Defold platformer engine.

You can use the extension in your own project by adding this project as a Defold library dependency. Open your game.project file and in the dependencies field under project add:

https://github.com/britzl/Platypus/archive/master.zip

Or point to the ZIP file of a specific release.

See an example of Platypus in action by running the grottoescape.collection of this project or try the HTML5 demo.

Use platypus.create() to create a Platypus instance. Use this to control a single game object. Each frame you need to call platypus.update() and platypus.on_message().

function init(self)
	self.platypus = platypus.create(config)
end

function update(self, dt)
	self.platypus.update(dt)
end

function on_message(self, message_id, message, sender)
	self.platypus.on_message(message_id, message)
end

Use platypus.left(), platypus.right(), platypus.up(), platypus.down() and platypus.move() to move the player. The movement will happen during the next call to platypus.update().

function init(self)
	self.platypus = platypus.create(config)
end

function update(self, dt)
	self.platypus.update(dt)
end

function on_message(self, message_id, message, sender)
	self.platypus.on_message(message_id, message)
end

function on_input(self, action_id, action)
	if action_id == hash("left") then
		self.platypus.left(250)
	elseif action_id == hash("right") then
		self.platypus.right(250)
	end
end

Platypus supports normal jumps when standing on the ground, wall jumps when in contact with a wall in the air and double jumps. You can also perform a "forced" jump that will perform a jump regardless of state. This can be useful when implementing rope mechanics and other such functions where there is no ground or wall contact.

Use platypus.jump() to perform a jump and platypus.abort_jump() to reduce the height of a jump that is already in progress.

function init(self)
	self.platypus = platypus.create(config)
end

function update(self, dt)
	self.platypus.update(dt)
end

function on_message(self, message_id, message, sender)
	self.platypus.on_message(message_id, message)
end

function on_input(self, action_id, action)
	if action_id == hash("jump") then
		if action.pressed then
			self.platypus.jump(800)
		elseif action.released then
			self.platypus.abort_jump(0.5)
		end
	end
end

Platypus uses either collision shapes or ray casts to detect collisions (configured when creating a Platypus instance). In both cases ray casts are used to detect wall and ground contact.

Platypus will send messages for certain state changes so that scripts can react, for instance by changing animation.

function init(self)
	self.platypus = platypus.create(config)
end

function update(self, dt)
	self.platypus.update(dt)
end

function on_message(self, message_id, message, sender)
	self.platypus.on_message(message_id, message)
	if message_id == platypus.FALLING then
		print("I'm falling")
	elseif message_id == platypus.GROUND_CONTACT then
		print("Phew! Solid ground")
	elseif message_id == platypus.WALL_CONTACT then
		print("Ouch!")
	elseif message_id == platypus.WALL_JUMP then
		print("Doing a wall jump!")
	elseif message_id == platypus.DOUBLE_JUMP then
		print("Doing a double jump!")
	elseif message_id == platypus.JUMP then
		print("Jumping!")
	end
end

Create an instance of Platypus. This will provide all the functionality to control a game object in a platformer game. The functions will operate on the game object attached to the script calling the functions.

PARAMETERS

• config (table) - Table with configuration values

The config table can have the following values:

• collisions (table) - Lists of collision groups and bounding box size (REQUIRED)
• debug (boolean) - True to draw ray casts
• gravity (number) - Gravity (pixels/s) (OPTIONAL)
• max_velocity (number) - Maximum velocity of the game object (pixels/s). Set this to limit speed and prevent full penetration of game object into level geometry (OPTIONAL)
• wall_jump_power_ratio_x (number) - Amount to multiply the jump power with when applying horizontal velocity during a wall jump (OPTIONAL)
• wall_jump_power_ratio_y (number) - Amount to multiply the jump power with when applying vertical velocity during a wall jump (OPTIONAL)
• allow_double_jump (boolean) - If double jumps are allowed
• allow_wall_jump (boolean) - If wall jumps are allowed

The collisions table can have the following values:

• separation (hash) - How to do collision separation. Use platypus.SEPARATION_SHAPES to separate using collision shapes and platypus.SEPARATION_RAYS to separate using ray casts. Default: platypus.SEPARATION_SHAPES
• ground (table) - List with collision group hashes for collision objects representing ground. Used when separating collisions using collision shapes.
• left (number) - Distance from game object center to left edge of collision shape. Used by ray casts to detect ground and wall contact and when separating collisions using rays.
• right (number) - Distance from game object center to right edge of collision shape. Used by ray casts to detect ground and wall contact and when separating collisions using rays.
• top (number) - Distance from game object center to top edge of collision shape. Used by ray casts to detect ground and wall contact and when separating collisions using rays.
• bottom (number) - Distance from game object center to bottom edge of collision shape. Used by ray casts to detect ground and wall contact and when separating collisions using rays.

RETURN

• instance (table) - The created Platypus instance

The instance table has all of the instance functions describe below in addition to the values from config (either provided values or defaults) and the following fields:

• velocity - The current velocity of the game object

You can modify any of the instance values at runtime to change the behavior of the platypus instance.

Update the Platypus instance. This will move the game object and send out state changes.

PARAMETERS

• dt (number) - Delta time

Forward received messages from the on_message lifecycle function to this instance function. This will handle collision messages and custom messages generated by the Platypus instance itself

PARAMETERS

• message_id (hash) - Id of the received message
• message (table) - The message data

Move the game object to the left during next update. This will override any previous call to instance.left() or instance.right() as well as the horizontal velocity of instance.move().

PARAMETERS

• velocity (number) - Amount to move left (pixels/s)

Move the game object to the right during next update. This will override any previous call to instance.left() or instance.right() as well as the horizontal velocity of instance.move().

PARAMETERS

• velocity (number) - Amount to move right (pixels/s)

Move the game object up during next update. This will override any previous call to instance.up() or instance.down() as well as the vertical velocity of instance.move().

PARAMETERS

• velocity (number) - Amount to move up (pixels/s)

Move the game object down during next update. This will override any previous call to instance.up() or instance.down() as well as the vertical velocity of instance.move().

PARAMETERS

• velocity (number) - Amount to move down (pixels/s)

Move the game object during next update. This will override any previous call to instance.left(), instance.right(), instance.up(), instance.down() and instance.move().

PARAMETERS

• velocity (vector3) - Amount to move (pixels/s)

Make the game object perform a jump. Depending on state and configuration, this can either be a normal jump from standing on the ground, a wall jump if having wall contact and no ground contact, or a double jump if jumping up and not falling down.

PARAMETERS

• power (number) - Initial takeoff speed (pixels/s)

Make the game object perform a jump, regardless of current state.

PARAMETERS

• power (number) - Initial takeoff speed (pixels/s)

Abort a jump by "cutting it short". This will reduce the vertical speed by some fraction.

PARAMETERS

• reduction (number) - Amount to multiply vertical velocity with

Check if the game object is standing on the ground

RETURN

• ground_contact (boolean) - True if standing on the ground

Check if the game object is in contact with a wall

RETURN

• wall_contact (boolean) - True if in contact with a wall

Check if the game object is falling. The game object is considered falling if not having ground contact and velocity is pointing down.

RETURN

• falling (boolean) - True if falling

Check if the game object is jumping. The game object is considered falling if not having ground contact and velocity is pointing up.

RETURN

• jumping (boolean) - True if jumping

Toggle debug draw of ray casts.

Sent once when the game object starts to fall

Sent once when the game object detects ground contact

Sent once when the game object detects wall contact

Sent when the game object jumps

Sent when the game object performs a wall jump

Sent when the game object performs a double jump

Configuration value to indicate that collision separation should be done using collision shapes.

Configuration value to indicate that collision separation should be done using ray casts.

• Grotto Escape tiles - Ansimuz (https://ansimuz.itch.io/grotto-escape-game-art-pack)