I simply want to pass the integer value “score” from one script to another.
I get the following error: attempt to perform arithmetic on field ‘score’ (a nil value)
coin.script
function init(self)
self.collected = false
self.score = 5
end
function on_message(self, message_id, message, sender)
if self.collected == false and message_id == hash("collision_response") then
self.collected = true
local offset = vmath.vector3(0, 20, 0)
go.animate(go.get_id(), "position", go.PLAYBACK_ONCE_FORWARD, vmath.vector3(0, 900, 0), go.EASING_INOUTSINE, 0.5, 0, update_score)
elseif message_id == hash("start_animation") then
pos = go.get_position()
go.animate(go.get_id(), "position.y", go.PLAYBACK_LOOP_PINGPONG, pos.y + 24, go.EASING_INOUTSINE, 0.75, message.delay)
end
end
function update_score()
msg.post("level/score#gui","add_score", { score = 5 })
end
score.gui_script
-- how fast the score counts up per second
local score_inc_speed = 100
function init(self)
-- the target score is the current score in the game
self.target_score = 0
-- the current score being counted up towards the target score
self.current_score = 0
-- the score as displayed in the hud
self.displayed_score = 0
-- keep a reference to the node displaying the score for later use below
self.score_node = gui.get_node("score")
end
local function delete_star(self, star)
-- star has finished animation, delete it
gui.delete_node(star)
end
local function fade_out_star(self, star)
-- fade out the star before deletion
gui.animate(star, gui.PROP_COLOR, vmath.vector4(1, 1, 1, 0), gui.EASING_INOUT, 0.2, 0.0, delete_star)
end
local function spawn_stars(self, amount)
-- position of the score node, to be used for placing the stars
local p = gui.get_position(self.score_node)
-- distance from the position where the star is spawned
local start_distance = 0
-- distance where the star stops
local end_distance = 240
-- angle distance between each star in the star circle
local angle_step = 2 * math.pi / amount
-- randomize start angle
local angle = angle_step * math.random()
for i=1,amount do
-- increment the angle by the step to get an even distribution of stars
angle = angle + angle_step
-- direction of the star movement
local dir = vmath.vector3(math.cos(angle), math.sin(angle), 0)
-- start/end positions of the star
local start_p = p + dir * start_distance
local end_p = p + dir * end_distance
-- create the star node
local star = gui.new_box_node(vmath.vector3(start_p.x, start_p.y, 0), vmath.vector3(30, 30, 0))
-- set its texture
gui.set_texture(star, "star")
-- set to transparent
gui.set_color(star, vmath.vector4(1, 1, 1, 0))
-- fade in
gui.animate(star, gui.PROP_COLOR, vmath.vector4(1, 1, 1, 1), gui.EASING_OUT, 0.2, 0.0, fade_out_star)
-- animate position
gui.animate(star, gui.PROP_POSITION, end_p, gui.EASING_NONE, 0.55)
end
end
function update(self, dt)
-- check if the score needs to be updated
if self.current_score < self.target_score then
-- increment the score for this timestep to grow towards the target score
self.current_score = self.current_score + score_inc_speed * dt
-- clamp the score so it doesn't grow past the target score
self.current_score = math.min(self.current_score, self.target_score)
-- floor the score so it can be displayed without decimals
local floored_score = math.floor(self.current_score)
-- check if the displayed score should be updated
if self.displayed_score ~= floored_score then
-- update displayed score
self.displayed_score = floored_score
-- update the text of the score node
gui.set_text(self.score_node, "score "..self.displayed_score)
-- set the scale of the score node to be slightly bigger than normal
local s = 1.3
gui.set_scale(self.score_node, vmath.vector3(s, s, s))
-- then animate the scale back to the original value
s = 1.0
gui.animate(self.score_node, gui.PROP_SCALE, vmath.vector3(s, s, s), gui.EASING_OUT, 0.2)
-- spawn stars
--spawn_stars(self, 4)
end
end
end
function on_message(self, message_id, message, sender)
if message_id == hash("add_score") then
self.target_score = self.target_score + message.score
end
end
