Difference between revisions of "love.update"

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* [[parent::love]]
 
* [[parent::love]]
 
* [[World:update]]
 
* [[World:update]]
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* [[variable]]
 
[[Category:Callbacks]]
 
[[Category:Callbacks]]
 
{{#set:Description=Callback function used to update the state of the game every frame.}}
 
{{#set:Description=Callback function used to update the state of the game every frame.}}

Revision as of 15:43, 18 June 2013

Callback function used to update the state of the game every frame.

Function

Synopsis

love.update( dt )

Arguments

number dt
Time since the last update in seconds.

Returns

Nothing.

Examples

Run a function called think inside a table called npc once per second.

dtotal = 0   -- this keeps track of how much time has passed
function love.update(dt)
   dtotal = dtotal + dt   -- we add the time passed since the last update, probably a very small number like 0.01
   if dtotal >= 1 then
      dtotal = dtotal - 1   -- reduce our timer by a second, but don't discard the change... what if our framerate is 2/3 of a second?
      npc.think()
   end
end

Change a variable var at a constant rate (+/- 3 per second in this example).

var = 10   -- arbitrary starting value
rate = 3   -- change to change the rate at which the var is changed
function love.update(dt)
   if love.keyboard.isDown("down") then   -- reduce the value
      var = var - (dt * rate)
   end
   if love.keyboard.isDown("up") then   -- increase the value
      var = var + (dt * rate)
   end
end

See Also


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