Recycling of Types

Blitz3D Forums/Blitz3D Beginners Area/Recycling of Types

BlackJumper

(Posted 2003) [#1]

I have a problem with my approach to some code I am working on:

If KeyDown(Key_M) Then
   For colonycounter = 1 To 5
   colony.Drone = CreateDrone( Rand(30), Rand(30) )
   Next
EndIf


....

Type Drone
	Field xpos#,zpos#,DroneHandle, droneName$, droneState, homeTunnel% ;, Destination
	Field seeky%, speed#, energy%
End Type
;==================================================
Function CreateDrone.Drone(itsx#, itsz#)
  d.Drone = New Drone
  DroneCount = DroneCount + 1
... etc....

I later wish to recycle the drones which have completed a task, but I have had lots of problems if I try to FreeEntity (does this do what it says in the Help - the example doesn't work as described on my system !)

this pseudocode illustrates my approach...

Function UpdateDrones()
   For thisDrone.Drone = Each Drone
   If thisDrone\energy% < 0 Then
       FreeEntity thisDrone\droneHandle
   EndIf
...

End Function

At some points in related code I pivot objects to the drones and then free the pivot when the drone completes the mission. Again I would like to recycle the objects to avoid wasting resources.

At the moment I am using HideEntity, but I expect that as the demo progresses, this will lead to system slowdown. I have also noticed some anomalies in the collision detection when this is the case - some of the drones 'leak' out of the bounding scenery, which I assume is due to 'tweened' updates of the world getting progressively stretched due to processing large numbers of entities.

.... So ....

Is my approach (i.e. creating New drones via a function) the problem, or can I get at the entities and Free them so that I can forget about them ? Or do I need to use a 'droneInUse' flag (within the Type) and work with that within my main UpdateDrones() function ?

Over to you...

Ross C

(Posted 2003) [#2]

well, why don't you just free the entity, then delete the object

FreeEntity thisdrone\dronehandle
delete thisdrone.drone

then create a new one when you need it, or am i missing something?

try this

Graphics3D 800,600
SetBuffer BackBuffer()


light=CreateLight()
eship=CreateSphere()
PositionEntity eship,-30,0,0

camera=CreateCamera()
PositionEntity camera,0,0,-20

Gosub setup

While Not KeyHit(1)

	If KeyDown(200) Then Gosub createnewship
	
	
	
	Gosub updateships
	
	UpdateWorld
	RenderWorld
	Text 0,0," press up key to generate enemy craft"
	Flip
Wend
	
End


.updateships
	For enemy.ship=Each ship
	enemy\y=enemy\y-enemy\speed
	PositionEntity enemy\entity,enemy\x,enemy\y,0
	If enemy\y<-9 Then
						FreeEntity enemy\entity:Delete enemy.ship; free the entity then delete the type object
	End If
	Next
Return



.createnewship
	enemy.ship=New ship
	enemy\entity=CopyEntity(eship); copy the eship entity
	enemy\x=Rnd(-10,10)
	enemy\y=9
	enemy\speed=Rnd(0.1,0.5)
Return

.setup
	Type ship
	Field entity
	Field x,y#
	Field speed#
	End Type
Return

BlackJumper

(Posted 2003) [#3]

Actually, it was me that was missing something.... the 'delete' command. I'm too used to programming languages which garbage collect for me !!

cheers for the swift response, joker

And now a quick related question... if I use this method and the memory allocated to drones gets fragmented, will BB3D compact the space or internally recycle it at some point ? Or will the resources be lost after all ?

DJWoodgate

(Posted 2003) [#4]

I believe the situation is that when you create a new instance of a type the type list is expanded in memory. However the reverse is not true, when you delete a type no memory is freed thus avoiding any fragmentation problems. (obviously deleted instances would get reused in this scenario when you create new instances).