[MC-213779] FPS drops when looking up in a tall world (4064 blocks)

The bug

If you generate a tall world using custom world files, looking up(or down when far away from min_y) decreases fps by a very high amount without there being a lot to render

To reproduce

Load the custom world in the attachments
Look up
→ ❌ FPS drops dramatically

In 21w06a the total world height got increased to 384 by default, this issue now also occurs(less extreme, the world height is still lower than my custom world) by default in new worlds

Linked issues

is duplicated by 2

MC-210916 Significant FPS drop when being high above the world and looking down Resolved

MC-223116 shaking camera while looking up from bottom of world or down from top of world causes big FPS drop when vsync is on while playing in windowed mode Resolved

Attachments

Minecraft 21w05a - 2021-02-03 19-23-38.mp4

worldgen_settings_export.json

Comments 4

Irbis 2021-07-09T14:20:05Z

Considering that world height is 256 blocks and will be increased to 384, chunk rendering algorithm might need update that limits chunks and subchunks being rendered not only horizontally, but also vertically. 384 meters is similar distance to 24 chunks that need to render. Since default rendering distance is set to 12 or so, most of far area will be rendered as gray matter hidden by fog anyway. Solution for this would be limiting rendering to sphare of render distance instead of full world-height cube. Considering it needs to render only area in front, we can limit sphare to cone gaining quite good performance boost.

BBLZ 2021-07-10T06:23:46Z

I just noticed there are affected versions attached that don't even support datapacks increasing world height. Isnt this bug only noticeable in worlds with increased height?

[Mod] violine1101 2021-07-10T07:16:24Z

The older versions were transferred from MC-210916, see that ticket for details.

ampolive 2021-07-14T00:53:44Z

Can confirm in 1.17.1. This actually happens in regular worlds as well. For example, while looking down in the bottom of the nether, I get about 98 FPS, which promptly drops to about 52 when I look up.