Blitz Problem

When running my Blitz program in Windowed mode it has started stuttering instead of being nice and smooth. All was fine yesterday and I haven`t changed anything in my system. What could be causing this? How annoying!

Jason.

I found this when I enabled a second monitor and the window was just ever so slighly overlapping on to the second monitor...it's a long shot.

Which flavour of Blitz? All Blitz programs? What's the smallest example you can post which shows the problem? What else is running in the background?
Are you running a .exe or from the Blitz IDE? If from the IDE are you in debug or non-debug mode?
etc etc etc

Thanks Grey, didn`t work though :(

I`m using B3D, nothing different is running in the background as far as I can see and I am running from the IDE. All is fine in fullscreen mode though. The same problem occurs with debug off so that is not the problem.

Jason.

All Blitz programs? What's the smallest example you can post which shows the problem? What happens when you run as a .exe? What happens when you run the samples supplied with B3D?

The smallest program that I could show would be a simple graphics moving from left to right with the main loop being something really basic like,

While not keyhit(1)
cls

x=x+1
drawimage shape,x,100

flip
wend

All Blitz programs are doing this, samples and exe`s included. As mentioned this was not a problem yesterday and I have not installed anything new or changed anything in my system.

Jason.

You never know if somthing was installed silently, malware or not. It sounds like there's a high priority task in the background. This is where knowledge about system tasks is useful. Alternatively there may be some webpages with infos about good , bad and/or ugly processes. This way using the Task Manager makes sense.

I think the younger your OS is, the the higher the number of system processes put. Noless, you should have a list of OS processes and you should also have an idea about all other processes due to their name or file-path. Try to find a description of all tasks and processes that are unknown.

And of course make sure to use latest antivirus versions.

I think it could be malware as well. Have you run something like ad-aware? See if anything is clocking up CPU in task-manager which doesn't look familiar (or search for the processes or post them here).

I run both AdAware and Spybot and Avast Anti Virus and nothing is showing up. No new tasks seem to have been added either. It`s quite puzzling.

Jason.

http://www.answersthatwork.com/

^^ Go through everything in your task list and check it off that list.

Also go to Start>>Run, "msconfig">>Startup tab - check what's being launched at startup.

You say you haven't changed anything in your system. Check system restore to see if a restore point has been set which might coincide with the start of the problems you've got.

Make sure you antivirus software is set to do a FULL system scan. They normally don't, by default.

Checked startup, nothing different there. Ran AntiVirus in deep scan mode, all was well. System restored to a previous point. Same problem.

The only other thing I`ve done which I assumed would`nt be the cause is changed my lcd monitor connection from VGA to DVI but I fail to see how this could be the problem I will check it out though just to be sure.

Jason.

Another long shot. Do you do the seti@home or other such programs? If you were downloading, and are now processing, and have the right settings. That -might- cause this.

It only happens to blitz apps? Have you tried things like blitz apps? Run through all the games that came with windows?

I had this problem with my old ATI X1300....

bet it's the cable ;-)

Cygnus, was there a way around it? Was it only when using a DVI cable or also with VGA? Were you using a lcd monitor or did you just mean it was you graphics card?

Crap! Just tried the VGA cable and it work fine in Windowed mode again. Now I don`t know what to do. The DVI cable gives me a better picture and works fine in fullscreen mode but why isn`t it working properly in Windowed mode?

Any suggestions or possible solutions?

Jason.

Always the way.

lol

Did you try any other refresh rates?

Also, what video card do you have? In the ATI Catalyst Control Panel there are some other settings that could potentially affect the operation:
"Reduce DVI frequency on high-resolution displays"
"Alternate DVI operational mode"

If you have an ATI card, look for those and see if toggling them makes any difference.

I have an NVidia card so those settings are not an option. Are there any similar NVidia settings that may work? I couldn`t see any but someone a little more technical might know of something... (I hope)

Strange how the DVI cable cannot seem to cope with the data transfer as quickly as the VGA one does. I know that there are diffeent types of DVI cable, could this be the problem? I think that the one that came with the monitor is a DVI-D one.

(Edit)
It only seems to happen when my desktop is in 1440x900 but this mode works fine via VGA. Not sure what else to try.

Jason.

Should using the DVI connection on my card operate slower than a VGA connection? If 1440x900 runs well in VGA why is it stuttering in DVI? Is it most likely a timing issue or something else?

Jason.

I found having changed from VGA CRT to DVI TFT that instead of

flip

do a

vwait
flip(false)

No idea why this is better because in theory they should be the same, but it seems to reduce tearing and keep everything smooth.

Thanks for the advice but still no luck :( I was hopeful for a moment though.

BTW nice to see you around again Rob. How`s your helicopter game going?

Jason.

Are you using 2d drawing / text functions? If so, try disabling them.

Have you just updated Blitz3d at all? My game chugged like crazy with the last update and I had to go back to the previous version.

...The other thing is it just sounds like part of the card driver has been trashed or corrupted in some way. Full uninstall and clean install would be worth a try.

No I haven`t updated Blitz (I went back to a previous version just to check) and have also reinstalled my graphic card drivers to be sure. Still no luck.

I have also tried not using 2D drawing and text functions, still no luck :(

Jason.

There may be some weirdness caused by the lack of vertical blanking period when using DVI. I haven't the foggiest idea how Blitz implements the vwait command, or how this may be affected by the lack of a real vertical blank event.

It may be something Blitz is doing wrong. After all, most other games work fine without stuttering, so their implementation of "sync to frame" works perfectly well with DVI.

It may also be nVidia's driver at fault. It is a bit of an edge case, with so few people playing windowed games requiring of smooth updates.

One last thing I can think of is those pesky 'VIA' 4in1 AGP drivers for the motherboard..check in your contol panel that you don't have any devices showing with a question mark.

It's a long shot but I've had unbearable choppy graphics performance twice because of some odd problem deciding to happen with this VIA stuff.

OK, I will give that a try. Thanks for mentioning it.

Jason.

As far as I know, the Vsync signal is sent to a register of the cpu by the graphics card. It's them up to the program to make use of it. Contrary to EG the Atari ST which allowed a Vsync-triggered Hardware-Interrupt, PCs must poll the register. (Correct me if I'm wrong)

To me this DVI cable problem sounds like a driver bug. Don't know much about DVI, but I guess it's a digital transfer of data from PC to Monitor. If so, a certain transfer speed is required. Maybe it's not fast enough. Or maybe there's bad snyching of multiplexed data on that cable, in both directions.

Did you update the driver and/or search some NVidia forums for this topic?

Yes, and I tried using some alternative Omega drivers instead of the NVidia ones but it still appeared jerky.

The problem is like when the hard disk is reading when you try to run a Blitz program and it slows to a crawl but my hard drive is not actually reading anything. The problem goes away complelety with the VGA cable so it`s definetly releated to the DVI cable\connection.

I`m going to have a scan through the NVdia forums now.

Jason.