Shooting Meteors

Now it's time to shoot some meteors.
In this section we will create bullets and implement the logic required to destroy meteors and earn points.

---

Creating the Bullet Behaviour

First, create the bullet behaviour in behaviours/bullet.lua:

local health = require("states.health")

return {
    init = function(state)
        state.speed = state.speed or 400 -- Bullet speed (default: 400)
        state.force_y = -state.speed -- Apply upward force
    end,

    tick = function(state)
        -- Destroy bullet when it leaves the screen
        if state.y < -16 then
            sucata.scene.destroy(state)
        end

        -- Get all meteors in the scene
        local meteors = sucata.scene.get_entities_by_tag("meteor")

        for _, id in ipairs(meteors) do
            local meteor = sucata.scene.find_by_id(id)

            if meteor and sucata.math.overlapping({
                x = state.x - 8,
                y = state.y - 8,
                width = 16,
                height = 16
            }, {
                x = meteor.x - 16,
                y = meteor.y - 16,
                width = 32,
                height = 32
            }) then
                -- Damage the meteor
                health.remove(meteor)

                if meteor.health <= 0 then
                    sucata.events.emit("meteor_destroyed", meteor)
                    sucata.scene.destroy(meteor)
                end

                -- Destroy the bullet
                sucata.scene.destroy(state)
                break
            end
        end
    end
}

Register the behaviour in behaviours/init.lua:

return {
    ...
    Bullet = require("behaviours.bullet"),
}

---

Creating the Bullet Entity

Now create the bullet entity in entities/bullet.lua:

local function bullet(x, y)
    return {
        state = {
            x = x,
            y = y
        },

        behaviours = {
            Behaviours.Bullet,      -- Bullet logic
            Behaviours.ApplyForces, -- Apply movement forces
            Behaviours.DrawSprite   -- Render the bullet
        }
    }
end

return bullet

---

Creating the Shooter Behaviour

Now we will allow the player to shoot bullets.

Create the file behaviours/shooter.lua:

local bullet = require("entities.bullet")

return {
    tick = function(state)
        if sucata.input.is_pressed("space", "enter") then
            sucata.scene.spawn(bullet(state.x, state.y - 16))
        end
    end
}

Register the behaviour in behaviours/init.lua:

return {
    ...
    Shooter = require("behaviours.shooter"),
}

---

Adding the Shooter to the Player

Now add the shooter behaviour to the player entity in entities/player.lua:

local function player(x, y)
    return {
        state = {
            x = x,
            y = y
        },

        behaviours = {
            Behaviours.Player,   -- Player movement
            Behaviours.Shooter,  -- Shooting logic
            Behaviours.DrawSprite -- Render player
        }
    }
end

return player

Note Behaviours are executed in order. The player logic runs first, followed by shooting logic, and finally rendering.

---

Now when you run the game, it should look like this: