Threads and load pixmap causing problems

BlitzMax Forums/BlitzMax Programming/Threads and load pixmap causing problems

AdamRedwoods

(Posted 2010) [#1]

Hi,

I've been struggling over this problem where I've been trying to load in images as a thumbnail and get them to display. I've created the code so that the loop is in it's own thread, so as we're loading the images in a folder, the code can go and do something else. Seems to work fine sometimes, and other times it will crash randomly on me. Seems to crash less in Debug mode.

I've spent long hours isolating the problem, and I've come up with that it's something in the LoadPixmap. I've tried playing with streams but those seem to be ok. I've played with image size-- smaller files seem to do ok. Files over 500kb or so (family albums) tend to crash after a little while.

I've set up this code, and things are really screwy on my system (WinVista64)-- so I'm sure there's mistakes, but the problem still exists.

I've also noticed that if I add more garbage collectors, I can sometimes make the problem more isolated.

Anyways, I think there's a problem that's beyond my code.
I've also tried using Brucey's FreeImage, and I get the same random crashes.

The crashes are usually the code locking up with no errors. In debug mode, the code sometimes works (at least crashes less often).

I'd appreciate any help, and any suggestions for what the problem may be. It'd clear my sanity to get this working without random crashes.

The code (excuse the mess):

'' threaded

SuperStrict

'' 
Framework BRL.Max2D
Import brl.GLMax2d
Import brl.Standardio
Import BRL.EventQueue
Import BRL.Event
Import BRL.Timer
Import brl.threads
Import brl.GLGraphics
Import brl.jpgloader
Import brl.pngloader
Import brl.bmploader
'Import brl.Pixmap

'SetGraphicsDriver D3D9Max2DDriver()
'SetGraphicsDriver GLMax2DDriver()
Global g:TGraphics = GLGraphics( 950, 600, 0, 60, GRAPHICS_BACKBUFFER )
Global canvas:TMax2DGraphics = TMax2DGraphics.Create( g,GLMax2DDriver() )

Global desktopw:Int = 950
Global desktoph:Int = 600


Global iconSize:Int = 50 ''size of icons

Global filelist:String[]
Local startnum:Int =0

Global storedimage:TStoredimage = New TStoredimage

Global thumbmutex:TMutex = CreateMutex()
Global threadthumb:TThread = New TThread
Global mainmutex:TMutex = CreateMutex()

Global stopthread:Int=0

''
''___TYPES
Global storedpixmap:TPixmap[] = New TPixmap[150]

Type TStoredimage
	''only one needed
	Field total:Int
	Field name:String[]
	Field pixmap:TPixmap[]
	Field threadload:Int[]
	Field threadon:Int
	Global thismutex:TMutex
	
	Method addPixmap(p:TPixmap,i:Int)
		''use for threaded
		''adding mutex doesn't stop the exception access error
		
		If( i>=total)
			pixmap = pixmap[..total+2]
			'storedpixmap = storedpixmap[..total+2]
			threadload = threadload[..total+2]
			total :+1
		EndIf
		
		If(p)
			pixmap[i] = New TPixmap
			pixmap[i] = p
			threadload[i]=1 ''now its loaded
		EndIf
		
	EndMethod
	Method getPixmap:TPixmap(i:Int)
		If(pixmap[i])
			Return pixmap[i]
		EndIf
	EndMethod
	Method isValid:Int(i:Int)
		''drawit doesn't like mutexes
		If(i>=total) Return 0
		If(pixmap[i] And threadload[i])
			Return 1
		Else
			Return 0
		EndIf

	EndMethod
	Method  resetAll()
		total =0
		name=New String[1]
                pixmap = New TPixmap[1]
		'storedpixmap=New TPixmap[1]
		threadload=New Int[1]
	EndMethod
	Method  New:TStoredimage()
		thismutex= CreateMutex()
		resetAll()
		threadon=0
	EndMethod
EndType

''____main loop
Local i:Int=0
Local ii:Int =0
Local begin:Int =0
Local startdir:String =CurrentDir()
Repeat
	'WaitSystem()
	PollSystem()

	If (PollEvent()) Then
		''Print EventID()
		Select EventID()
		Case EVENT_APPTERMINATE
			stopthread=1
			End
		Case EVENT_WINDOWCLOSE
			stopthread=1
			End
		Case EVENT_KEYDOWN
			Select EventData()
			Case( KEY_ESCAPE)
				stopthread=1
				End
			Case( KEY_SPACE)
				begin=1
				stopthread =1
			Case( KEY_N)
				begin =1
				stopthread=1
				startdir = "G:/_pix/_Personal_photos/Hawaii_Oct_2009"
			EndSelect

		EndSelect		
	EndIf

	''my refresher
	ii:+1
	If( ii>50000)
		If(begin)
			stopthread=0
			GetThumb(startdir)
			begin=0
		EndIf
		DrawIt()
		ii=0
		GCCollect() ''something is eating up memory, this keeps it lean and faster too
	EndIf
Forever
End

''
''____DRAWIT in our main thread
''
Function DrawIt()
	Local isize:Int = iconSize+5
	Local p:TPixmap
	Local img:TImage =CreateImage(iconSize,iconSize,0,DynamicIMAGE)
	Local border:Int = 5
	Local x:Int=0, y:Int=0
	Local xnew:Int, ynew:Int
	Local width:Int = desktopw - 5
	Local height:Int = desktoph - 5
	Local n:Int
	
	SetGraphics ( canvas )
		SetClsColor(0,0,0)
		Cls
		
		For n=0 To (height*width/isize)
			If (y*isize > height-isize) Exit
			If (x*isize > width-isize) 
				y=y+1
				x=0
				If (y*isize > height-isize) 
					Exit
				EndIf
			EndIf

			xnew = x*isize 
			ynew = y*isize
			 
			If(storedimage.isvalid(n))
				xnew = xnew + (iconSize -storedimage.getPixmap(n).width)*0.5
				ynew = ynew + (iconSize -storedimage.getPixmap(n).height)*0.5
				'p = storedimage.getPixmap(n)
				'DrawPixmap(p, xnew+border, ynew +border) ''why is this eating up memory?

				SetColor (255,255,255)
				SetBlend SOLIDBLEND
				DrawImage LoadImage(storedimage.getPixmap(n)), xnew+border, ynew +border

			Else
				SetColor 30,30,30
				DrawRect(xnew+border, ynew +border, iconSize,iconSize)
			EndIf
			x=x+1
		Next
		Flip

EndFunction

''
''_____ GET THUMB
Function GetThumb(cd:String)

	WaitThread2(threadthumb)
	
	Local files:String[]
	Local list:String[]
	Local a:String
	Local supersize:Int = 50
	Local lx:Int=0

	
	files=LoadDir(cd)
	lx = files.length
	list = New String[lx*supersize+1]
	
	Local i:Int=0
	For Local j:Int = 0 To supersize-1 ''make a really long list
		For a = EachIn files
			'Print a
			If (CheckFileType(cd+"/"+a) )
				list[i] = cd+"/"+a
				i=i+1
			EndIf
		Next
	Next
	
	If(Not list) Return

	'''''___________threaded
	If(Not ThreadRunning (threadthumb))
		Print "thread"
		storedimage.threadon=1
		threadthumb=CreateThread( GetThumbThread, list )
		DetachThread(threadthumb)
	EndIf

EndFunction

''____our loader thread
Function GetThumbThread:Object(obj:Object)
	'LockMutex (thumbmutex)
	Local list:String[] = String[](obj)
	
	Local num:Int =0
	For num = 0 To list.length-1
		If (stopthread) Exit
		If (list[num])		
				'storedpixmap[num] = GetThumbStream(list[num])		
				''store the image here
				storedimage.addPixmap(GetThumbStream(list[num]) ,num)
		EndIf		
	Next

	'UnlockMutex thumbmutex

	Return Null
EndFunction


Function GetThumbStream:TPixmap(file:String=Null)
	If(Not file) Return Null
	
	Local p:TPixmap=New TPixmap
	Local fi:TPixmap = New TPixmap	
	Local st:Int = MilliSecs()
	Local bank:TBank = New TBank

Print"load "+file

	bank=LoadBank(file)
	'fi = LoadPixmap(file)

Print "loaded "+file

	fi = LoadPixmap(Bank)
Print "inbank"

	If(Not fi) Return Null
	
	p = ResizePixmap(fi,iconSize,iconSize)

	'GCCollect()
Print"GC"
	
	LockMutex ThumbMutex
	Print "timer:"+ (MilliSecs() - st)
	UnlockMutex ThumbMutex
	
	Return p
EndFunction


Function CheckFileType:Int (url:String)
	Local v:Int=1
	Local s:String
	s = ExtractExt(url)
	If s="png" Or s="jpg" Or s="gif" Or s="bmp" Or s="jpeg"
		v=1
	Else
		v=0
	EndIf
	Return v
End Function

''does mutex work? does waitthread work?
Function WaitThread2:Int(t:TThread)
	While (ThreadRunning (t))
		'
	Wend
	Return 0
EndFunction

If there are mistakes caught in the code (I consolidated and trimmed this code from other files) I'll update the above code, but even in my cleaner code I had random crashes.