Game Manager

Now we will create a Game Manager, responsible for managing core game systems such as:

• Meteor spawning
• Player health
• Player points

---

Meteor Spawner

First, we will create a system that spawns a new meteor every 5 seconds.

Create the file behaviours/meteor_spawner.lua:

local meteor = require("entities.meteor")

return {
    init = function(state)
        state.spawner_time = state.spawner_time or 5 -- Time between meteor spawns

        -- Create a timer that spawns meteors
        sucata.time.create_timer(function ()
            sucata.scene.spawn(meteor())
        end, {
            time = state.spawner_time,
            loop = true,
            auto_start = true
        })
    end
}

Register the behaviour in behaviours/init.lua:

return {
    ...
    MeteorSpawner = require("behaviours.meteor_spawner")
}

---

Game Manager Entity

Now we will create the Game Manager entity.

Create the file entities/game_manager.lua:

return {
    state = {},
    behaviours = {
        Behaviours.MeteorSpawner
    }
}

Spawn the Game Manager in main.lua:

local game_manager = require("entities.game_manager")

sucata.scene.spawn(game_manager)

---

Player health

Now we will implement the player's health system.

First, create a state module in states/player_health.lua:

local function remove(state)
    if not state.health then -- Safe state modification
        return
    end

    state.health = state.health - 1
end

return {
    remove = remove
}

Note States are modules that contain logic for modifying entity state. They can be called from any behaviour.

Now create the behaviour behaviours/player_health.lua:

local health = require("states.health")

return {
    init = function(state)
        state.health = state.health or 3 -- Default player health

        sucata.events.on(state, "meteor_reached", function(_)
            health.remove(state)

            if state.health <= 0 then
                -- Game over logic (to be implemented)
            end
        end)
    end
}

Register the behaviour in behaviours/init.lua:

return {
    ...
    PlayerHealth = require("behaviours.player_health")
}

Add it to the Game Manager in entities/game_manager.lua:

return {
    state = {},
    behaviours = {
        Behaviours.PlayerHealth,
        Behaviours.MeteorSpawner
    }
}

---

Player Points

Next, we will implement the player scoring system.

Create the state module states/player_points.lua:

local function add_points(state, points)
    if not state.points then -- Safe state modification
        return
    end

    state.points = state.points + points
end

return {
    add_points = add_points
}

Now create the behaviour behaviours/player_points.lua:

local player_points = require("states.player_points")

return {
    init = function(state)
        state.points = 0 -- Initial score

        sucata.events.on(state, "meteor_destroyed", function(_)
            player_points.add_points(state, 5)
        end)
    end
}

Register the behaviour in behaviours/init.lua:

return {
    ...
    PlayerPoints = require("behaviours.player_points")
}

Update the Game Manager in entities/game_manager.lua:

return {
    state = {},
    behaviours = {
        Behaviours.PlayerHealth,
        Behaviours.PlayerPoints,
        Behaviours.MeteorSpawner
    }
}

---

Drawing the UI

Finally, we will draw the player UI on the screen.

Create the behaviour behaviours/draw_player_ui.lua:

return {
    draw = function(state)
        sucata.graphic.draw_text({
            text = "Health: " .. state.health,
            x = 960 - 16,
            y = 10,
            font_size = 16,
            align = "right"
        })

        sucata.graphic.draw_text({
            text = "Points: " .. state.points,
            x = 960 - 16,
            y = 40,
            font_size = 16,
            align = "right"
        })
    end
}

Register the behaviour in behaviours/init.lua:

return {
    ...
    DrawPlayerUi = require("behaviours.draw_player_ui")
}

Add the UI behaviour to the Game Manager:

return {
    state = {},
    behaviours = {
        Behaviours.PlayerHealth,
        Behaviours.PlayerPoints,
        Behaviours.MeteorSpawner,
        Behaviours.DrawPlayerUi -- Rendering should happen last
    }
}

The UI should now appear like this: