Why some lines are not executed properly? (SOLVED)

Questions
1

Hey, I am writing some functions but some lines are not taking effect unless I wrap them with a delay like this: timer.delay(0.02, false, function() self.fallen_to_the_ground = false end) .
Just using self.fallen_to_the_ground = false sometimes is not executed. I call the methods containing these lines from the on_message function. What could be the reason for this? Is the delay wrapping a recommended or non-harmful approach?
Thank you

2

Nope, not at all. You don’t have to do that.

Are you sure the message isn’t delayed somehow?

This is technically not possible. (Also it is not a function, you are setting a value(boolean) to variable. ) You’re probably doing something wrong somewhere.
Be sure you’re not overwriting this variable somewhere else, maybe in the update() function?

Maybe if you can share more of the code, we can identify the issue

3

Thank you for the answer. I’m developing a flappy bird clone and it works correctly. It’s just that I have some lines wrapped and I do not think that should be necessary. Here is the code:

 local GameManager = require("_Scripts.GameManager")
local gui_url = msg.url("main:/GUI#GUI")

function init(self)
	msg.post(".", "acquire_input_focus")
	self.velocity = 0 -- Vertical velocity
	self.gravity = -980 -- Gravity strength
	self.jump_force = 400 -- Jump strength
	self.rotation_factor = 0.0015
	self.lerp_speed = 20
	self.fallen_to_the_ground = false
	self.start_pos = go.get_position(".")
	msg.post(gui_url, "get_game_ready")
end

local function clamp(value, min, max)
	return math.max(min, math.min(max, value))
end

function update(self, dt)
	print(GameManager.get_game_state(), " ", self.fallen_to_the_ground)
	if GameManager.get_game_state() == "game_started" or 
	(GameManager.get_game_state() == "fallen" and not self.fallen_to_the_ground) then
		self.velocity = self.velocity + self.gravity * dt

		local pos = go.get_position()
		pos.y = pos.y + self.velocity * dt
		go.set_position(pos)

		local target_angle = clamp(self.velocity * self.rotation_factor, -0.7, 0.7)
		local target_rotation = vmath.quat_rotation_z(target_angle)

		local current_rotation = go.get_rotation()
		local new_rotation = vmath.slerp(self.lerp_speed * dt, current_rotation, target_rotation)
		go.set_rotation(new_rotation)
	end
end

local function increase_score()
	GameManager.set_player_score(GameManager.get_player_score() + 1)
	msg.post(gui_url, "set_score", {score = GameManager.get_player_score()})
end

local function start_game(self)
	GameManager.set_game_state("game_started")
	msg.post(gui_url, "start_game")
	self.velocity = self.jump_force
end

local function reset_game(self)
	GameManager.set_player_score(0)
	
	go.set_position(self.start_pos)
	go.set_rotation(vmath.quat_rotation_z(0))
	self.velocity = 0  
	GameManager.set_game_state("waiting_to_start")

	--timer.delay(delay,repeating,callback)
	timer.delay(0.02, false, function() sprite.play_flipbook("#sprite", "PlayerAnim") end)
	timer.delay(0.02, false, function() self.fallen_to_the_ground = false end)
	timer.delay(0.02, false, function() GameManager.set_game_state("waiting_to_start") end)
	timer.delay(0.02, false, function() msg.post(gui_url, "get_game_ready") end)
end

local function death(self)
	GameManager.set_game_state("fallen")
	sprite.play_flipbook("#sprite", "PlayerFallen")
	msg.post(gui_url, "end_game")
end

function on_message(self, message_id, message, sender)
	-- Handle collisions
	if message_id == hash("trigger_response") and 
	(message.group == hash("pipe") or message.group == hash("ground")) then
		death(self)
	end
	if message_id == hash("trigger_response") and message.group == hash("ground") and
	not self.fallen_to_the_ground then
		self.velocity = 0
		self.fallen_to_the_ground = true
		print("Fallen to the ground")
	end
	if message_id == hash("trigger_response") and message.group == hash("between") 
	and message.enter then
		increase_score()
	end
end

function on_input(self, action_id, action)
	if action_id == hash("LeftClick") and action.pressed then
		if GameManager.get_game_state() == "game_started" then
			self.velocity = self.jump_force
		elseif GameManager.get_game_state() == "waiting_to_start" then
			start_game(self)
		elseif GameManager.get_game_state() == "fallen" and self.fallen_to_the_ground then
			print("Resetting game!") -- Debugging
			reset_game(self) -- Now fully resets in one click
		end
	end
end
4

My first guess is that you are calling reset_game() from on_input instead of on_message. This might be causing the issue. I don’t think on_input is the right place to check if it has ‘fallen.’ The default input settings include a repeat delay and a repeat interval. I suggest posting a message for resetting instead.

This is not related, but you don’t have to wrap everything separately. You can do this once if you have to:

timer.delay(0.02, false, function()
	 sprite.play_flipbook("#sprite", "PlayerAnim") 
	 self.fallen_to_the_ground = false
	 GameManager.set_game_state("waiting_to_start")
	 msg.post(gui_url, "get_game_ready") 
	end)

I don’t understand the logic behind doing the same thing over and over again here:


	--timer.delay(delay,repeating,callback)
	timer.delay(0.02, false, function() sprite.play_flipbook("#sprite", "PlayerAnim") end)
	timer.delay(0.02, false, function() self.fallen_to_the_ground = false end)
	timer.delay(0.02, false, function() GameManager.set_game_state("waiting_to_start") end)
	timer.delay(0.02, false, function() msg.post(gui_url, "get_game_ready") end)


	--timer.delay(delay,repeating,callback)
	timer.delay(0.02, false, function()
	 sprite.play_flipbook("#sprite", "PlayerAnim") 
	 self.fallen_to_the_ground = false
	 GameManager.set_game_state("waiting_to_start")
	 msg.post(gui_url, "get_game_ready") 
	end)
	timer.delay(0.02, false, function() self.fallen_to_the_ground = false end)
	timer.delay(0.02, false, function() GameManager.set_game_state("waiting_to_start") end)
	timer.delay(0.02, false, function() msg.post(gui_url, "get_game_ready") end)

Edit:

Also, you are setting it to true here. I don’t know why or when you are posting the message, so you might be overwriting it.

	if message_id == hash("trigger_response") and message.group == hash("ground") and
	not self.fallen_to_the_ground then
		self.velocity = 0
		self.fallen_to_the_ground = true
		print("Fallen to the ground")
	end
5

That makes sense. I did not realize it was on the on_input actually so let me fix that and share the result.
Thank you

6

Actually after checking the code again my approach seems fine (at least this is the approach I would take with other engines like Unity or Godot). My lack of understanding on execution process of Defold could be the problem. I’ll go with the delay as once all written in the same function it is not looking messy, till I really understand the main cause behind it

7

There are Flappy Bird examples available on GitHub for Defold that you can check out:

1 Like
8

Thank you but I was able to solve it. The problem was the death function being called a few times instead of one. By adding a flag, I was able to solve the problem.
How do I mark the question as solved?

9

You can just edit the topic and add (SOLVED), like I did for you here :blush: