Events

To add interactivity, Odyc.js provides a simple event system.
It lets you trigger actions or modify the game state.

---

Template Events

🔎 Available event types

There are nine types of events:

• onCollideStart — called when the player collides with the element, occurs before dialog, sound and end
• onCollide — called when the player collides with the element
• onEnterStart — called when the player steps onto a tile containing the element, occurs before dialog, sound and end
• onEnter — called when the player steps onto a tile containing the element
• onLeave — called when the player leaves a tile containing the element
• onScreenEnter — called when the element enters the visible screen
• onScreenLeave — called when the element leaves the screen
• onTurn — called at the end of each turn, after the player attempted to move
• onMessage - called via the sendMessageToCells method

createGame({
	templates: {
		x: {
			onCollideStart() {
				alert('collide start')
			},
			onCollide() {
				alert(1)
			},
			onEnterStart() {
				alert('enter start')
			},
			onEnter() {
				alert(2)
			},
			onLeave() {
				alert(3)
			},
			onTurn() {
				alert(4)
			},
			onScreenEnter() {
				alert('hi')
			},
			onScreenLeave() {
				alert('bye')
			},
			onMessage() {
				alert('5 / 5')
			}
		}
	}
})

---

Target of the event

When an event is triggered, the affected object is passed as a parameter. You can use it to modify or remove the element dynamically.

createGame({
	templates: {
		x: {
			onCollide(target) {
				target.remove()
			}
		}
	}
})

---

📋 Available properties

Property / Method	Type	Description	Read-only
solid	boolean	Whether the object is passable	No
visible	boolean	Whether the object is visible	No
sprite	number | string	Changes the object’s appearance	No
sound	string| object	Changes the sound played on interaction	No
dialog	string | string[]	Modifies the dialog text	No
end	string | string[]	Triggers a custom game ending	No
symbol	string	The character representing the object in the map	Yes
position	[number, number]	[x, y] position of the object on the grid	Yes
isOnScreen	boolean	true if the object is currently visible on screen	Yes
remove	() => void	Removes the element from the game	—
moveTo	(x, y) => void	Moves the element to the specified position	—

Example: change a property

Let’s create a character who says “Hello” the first time, then “Hello again” afterwards:

createGame({
	templates: {
		x: {
			dialog: 'Hello',
			onCollide(target) {
				target.dialog = 'Hello again'
			}
		}
	}
})

Remove an element

To remove an element’s properties when touched, use the remove() method:

createGame({
	templates: {
		x: {
			onCollide(target) {
				target.remove()
			}
		}
	}
})

Move an element

To move an element to a new position, use moveTo(x, y):

createGame({
	templates: {
		x: {
			onCollide(target) {
				target.moveTo(3, 2)
			}
		}
	}
})

onMessage

onMessage differs slightly from other events in that you trigger it yourself via game.sendMessageToCells. The onMessage method is called with two arguments: the event target and the message:

const game = createGame({
	templates: {
		x: {
			sprite: 1,
			onMessage(target, message) {
				if (message === 'turnOff') target.sprite = 0
				else if (message === 'turnOn') target.sprite = 1
			}
		}
	}
})

game.sendMessageToCells({ symbols: 'x' }, 'turnOff')

---

Player Events

🎮 player.onInput

The onInput event is triggered in the following cases:

• when a direction key is pressed (or a swipe on a touch screen),
• or when an action key is used (Enter, Space, or a tap on mobile).

createGame({
	player: {
		onInput(input) {
			console.log(input)
		}
	}
})

The function receives an input argument, which can be one of: UP, RIGHT, DOWN, LEFT, or ACTION.

---

player.onTurn

The onTurn event is called at the end of each turn, after the player attempted to move.

createGame({
	player: {
		sprite: '0',
		onTurn(player) {
			player.sprite = Math.floor(Math.random() * 9)
		}
	}
})

The function receives a player argument similar to game.player