.
 - After you've done that, click the save button and close the program.
3) Now open Minecraft again and load this world. You should now be standing nearby the pack.png hill, congratulations!

MODERN VERSIONS:
If you want to load this world in a modern version afterwards, then after you've generated as many chunks in Alpha as you want, load it in Beta 1.7.3 so it's converted to a newer format, and then you can load it in any newer version you want.

If you're still having problems, you can ask me on Twitter or Discord, but please READ EVERYTHING carefully first before you ask!