Jumping/ja

Jumping is an essential mechanic that is quite self-explanatory.

発動
ジャンプするには、その前のtickで地面に立っている必要がある. ブロック縁からでも1tick走って（例:ずらし）ジャンプできるのはこのためである.

ジャンプキーを押し続けていると、10tick（0.5秒）ごとに1回ジャンプできる.


 * 各ジャンプの高さが0.75b以上の場合、ジャンプキーを押し続けるのは最適ではない（結果: ブロックを積み上げる時は押し直しの方が速い）.
 * Releasing jump resets the cooldown, making the player able to jump again on the next tick.

When a jump is initiated, the player's vertical speed is set to 0.42. On every following tick, it is decreased by 0.08 (gravity), then multiplied by 0.98 (drag).

Jumping in water or lava makes the player move upward.
 * When the player hits a ceiling, their vertical speed is set to 0 and they immediately start falling.
 * When the player hits the ground, their vertical speed is set to 0 and the  flag is set as true.

ジャンプの高さ
1.8以前はジャンプの最高点は1.249b. 1.9で約0.003b上昇し、1.252bの高さまでジャンプできるようになった.

平らな地面では、1ジャンプの滞空時間は12tick（0.6秒）.

速度
When combined with Sprinting, jumping adds 0.2 units of acceleration towards the player's facing.

In air, the player accelerates less quickly (only 20% of the base acceleration value), but conserves more speed (91% every tick, instead of 54.6%).

Therefore, sprint-jumping is a very efficient way to build and conserve speed.

ソースコード
The following snippets of code deal with how jump is activated.