Today I finished making some improvements to the engine's built-in integration with the Tiled and the TMX file format:

• Implemented support for nested layer groups
• Fixed a crash that occured on maps with unset background color
• Added support for loading tilesets from external *.tsx files
• Enabled tilesets that use a single spritesheet image (both embedded and external)
• The render layers api (https://blog.ldk.dev/render-layers/) can now be used to set an explicit render order on individual map layers and objects (so you can blend your environment with non-map entities, like characters hiding in the scenery)
• Layers and objects can now be rendered with custom opacity values
• Enabled tint color for adjusting the color of objects and layers

We're getting pretty close to full support for every feature of the TMX map format!

The following features are still unsupported:

• Infinite maps
• Image layers
• Polygon and polyline objects
• Embedded text

I've added an experimental ECS::EntityRelations extension to the ECS to make it easier to model relationships between entities. It's usually best to avoid that pattern in gamedev, so the design of the framework will continue to discourage overusing it and turning your game into some kind of Rails application... but I've found that certain kinds of problems in games just cannot be reasonably modeled any other way. The exact API will probably change before it's settled, but for now we have this:

The EntityBuilder DSL now includes these three new methods: belongs_to, has_one, and has_many. Entities connected in this way will be loosely associated by their entity ID using a BelongsTo({ relation: :entity, id: nil }) component under the hood (it is automatically added to the entity on that side of the relationship).

You can name your relations anything you want - they do not have to match the name of any class. As long as the value of belongs_to[:id] on an association matches the ID of your entity, you can create as many virtual has_one and has_many relations as you like with different sets of filters, and the result set will include whatever mix of entities those filters match.

Example

components do
	Person({ name: "Unknown" })
	Score({ points: 0 })
end

Player = entity do
	belongs_to :team
	Person()
end

Goal = entity do
	belongs_to :team
	Score()
end

Team = entity do
	has_many :players, filter: [Person]
	has_one :goal, filter: [Score]
end

world :example_game do
	entity Player, name: "Alice", as: :alice
	entity Player, name: "Bob", as: :bob
	entity Team, as :nerds

	systems AssignTeams, UpdateScore
end

AssignTeams = system do
	filter Person
	tick do |args|
		entities.each do |player|
			player.team = world.nerds if player.team.nil?
		end
	end
end

UpdateScore = system do
	tick do |args|
		world.teams.each do |team|
			if team.goal.nil?
				goal = Goal.new({ score: 0 })
				goal.team = team
				world.entities << [goal]
			end
		end
	end
end

nerds = world.nerds

nerds.players #> [Player<id: 1, Alice>, Player<id: 2, Bob>]
world.alice.team #=> Team<id: 3, players: [Alice, Bob], goal: Goal<id: 4, score: 0>
nerds.goal #=> Goal<id: 4, score: 0, team: Team<id: 3, players: [Alice, Bob]>

Mouse input is now fully implemented, featuring

• Support for Left, right, and middle mouse buttons each withdown, up, pressed, and released states
• Mouse wheel
• Current position and delta position since the previous frame
• Option to grab the mouse cursor and keep it inside of the game window
• Option show or hide the mouse cursor
• Replacing the cursor with a custom sprite is demonstrated in examples/input_mouse

See demo:

The updated mouse input API is as follows:

# Mouse input API

Mouse.position # Current mouse cursor position (x & y)
Mouse.delta_position # Delta position since the previous frame

Mouse.cursor.show! # Show the mouse cursor
Mouse.cursor.hide! # Hide the mouse cursor

Mouse.cursor.grab! # Force the cursor to stay inside the game window
Mouse.cursor.release! # Allow the cursor to move outside of the window

Mouse.wheel # (x, y)
Mouse.buttons.[left|right|middle].[down?|up?|pressed?|released?]