The extent property of feature rule and scatter feature grid distribution types generates features offset from the given range.

Partner Rank: 3

Partner Team Reporting: Mush Co

Verification Builds: From at least Minecraft Version 1.16.200 to the latest Preview, Minecraft Preview Version 1.20.20.22

Regression Builds: N/A (always observed to be broken)

Summary:

The extent property of feature rule and scatter feature grid distribution types generates features offset from the given range.

Affects currently Live Content: No

Impact:

Extended development time and complexity. Every instance of this bug requires an additional scatter feature definition as a workaround. These insertions also decrease performance. This bug is also notably inconsistent across distribution types; this inconsistency makes feature placement tweaking more time-consuming.

Repro Steps:

1. Open the attached world: Feature Extent Bug Demonstration World.mcworld
2. Enter the imported world.
3. Teleport to the build height limit: run the command /tp 0 320 0.
4. Observe the obsidian platform not conforming to the specified extent in Observed Results below.
5. Fall to the ground level. Glowstone columns should be present at most ground-level altitudes.
6. Observe the surface glowstone columns not conforming to the specified extent in Observed Results below.
7. Enter spectator mode: run the command /gamemode spectator.
8. Turn on night vision: run the command /effect @s night_vision 1000 0 true.
9. Teleport underground: run the command /tp 0 -16 0.
10. Observe the underground glass columns not conforming to the specified extent in Observed Results below. Note that what appear to be air columns are actually glass.

Observed Results:

• The 4 × 4 obsidian platform generates from (0, 319, 0) to (3, 319, 3). Note that all other platforms are also offset in each chunk.
• The 128-tall surface glowstone columns generate from y 0 to y 127.
• The 64-tall underground glass columns generate from y -31 to y 0.

Expected Results:

• The 4 × 4 obsidian platform generates from (10, 319, 10) to (13, 319, 13). All other obsidian platforms generate +10 in both x and z within each chunk.
• The 128-tall surface glowstone columns generate from y 128 to y 255.
• The 64-tall underground glass columns generate from y -64 to y -33.

Screenshots/Videos attached:

Shows the 4 × 4 obsidian platform generating in the incorrect position. The current player position and opposite-corner debug block position are shown at (0, 319, 0) and (3, 319, 3) respectively.

 

Shows the 128-tall glowstone columns generating in the incorrect position. The top of the columns are shown to be incorrectly positioned at ~y 127.

 

Shows the 64-tall glass columns generating in the incorrect position. Note that what appear to be air columns in this image are actually glass. The bottom of the columns are shown to be incorrectly positioned at ~y -31.

Notes:

• The extent bug only affects the grid distribution types: grid and fixed_grid. Other distribution types correctly generate features in the given range.
• The bug is present in both feature rules and scatter features.
• All format versions from the earliest (1.12 for feature rules and 1.13 for scatter features) to current are affected.
• Both positive and negative ranges that don't intersect 0 are affected.
• Both interpreted Molang strings and direct JSON numbers are affected.
• Distributions for all of x, y, and z are affected.
• The remapping is such that the range will always minimally include 0. For example, an extent of [-64, -33] will be offset +33 to include 0, presenting in-game as [-31, 0]. A range of [128, 255] will be presented as [0, 127].
• The behavior pack is included separately for testing in other worlds/seeds.