Usage example for saga.lua

example_scene_manager.lua

local saga = require('lib.saga')

local function switch_scene(self, next_scene)
    -- Unload the current scene (if there is one)
    if self.scene then
        local proxy_id = '#' .. self.scene
        
        print('Unloading proxy: ' .. proxy_id)
        msg.post(proxy_id, 'disable')
        msg.post(proxy_id, 'final')
        msg.post(proxy_id, 'unload')

        local message_id, message, sender = saga.take(hash('proxy_unloaded'))
        print('Proxy unloaded: ' .. proxy_id)
    end
    
    -- Load the next scene
    local proxy_id = '#' .. next_scene
    
    print('Loading proxy: ' .. proxy_id)
    msg.post(proxy_id, 'load')
    
    local message_id, message, sender = saga.take(hash('proxy_loaded'))
    print('Proxy loaded: ' .. proxy_id)
    msg.post(sender, 'init')
    msg.post(sender, 'enable')
    
    self.scene = next_scene
end

function init(self)
    self.scene = null
    self.saga = null
    
    -- Load the first scene
    msg.post('.', 'goto_scene', {name = 'main_menu'})
end

function on_message(self, message_id, message, sender)
    if self.saga then
        self.saga = saga.continue(self.saga, message_id, message, sender)
    else
        if message_id == hash('goto_scene') then
            self.saga = saga.create(switch_scene, self, message.name)
        end
    end
end