Hi, I’m actually trying to create spawners for different ennemies (which are displayed with sprites).
I tried this way : http://coronalabs.com/blog/2011/09/14/how-to-spawn-objects-the-right-way/
It does work with a regular image, but can’t make it work with sprites.
Anybody would know how?
Thank you!
Hi @nekozhead,
I recently posted a new tutorial on basic spawning which contains a module that you can download and modify.
http://coronalabs.com/blog/2014/11/04/tutorial-basic-spawning/
As for using sprites, this should be basically the same as spawning images. If there’s some issue with that, it might be how you’re creating the sprites (another topic to discuss in that case).
Best regards,
Brent
Hi Brent! Thank you so much for your fast answer! 
Tried the tutorial (really easy to understand by the way).
I just get this error though when calling spawnController(“start”,spawnParams) : main.lua:61:bad argument #2 to random (number expected, got nil)
stack traceback: [C]: in fonction random
main.lua 61: in function spawnItem
main.lua 89: in function spawnController
main.lua 110: in main chunk (this the line the controller is called)
i really don’t know why…is it because I haven’t set an event listener? I wanted to test it out and make sure it works before creating my other ennemies spawners…(and see if the sprites were working…they should be cause no error regarding them)
Thanks again for your help so far
Nekoz
Here’s my main if you wanna look at it :)
–
– main.lua
–
–Background Display
local background = display.newImage(“Graphics/skin.png”)
background.x = 240
background.y = 170
background:scale (0.6,0.6)
–SpriteSheet Setting
local sheetInfo = require “sprite”
local myImageSheet = graphics.newImageSheet(“Graphics/MarinSheet.png”,sheetInfo:getSheet())
local sequenceData = {
{name=“MarinAfly”, sheet = myImageSheet, start=sheetInfo:getFrameIndex(“MarinA_vole_01”),count=4,time=600,loopcount=0}
}
–Ennemy Display
–Mosqui = display.newSprite (myImageSheet,sequenceData)
–Mosqui.x = 250
–Mosqui.y = 250
–Mosqui:scale ( 0.6,0.6)
–Mosqui:setSequence(“MarinAfly”)
–Mosqui:play()
–Spawners
local spawnTimer
local spawnedObjects = {}
local spawnParams = {
xMin = 50,
xMax = 750,
yMin = 20,
yMax = 1100,
spawnTime = 200,
spawnOnTimer = 12,
spawnInitial = 4,
}
local function spawnItem (bounds)
local item = display.newSprite (myImageSheet,sequenceData)
item:setSequence(“MarinAfly”)
item:play()
item.x = math.random(bounds.xMin, bounds.xMax)
item.y = math.random(bounds.yMin, bounds.yMax)
spawnedObjects[#spawnedObjects+1] = item
end
local function spawnController(action, params)
if (spawnTimer and (action == “start” or action == “stop”))then
timer.cancel(spawnTimer)
end
if (action == “start”) then
local spawnBounds = {}
spawnBounds.xMin = params.xMin or 0
spawnBounds.xMAx = params.xMax or display.contentWidth
spawnBounds.yMin = params.yMin or 0
spawnBounds.yMax = params.yMax or display.contentHeight
local spawnTime = params.spawnTime or 1000
local spawnOnTimer = params.spawnOnTimer or 50
local spawnInitial = params.spawnInitial or 0
if (spawnInitial > 0) then
for n = 1, spawnInitial do
spawnItem(spawnBounds)
end
end
if (spawnOnTimer > 0) then
spawnTimer = timer.performWithDelay (spawnTime,function()spawnItem(spawnBounds); end,
spawnOnTimer)
end
elseif (action == “pause”) then
timer.pause(spawnTimer)
elseif (action == “resume”) then
timer.resume(spawnTimer)
end
end
spawnController(“start”,spawnParams)
Hi @nekozhead,
I recently posted a new tutorial on basic spawning which contains a module that you can download and modify.
http://coronalabs.com/blog/2014/11/04/tutorial-basic-spawning/
As for using sprites, this should be basically the same as spawning images. If there’s some issue with that, it might be how you’re creating the sprites (another topic to discuss in that case).
Best regards,
Brent
Hi Brent! Thank you so much for your fast answer!
Tried the tutorial (really easy to understand by the way).
I just get this error though when calling spawnController(“start”,spawnParams) : main.lua:61:bad argument #2 to random (number expected, got nil)
stack traceback: [C]: in fonction random
main.lua 61: in function spawnItem
main.lua 89: in function spawnController
main.lua 110: in main chunk (this the line the controller is called)
i really don’t know why…is it because I haven’t set an event listener? I wanted to test it out and make sure it works before creating my other ennemies spawners…(and see if the sprites were working…they should be cause no error regarding them)
Thanks again for your help so far
Nekoz
Here’s my main if you wanna look at it :)
–
– main.lua
–
–Background Display
local background = display.newImage(“Graphics/skin.png”)
background.x = 240
background.y = 170
background:scale (0.6,0.6)
–SpriteSheet Setting
local sheetInfo = require “sprite”
local myImageSheet = graphics.newImageSheet(“Graphics/MarinSheet.png”,sheetInfo:getSheet())
local sequenceData = {
{name=“MarinAfly”, sheet = myImageSheet, start=sheetInfo:getFrameIndex(“MarinA_vole_01”),count=4,time=600,loopcount=0}
}
–Ennemy Display
–Mosqui = display.newSprite (myImageSheet,sequenceData)
–Mosqui.x = 250
–Mosqui.y = 250
–Mosqui:scale ( 0.6,0.6)
–Mosqui:setSequence(“MarinAfly”)
–Mosqui:play()
–Spawners
local spawnTimer
local spawnedObjects = {}
local spawnParams = {
xMin = 50,
xMax = 750,
yMin = 20,
yMax = 1100,
spawnTime = 200,
spawnOnTimer = 12,
spawnInitial = 4,
}
local function spawnItem (bounds)
local item = display.newSprite (myImageSheet,sequenceData)
item:setSequence(“MarinAfly”)
item:play()
item.x = math.random(bounds.xMin, bounds.xMax)
item.y = math.random(bounds.yMin, bounds.yMax)
spawnedObjects[#spawnedObjects+1] = item
end
local function spawnController(action, params)
if (spawnTimer and (action == “start” or action == “stop”))then
timer.cancel(spawnTimer)
end
if (action == “start”) then
local spawnBounds = {}
spawnBounds.xMin = params.xMin or 0
spawnBounds.xMAx = params.xMax or display.contentWidth
spawnBounds.yMin = params.yMin or 0
spawnBounds.yMax = params.yMax or display.contentHeight
local spawnTime = params.spawnTime or 1000
local spawnOnTimer = params.spawnOnTimer or 50
local spawnInitial = params.spawnInitial or 0
if (spawnInitial > 0) then
for n = 1, spawnInitial do
spawnItem(spawnBounds)
end
end
if (spawnOnTimer > 0) then
spawnTimer = timer.performWithDelay (spawnTime,function()spawnItem(spawnBounds); end,
spawnOnTimer)
end
elseif (action == “pause”) then
timer.pause(spawnTimer)
elseif (action == “resume”) then
timer.resume(spawnTimer)
end
end
spawnController(“start”,spawnParams)