Dynamic factories

Setup

This example shows how to change the prototype game object used by a factory component. All prototype bullets are stored in a collection and referenced as a collection proxy. The collection proxy is never loaded, but it will ensure that the bullet prototypes are included in the build even though they are not immediately used by a factory. Another alternative is to load bullet prototypes using Live Update.

ship

The red ship at the bottom. Contains:

A Sprite component with the spaceship image.
A Factory component to spawn bullet game objects. This component has the Dynamic Protoype option checked.
A Collection Proxy component referencing a collection containing all bullet types
A Script component to handle spawning of bullets.

All bullets are added in the bullets.collection:

The bullets.collection is referenced from the dynamic.collection as a collection proxy:

Scripts

dynamic.script

function init(self)
    msg.post(".", "acquire_input_focus")

    -- a list of different bullet prototypes
    self.bullets = {
        "/example/flame.goc",
        "/example/lightning.goc",
        "/example/rock.goc",
    }
    -- the currently used bullet prototype
    self.bullet_index = 1

    -- shoot one bullet per second
    -- animate the bullet up 1000 pixels and then delete it
    timer.delay(0.2, true, function()
        local id = factory.create("#bulletfactory")
        local to = go.get_position(id)
        to.y = to.y + 1000
        go.animate(id, "position", go.PLAYBACK_ONCE_FORWARD, to, go.EASING_LINEAR, 1.5, 0, function()
            go.delete(id)
        end)
    end)
end

function on_input(self, action_id, action)
    -- mouse or spacebar
    if (action_id == hash("touch") or action_id == hash("action")) and action.pressed then
        -- next bullet prototype, wrap around to the first
        self.bullet_index = self.bullet_index + 1
        if self.bullet_index > #self.bullets then
            self.bullet_index = 1
        end

        -- unload current prototype
        factory.unload("#bulletfactory")

        -- set a new prototype
        local prototype = self.bullets[self.bullet_index]
        factory.set_prototype("#bulletfactory", prototype)
    end
end

If you want to play with these examples, you can get the project on Github.

Do you want to see more examples? Why not write a few yourself and submit a pull request? We love contributions.

GITHUB