View source for Minecraft:Block offset

{{Partially conjecture}}
[[File:5x5 Grid of Poppies.png|thumb|A completely filled in 5 by 5 grid of [[poppies]], where each flower is subject to a block offset]]
Certain non-solid blocks, such as [[Minecraft:short grass]], [[Minecraft:pointed dripstone]], and some [[Minecraft:flower]]s do not have their textures or hitboxes centered on blocks they are placed on, and are instead staggered in a {{w|Pseudorandomness|pseudorandom}} manner. The offset of a block depends solely on its X and Z coordinates, and not the world seed. This means that, for example, a row of flowers at the same coordinates will always be staggered the same way between worlds, and this will not be changed by a player breaking or replacing them.

All blocks with an offset have their hitbox and/or texture translated in the X and Z axis. Some blocks such as [[Minecraft:short grass]] or the [[Minecraft:fern]] additionally have an offset in the Y axis for their textures only. The base X, Y, and Z offsets of a block are consistent between all blocks at a certain coordinate. However, some blocks (such as [[Minecraft:bamboo]]{{Only|bedrock}} or [[Minecraft:pointed dripstone]]{{Only|java}}) may use the base offset slightly differently than most blocks for block placement.

== List of blocks subject to offset ==
The following is a list of blocks subject to an offset in game. Most blocks have their hitbox offset to match their texture being offset, but some do not.
{| class="wikitable"
|+ Blocks subject to offset
|-
! Block !! Hitbox XZ offset || Texture XZ offset 
!Hitbox Y offset|| Texture Y offset
|-
| {{BlockLink|Short Grass}}<br>{{BlockLink|Fern}}<br>{{BlockLink|Short Dry Grass}}<br>{{BlockLink|Tall Dry Grass}} || {{tc|Yes}} || {{tc|Yes}} ||  {{tc|partial|''Bedrock Edition'' only}} ||  {{tc|Yes}}
|-
| {{BlockLink|Mangrove Propagule}}<br>{{BlockLink|Dandelion}}<br>{{BlockLink|Golden Dandelion}}<br>{{BlockLink|Torchflower}}<br>{{BlockLink|Poppy}}<br>{{BlockLink|Blue Orchid}}<br>{{BlockLink|Allium}}<br>{{BlockLink|Azure Bluet}}<br>{{BlockLink|Tulips}}<br>{{BlockLink|Oxeye Daisy}}<br>{{BlockLink|Cornflower}}<br>{{BlockLink|Wither Rose}}<br>{{BlockLink|Lily of the Valley}}<br>{{BlockLink|Bamboo Sapling}}<br>{{BlockLink|Bamboo}}<br>{{BlockLink|Pointed Dripstone}}|| {{tc|Yes}} || {{tc|Yes}} || {{tc|No}}|| {{tc|No}}
|-
| {{BlockLink|Sunflower}}<br>{{BlockLink|Lilac}}<br>{{BlockLink|Rose Bush}}<br>{{BlockLink|Peony}}<br>{{BlockLink|Tall Grass}}<br>{{BlockLink|Large Fern}}<br>{{BlockLink|Pitcher Plant}}<br>{{BlockLink|Warped Roots}}<br>{{BlockLink|Nether Sprouts}}<br>{{BlockLink|Crimson Roots}}<br>{{BlockLink|Hanging Roots}} || {{tc|partial|''Bedrock Edition'' only}} || {{tc|Yes}} || {{tc|No}}|| {{tc|No}}
|- 
| {{BlockLink|Coral Fans}}<br>{{BlockLink|Dead Coral Fans}} || {{tc|Partial| ''Bedrock Edition'' only}} || {{tc|Partial| ''Bedrock Edition'' only}} || {{tc|No}}|| {{tc|No}}
|-
| {{BlockLink|Coral}}<br>{{BlockLink|Dead Coral}} || {{tc|Partial|''Bedrock Edition'' only}} || {{tc|No}}<ref group="note">{{bug|MCPE-228149||Unlike the Coral fans, all Corals only have their hitbox randomly offcentered but not their block}}</ref> || {{tc|No}}|| {{tc|No}}
|-
| {{BlockLink|Tall Seagrass}} || {{tc|No}} || {{tc|Partial|''Java Edition'' only}} 
| {{tc|No}} || {{tc|No}}
|-
| {{BlockLink|Small Dripleaf}}||{{tc|No}} ||{{tc|Partial|''Java Edition'' only}}
| {{tc|No}} ||{{tc|Partial|''Java Edition'' only}}
|}

== Effects of block offset on textures and hitboxes ==
{{Expand section}}
In {{JE}}, X and Z offsets are added to the coordinates of the center of the block to determine the new center of the texture or hitbox. In {{BE}}, X and Z offsets are used differently depending on the block. On both versions, the Y offset is directly added to the Y coordinate of the block to determine what Y level a texture will start. A Y offset will always be negative or zero, meaning a block's texture or hitbox may be translated downwards but never upwards.

== Calculation of block offset ==
=== X and Z offset ===
The following algorithm is used to calculate X and Z offsets of blocks (except for [[Minecraft:pointed dripstone]] in ''Java Edition'', given a block's X and Z coordinates.<ref name="offsetAlgorithm">From {{Java classpath|net.minecraft.world.level.block.state.BlockBehaviour}}#offsetType({{Java classpath|net.minecraft.world.level.block.state.BlockBehaviour.OffsetType}})</ref> Note that {{w|Two's complement|two's compliment arithmetic}} while treating all integers as signed 64 bit numbers must be used for correct results.<ref group="note">This corresponds to standard arithmetic operations involving the <code>long</code> datatype in {{wp|Java}}.</ref>
<syntaxhighlight lang="c">
temp1 = (0x2FC20F * x) XOR (0x6EBFFF5 * z)
temp2 = (0x285B825 * temp1 * temp1) + (0x000B * temp1)
x_offset = ((temp2 AND 0x00F0000) / 15.0 - 0.5) * 0.5
z_offset = ((temp2 AND 0xF000000) / 15.0 - 0.5) * 0.5
</syntaxhighlight>

On ''Java Edition'', the X and Z offsets of pointed dripstone are given by calculating <code>x_offset</code> and <code>z_offset</code> above, and {{w|Clamp (function)|clamping}} the values between -0.125 and 0.125. All other blocks have their X and Z offsets clamped between -0.25 and 0.25.<ref group="note">The <code>y_offset</code> however is not clamped</ref>

=== Y offset ===
The Y offset depends solely on the X and Z coordinates of a block and the block type. For all blocks with a Y offset besides [[Minecraft:small dripleaf]], the Y offset is given by (using the variable <code>temp2</code> from above):<ref name="offsetAlgorithm"/>
<syntaxhighlight lang="c">
y_offset = ((temp2 AND 0x0F00000) / 15.0 - 1.0) * 0.2
</syntaxhighlight>
On ''Java Edition'', the Y offset for small dripleaf is half as much as the Y offset for other blocks at the same coordinates.

== Notes ==
{{notelist}}