# Events

Use Cases: 

* Show HUD at game start
* "Auto unlock" quests upon entry
* Track total player count in an Experience
* Send messages to specific broadcast targets

{% hint style="warning" %}
Set **Broadcast Type** to *All* or *Rules* to send messages from objects to the Rules System.
{% endhint %}

## On Player Join

{% tabs %}
{% tab title="About" %}

### On Player Join

This rule sends a message each time a new player joins an Experience.

<figure><img src="https://331512196-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F83PS3g9zpWmq73xzlwFn%2Fuploads%2FWJwHoyWkmLZ0Qrqkj93V%2Fimage.png?alt=media&#x26;token=6224ed28-344b-48e9-94c6-a5143abd404b" alt=""><figcaption></figcaption></figure>
{% endtab %}

{% tab title="Details" %}

#### Message to Send

Select the message that will be sent after a player joins.
{% endtab %}
{% endtabs %}

## On Player Exit

{% tabs %}
{% tab title="About" %}

### On Player Exit

This rule sends a message each time a new player leaves an Experience.

<figure><img src="https://331512196-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F83PS3g9zpWmq73xzlwFn%2Fuploads%2FGewaSZXwdZewwLBtOXPU%2Fimage.png?alt=media&#x26;token=bd9b713b-4eef-47fe-9ed0-55e17dff31a3" alt=""><figcaption></figcaption></figure>
{% endtab %}

{% tab title="Details" %}

#### Message to Send

Select the message that will be sent after a player leaves.
{% endtab %}
{% endtabs %}

## Send Message

{% hint style="success" %}
This is the only rule that will has broadcast types.
{% endhint %}

{% tabs %}
{% tab title="About" %}

### Send Message

{% hint style="warning" %}
**UPDATED IN GAME MAKER 0.11**

This can direct a message sent from the Rules System to a more specific target.
{% endhint %}

This rule sends a message to the targets specified in the Broadcast Type field:

* **All**
* **Rules**
* **Specific tags** - add tags to broadcast to (and apply them to target objects)
* **Triggering actors**
* **Objectives (quests)**
* **Team** - select a team that has been defined in [Spawn Point](https://docs.sandbox.game/en/creator/game-maker/docs/behaviours/basic-logic/spawn-point-and-avatars-feature) behavior

{% hint style="info" %}
This rule makes the Game Rules system more compatible with gameplays that will use the new **team variable**.
{% endhint %}

<figure><img src="https://331512196-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F83PS3g9zpWmq73xzlwFn%2Fuploads%2FVCdqK2JLMdykvZfCXg32%2Fimage.png?alt=media&#x26;token=bc4f5030-8f24-4ec2-8259-3044567a2018" alt="" width="308"><figcaption></figcaption></figure>
{% endtab %}

{% tab title="Details" %}

#### Required Message

Select the incoming message to trigger the rule.

#### Message to send

Select the outgoing message to be sent once the rule is triggered. Use the broadcast type to define which targets will receive the message.
{% endtab %}
{% endtabs %}

## Send Message to \[SP] Actors

{% hint style="success" %}
This is the only rule that will communicate with **\[SP]** behaviours and components.
{% endhint %}

{% tabs %}
{% tab title="About" %}

### Send Message to \[SP] Actors

{% hint style="warning" %}
**NEW IN GAME MAKER 0.11**

This rule may be used to improve performance in multiplayer Experiences.
{% endhint %}

This rule allows you to send a message:

* from the server, including messages from \[MP] behaviours and components
* to the client, including \[SP] behaviours and components

<figure><img src="https://331512196-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F83PS3g9zpWmq73xzlwFn%2Fuploads%2FIFIWvGrBMAdoaoEFOgqy%2Fimage.png?alt=media&#x26;token=5f86b215-eea1-4be9-b854-36a9211e7f11" alt="" width="295"><figcaption></figcaption></figure>

{% hint style="info" %}
**MULTIPLAYER BASICS**\
In multiplayer Experiences, information is managed in two "layers":

* Server (synchronised)
  * player and object movements and collisions
  * spawned objects
  * variable data
  * quest data
  * interactive logic that must communicate with any of these
* Client (local)
  * stationary objects and their collisions
  * logic that can be managed off of the server for better performance
  * interactive logic that must communicate with any of these

Experiences play more smoothly when the server needs to manage less information.&#x20;

This rule may be used to design more efficient Experiences. It may also allow for more game mechanics and/or assets to be added. Always test thoroughly.
{% endhint %}
{% endtab %}

{% tab title="Details" %}

#### Required Message

Select the incoming message to trigger the rule.

#### Message to send

Select the outgoing message to be sent once the rule is triggered.
{% endtab %}
{% endtabs %}


---

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