Minecraft Java Edition – Best Y Level to Find Ancient Debris

Unfortunately since the level generation algorithm has changed, using the same seed as before will generate a completely different map in its place. There are new biomes, their sizes are different, and the land features are different too. Since my friend and I have structures we would like to save, we're faced with the same problem you are.

It is nearly impossible to get a world that will match your existing one, and if your structures are like ours, it depends heavily on the land it was built on. Maybe you can paste in a whole island at once or something, but even then the biomes won't match (if you care about appropriate weather in the area you built it).

This is admittedly an opinion here, but my advice would be to start fresh; turn a new page. The Adventure Update is for exploring! Go have fun with the new features, and save your maps elsewhere for nostalgia. The update supports old maps, so you can always go back to see them and build upon them.

The answer provided by Flaunting is correct, but in case anyone is interested why it might be more efficient, here is an explanation.

In immediate mode (I think this is the default case in minecraft) when you want to render say a square:

You would issue the following commands each frame (in pseudo code)

begin drawing
draw line from (0,0) to (1,0)
draw line from (1,0) to (1,1)
draw line from (1,1) to (0,1)
draw line from (0,1) to (0,0)
end drawing

For one square, this is not a lot, but there could be millions of vertices in a scene, and they may have more attributes (colour, normal etc.). This is a lot of data to send to the GPU each frame.

Using VBOS, you would load all of the vertex data into GPU memory at the start. Pseudo code might look like this:

create VBO
load (0,0) into VBO
load (1,0) into VBO
load (1,1) into VBO
load (0,1) into VBO
load (0,0) into VBO

The OpenGL code will give you back a 'name' for this VBO (a non-zero unsigned integer iirc). You can then reference this when you want to draw the square. So each frame, you only need to issue one draw command:

draw vertices in VBO

You may have to set up the drawing state so that it uses pairs of vertices for lines, but for each additional VBO, you only require one extra draw call. In fact, for static level geometry (probably not applicable in the case of minecraft) you can combine all of these vertices into one massive VBO, if you have enough GPU memory.

I'm surprised that the speed-up is only 5-10%. This is probably because of the dynamic level geometry.