trigger we simply check the

當碰撞體變成觸發器後就不再有碰撞行為 必須用程式來偵測判斷

'Is Trigger' checkbox on the component

如同一般的碰撞體

settings in the inspector.

當其他碰撞體進入觸發器時 會呼叫觸發事件

When a collider is a trigger things will

在這個範例裡我們設定方形碰撞體為觸發器 並放一個會掉落的球體物件

no longer bump into it. Instead they will

這個球體物件會掉進觸發器內 然後向前滾動最後離開

pass through it and this can be detected

來看看觸發器上的程式腳本

via code.

有觸發進入(OnTriggerEnter)

Similar to normal colliders,

並寫入訊息到控制台

events are called when other colliders

以及觸發持續(OnTriggerStay)

are overlapping with the trigger collider.

和觸發結束(OnTriggerExit)

In this example we have a box collider

如果我們將遊戲暫停 並單步執行每一幀

with Is Trigger checked

可以看到物件進入觸發器時 控制台顯示物件進入的訊息

and a falling 'prop samoflange' ball object.

持續停留的幀數和最後離開的訊息

This object enters the trigger,

如同碰撞體觸發的規則一樣 兩個物件其中一個必須有剛體

stays as it rolls forward and then exits.

設定觸發器的標準做法 是將觸發器設定為靜態物件

To check these events we attach a script

這樣它們就不會被物理引擎所影響

to the trigger, which is registering

所以通常是如同剛剛的範例 用一個有剛體的物件穿過它

OnTriggerEnter and logging to the console

我們讓有剛體的物件穿過觸發範圍 然後進行觸發事件檢查

and likewise OnTriggerStay

因此用來作為觸發器的碰撞體 也可以稱作觸發範圍(Trigger Zone)

and OnTriggerExit.

如此一來你就可以由程式來進行觸發判斷 而不需要由物件產生實際的物理碰撞

So if we pause the game

舉例來說, 這是一個飄浮墊

and step through one frame at a time,

我們可以讓球體物件往上增加一個力道(Force) 讓停留在觸發範圍內的球有飄浮的效果

looking at the console will show that the

我們可以呼叫觸發範圍內的物件

object enters the trigger

因為在觸發範圍裡的物件 會被存在一個名為other碰撞體類別

stays for a number of frames

然後我們可以呼叫它的剛體 並往上增加一個力道

and eventually exits the trigger.

Vector3.up是世界座標往上的簡寫

In the same way as standard collisions,

然後乘上一個值，並將結果存成一個變數

one of the two objects must have a rigidbody.

最後設定力道的模式函式就完成了

It's standard practice to make sure that your trigger

現在我們將球移動到飄浮墊上

colliders are static objects,

為了避免它亂跑我們凍結X和Z軸移動

meaning they will not be moved by the

只有Y軸允許被改變 因此它就可以產生漂浮的效果

physics engine. So usually you will make

接下來播放遊戲 可以看到球停留在漂浮的範圍內

a trigger and then pass a rigidbody

而球體就可以在沒有任何物理運算下 形成了漂浮的效果

through it. This example is no different.

We're passing our rigidbody object

through the trigger zone and detecting

when something enters that trigger.

So the intention with the trigger collider,

also known as a trigger zone,

is that you can call code without the

objects in your game physically colliding.

So for example, with our hoverpad,

we can add a force to our samoflange ball

to give the effect of it hovering

so long as it stays within the trigger zone.

For example, we could address the object

that's currently staying within the trigger

because the object that's staying

is saved in a variable called 'other'

of type Collider. We could then address

the rigidbody and add a force

in the direction of Vector3.up,

a shortcut for 'up' in world coordinates.

We could then multiply by a number

which we'll save as a variable.

And we'll finish out the AddForce

by choosing acceleration as the mode.

Now we'll move our object over the hoverpad

and we'll use Freeze Position to keep it

in the same place in X and Z.

Allowing the force of Y to create

the hovering effect.

And now if I press play, as you can see

as long as it stays within that area

it creates the effect of hovering without

having to interact without any part

of the geometry.