mojira.dev
MC-128926

Wrong observer timings

Summary

Two observers facing into each other form a clock, as intended. However, in 1.13 the resulting clock has the wrong timings.

Expected behavior

In 1.11 and 1.12, pushing/pulling an observer (using a piston) in front of another observer creates a 4 gametick clock. The observers are out of phase: one is on for 2 gameticks while the other off for 2 gameticks, and then they switch.

The bug

In the 1.13 snapshots, the same clock has a 6 gametick cycle. Each observer is on for 2 gameticks then off for 4 gameticks.

Why this should be fixed

This behavior is wildly used to create fast clocks. A 4 gametick clock is useful as it matches the speed of droppers. By contrast, 6 gametick clocks have very few practical uses.

Related issues

Attachments

Comments

migrated
[media][media]
migrated

Another reason to fix: This change implies something has changed with how observers react to change.
The reason why pushing with a piston created a 4gt clock is that when the piston pushes, it places the piston extension (aka block36) directly in front of the observer, which the observer detects. This creates the offset of 2gt between the observer pair, making them trigger every 4gt by detecting each other's change.

MukiTanuki

Can confirm for 18w20a.

This is especially troubling as it breaks a great deal of redstone contraptions.

Here is setup testing timing outputs with command blocks:

[media]
MukiTanuki

present in 18w20b

MukiTanuki

present in 18w20c

MukiTanuki

present in 18w21a

MukiTanuki

present in 18w21b

MukiTanuki

present in 18w22a

MukiTanuki

present in 18w22b

MukiTanuki

present in 18w22c

LuxiKeks

Affects 1.13-pre1...

MukiTanuki

present in 1.13-pre2

Irbis

1.13pre3 affected.

LuxiKeks

This seems to be fixed in pre4, can someone confirm?

 

MukiTanuki
[media]

Can confirm that it at least appears to be fixed.

migrated

Affects 1.14.1 pre2

migrated

(Unassigned)

Community Consensus

observer

Minecraft 18w16a, Minecraft 18w20a, Minecraft 18w20b, Minecraft 18w20c, Minecraft 18w21a, ..., Minecraft 18w22b, Minecraft 18w22c, Minecraft 1.13-pre1, Minecraft 1.13-pre2, Minecraft 1.13-pre3

Minecraft 1.13-pre4

Retrieved