tell me why
Blitz3D Forums/Blitz3D Beginners Area/tell me why
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| Why in the code below, do I get entity does not exist after deleting an emitter. The emiiter is deleted because its parent is removed, I get the error at these lines below. TurnEntity e\pivot, e\turnx#,e\turny#,e\turnz# MoveEntity e\pivot,0,0,e\movespeed# It should not try to move that e\pivot after its been deleted. I removed that instance of e.emitter. [\CODE] Function handleemitters() For e.emitter= Each emitter FLAGD=False If e\active Then ;decide if its time to spawn a dirt If e\spawntimer#<(gametimer#) And dirtcount=<maxdirt Then e\spawntimer#=(e\spawnrate#+gametimer#) Dirtcount=dirtcount+1 ;spawn dirt d.dirt=New dirt d\sprite=CopyEntity (e\hiddensprite) ShowEntity d\sprite d\xv#=e\xv# d\yv#=e\yv# d\zv#=e\zv# PositionEntity d\sprite,EntityX(e\pivot,1)+Rnd(-e\area#,e\area#),EntityY(e\pivot,1)+Rnd(-e\area#,e\area#),EntityZ(e\pivot,1)+Rnd(-e\area#,e\area#) d\forces=e\forces d\rotationinc#=e\rot# d\alpha#=e\alpha# d\decay#=e\decay# d\scalechange#=e\scalechange# d\mass#=e\mass# d\scale#=e\startscale# d\lifespan#=e\plifespan# d\lifetimer#=(gametimer#+d\lifespan#) EndIf ;do turns movements on emitter ;if parented.. follow parent TurnEntity e\pivot, e\turnx#,e\turny#,e\turnz# MoveEntity e\pivot,0,0,e\movespeed# ;see if emitter has lifespan if so check to see if it has expired EndIf ;IF ACTIVE If e\lifetime#<>0 Then If e\lifetime#<gametimer# Then flagd=True EndIf EndIf If e\parent Then If GetParent(e\pivot)=0 Then flagd=True EndIf EndIf If flagd=True Then FreeEntity e\HIDDENSPRITE FreeEntity e\pivot Delete e EndIf Next End Function [CODE\] |
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pseuso code if entityexhist=1 then TurnEntity e\pivot, e\turnx#,e\turny#,e\turnz# MoveEntity e\pivot,0,0,e\movespeed# endif explenation you are trying to rotate an objext after it's been deleted, this will never work. cus it's been deleted..... |
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| OK BUT HOW DOES IT GET TO THAT POINT AGAIN? after i delete e, the loop should go to the next e. correct? and then the next time i call this loop it would not include the deleted e. so can you explain for me. It seems to work also if I delete the NEXT e .. can you explain that.. here is the changed delete code If flagd=True Then FreeEntity e\HIDDENSPRITE FreeEntity e\pivot Delete After E Delete e EndIf Next That works with no problems.. why ? |
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| I hasd the sam problem with my asteroids. I'm pretty sure after you delete a type obkject, it goes to the end of the list. I had to create another type list, with a list of types to be deleted..or osmething.. i don't rememebr |
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| It goes to the end of the list? So you are saying it doesnt get deleted at all? How then can you keep a type list under control ? |
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This should work perfectlytype thing field a end type ; create some for i=1 to 5 t.thing=new thing t\a=i next show() ; delete one for t.thing=each thing if t\a=4 then delete t next show() waitkey end function show() print "----------" for i.thing=each thing print j+" - "+i\a j=j+1 next end function |
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| No, i mean the pointer goes to the end of the list. The item gets deleted, but the pointer to the current type goes to the edn of the list. |
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| Y? Well like i said once and object gets deleted and the program tries to move it an error occurs. Why because IT DOES NOT EXHIST ANYMORE! YOU DELETED IT! got that? am i clear enough? |
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| dark, i know that, knew that.. i dont need help understanding that you cant move non existing entities, but I also deleted the instance of that type along with the actual entity, my question was how is blitz getting to a point where it would try to look at a type instance again after it had been deleted. |
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| I would guess you are deleting a pivot which is needed later. Suppose two emitters share a pivot, and you do 'FreeEntity e\pivot' with one of them. The pivot entity is now gone. A later 'TurnEntity e\pivot...', where e is the other emitter, is an error. |
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| Im sure its simple.. each emitter has a seperate pivot. I cant seem to find the issue with it. ill rewrite the partical engine tomorrow. Thanks everyone, and Merry Christmas! |
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| RifRaf, my bad. I'm talking mince. It was when i added to the type list the pointer went to the end :) ops! Ok, well, if you creating a particle system, it is wiser to NOT delete things. Just simply re-use them. Set there active flag to 0 if they aren't being used. When you goto update, check for all the type objects for being active. If so, then update that object, if not, skip it. When it comes to generating a new object, look thru you list of particle objects to see if any aren't active. Then re-activate them. You will need to create the particles before hand tho, but it's is a good practice :) |
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