Help?! :)

BlitzMax Forums/BlitzMax Programming/Help?! :)

Docster

(Posted 2008) [#1]

BlitzMax 1.30

Hello ppl!

I'm pretty new when it comes to coding in blitzbasic (MAX). The reason I'm asking here, is because my text scroller seems to flicker/stutter. The flickering is kinda random, but it's really annoying. And I don't know why this small code should flicker like this.. Could any one give me a hint or a sollution of this problem? I have tried several ways, but the scroller just seems to shake or something. I got the same problem in every application I make in BlitzMax.

My specs are as follows:

CPU: AMD Athlon X2 6400+ dual core (3.2Ghz)
Graphics: EVGA e-GeForce 8800 GTS
Memory: 2GB
OS: Windows XP Pro
Latest DirectX/Soundcard/Graphics drivers

- The scroller code -

SuperStrict

Const W:Int = 640		' Height
Const H:Int = 480		' Width
Const D:Int = 0		' Depth (0 = window mode)

Graphics W,H,D

Global scrollList:TList = New TList
Global movespeed:Float=2.0

HideMouse

Type scroller
	Field x:Float
	Field y:Float
	Field char:String
		
	Method update()
		For Local s:scroller = EachIn scrollList
			s.x:-movespeed
			DrawText s.char,s.x,s.y
			If s.x<-50 Then scrollList.remove s
		Next
	End Method
	
	Function Create:scroller(x:Float,y:Float,char:String)
		Local s:scroller = New scroller
		s.x=x
		s.y=y
		s.char=char
		scrollList.addlast s
	End Function
End Type

' Scroller text
Local text:String

text="                          Hello ppl! This small scroller is kinda flickering and stuttering.. "
text:+" Why is it stuttering and flickering in BlitzMax??? ........................... "

Local wait:Int = 0
Local letter:Int = 0
Local s:scroller = New scroller

Repeat
	Cls
	If wait>5
		Local tmp:String=Mid(text,letter,1)
		Local s:scroller = New scroller
		s.Create(640,400,tmp)
		wait=0
		letter:+1		
		If letter > Len(text) Then letter=0
	EndIf
	wait:+1
	s.update
	Flip
Until KeyHit(KEY_ESCAPE)
End

-- End code --

Thanks in advance,
Docster

Grey Alien

(Posted 2008) [#2]

It's smooth in fullscreen mode but in windowed mode it stutters because you are using Flip with no param which uses -1 which means BMax sets up a 60Hz timer which is probably not in sync with your desktop refresh rate. Try Flip 1 instead which uses VSync, that's smooth on mine. However, eventually you'll need to invest some time into getting a decent timing routine sorted out.

Docster

(Posted 2008) [#3]

Thanks Grey Alien for your fast reply.. :)

Well, it flickers in windowed and full screen mode here. And I can't find out why it does. No CPU spikes eighter.

After writting a small FPS routine, it looks like it's jumping from 60 to 61 FPS. Which tells me that this thingy is out of sync as you said. Now I just need to write a decent timing routine, which I never have done before. I'll try it out. :)

Grey Alien

(Posted 2008) [#4]

welcome. So Flip 1 still flickered?

ziggy

(Posted 2008) [#5]

Flip(1) should do the trick as Grey alien said

Docster

(Posted 2008) [#6]

Yes, the flip 1 worked. :) But, sometimes there are some flickering. But, it's much better than -1 .. :) Thanks alot! :D

MGE	(Posted 2008) [#7]

"Yes, the flip 1 worked. :) But, sometimes there are some flickering. But, it's much better than -1 .. :) Thanks alot! :D"

Welcome to proper pc game coding. Where jitters, quirks, hiccups, etc, are quite common. :)

Docster

(Posted 2008) [#8]

Well, there seems to be a problem with flip 1 too. If I set "3D settings->Adjust image settings to preview->Use my preference emphasizing" to Performance, in the NVIDIA Control Panel, it seems like flip 1 doesn't comply any longer. Any work around for this one? Or could anyone help me creating a timer routine that works? I don't seem to get the timer function to work properly.

Thanks. :)

MGE	(Posted 2008) [#9]

you probably turned off vysnc from your 3d settings. You should probably see "tear" once in a while as the image draws on itself.

Research "fixed rate logic" in the search link, that's what you need to do. :)

Docster

(Posted 2008) [#10]

Tnx! I'll have a look! :D