Jump Cancel/zh

跳跃取消（Jump Cancel）是一种机制，通过取消玩家的初始跳跃速度，允许玩家在跳跃后保持在地面上.

这是步行辅助应用于跳跃运动的结果.

跳跃取消用于提高助跑的效率（通过将每次跳跃的持续时间减少到只有2 ticks）.

有两种方法可以取消跳跃：


 * 使用台阶、楼梯或其他一些可以触发跨步的方块 (0.42b < 高度 < 0.6b).
 * 用天花板 (1.8bc < 天花板 < 2.22bc).

步行辅助变体
该变体是有意设计的, 因为它是步行辅助机制应用于跳跃的逻辑扩展.

这种技术在速通社区中也被称为“楼梯加速”.

此变体仅在台阶高度差 Δ介于 0.42m 和 0.6m 之间时才有效.


 * 如果 Δ < 0.42m，玩家在可以检测到碰撞之前跳到台阶上方.
 * 如果 Δ > 0.60m，会存在碰撞，但高度太高，无法应用步行辅助机制.

走上台阶时，游戏会尝试通过以下方式正确移动玩家：


 * 1) 将 Y 速度设置为 0.
 * 2) 设置台阶上方的 Y 坐标.

在这个过程中，跳跃的垂直速度丢失，但水平速度保持不变. 这使玩家能在 2ticks 之后再次跳跃.

注意：可以使用台阶的角来取消跳跃而不移动到台阶上. 为此，碰撞必须是 X 朝向的. 例子.

天花板变体
. 这个变体是意外出现的，在1.14版本中和步行辅助一同修复了

此变体仅在天花板高度 Δ 在 1.8m 和 2.22m之间时有效.


 * 如果 Δ < 1.80m，天花板太低，玩家会卡在天花板里，游戏会认为是与墙发生了碰撞.
 * 如果 Δ > 2.22m，起跳的第一 tick 不会与天花板发生碰撞.

Ceiling jump-cancel is performed by jumping "into" a ceiling:


 * 1) The player must start on ground, with no ceiling directly above them.
 * 2) The player's next intended position must collide with the ceiling.

It is possible to chain multiple jump-cancels under a ceiling by repeatedly jumping in and out of the ceiling.

In that case, it's referred to as grinding, and is virtually equivalent to "1.8bc" momentum, minus the negligible cost of speed for micro-turning.

For example, a 1bm hh 5b is possible by using grinding:

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This technique requires extremely quick and precise mouse movement, but it's possible to use it in real time.

Version Differences:
Cancelling a jump under a ceiling was made possible in 1.8 when Mojang fixed a bug which prevented entities from walking through a gap.

However, it wasn't until version 1.8.1 that the ceiling variant became practical, as the player would often glitch through the floor. Indeed, in 1.8.0, The game would force the player to be set 2.4m under the ceiling (1.8m player height + 0.6m step height), even if a block was present. As of 1.8.1, the stepping method never goes below the player's position, so the player can no longer get glitched into the floor.

Before 1.8.1, grinding under a headhitter ceiling wasn't possible.