sync rate, fastsync and sync combination failure

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mr Handy

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Location: out of TGC

Posted: 23rd Mar 2012 10:53 Edited at: 23rd Mar 2012 10:54

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Hi.
My pseudo (source is huge) code is like this:

+ Code Snippet

sync on
sync rate 30
set display mode x,y,32,1
make camera 1
make camera 2
make camera 3
do
sync mask camera 2^1:fastsync
sync mask camera 2^2:fastsync
sync mask camera 2^3:fastsync
sync mask camera 2^0
sync
loop

FRAPS and "screen fps()" says 45

What Iam doing wrong?

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Green Gandalf

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Playing: Malevolence:Sword of Ahkranox, Skyrim, Civ6.

Posted: 23rd Mar 2012 13:44

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Quote: "What Iam doing wrong?"

Don't know. But shouldn't this

+ Code Snippet

sync mask camera 2^1:fastsync
sync mask camera 2^2:fastsync
sync mask camera 2^3:fastsync
sync mask camera 2^0
sync

be this

+ Code Snippet

sync mask camera 2^1:fastsync
sync mask 2^2:fastsync
sync mask 2^3:fastsync
sync mask 2^0
sync

?

I can't reproduce your problem. I get a steady 27-30 with this:

+ Code Snippet

sync on
sync rate 30
set display mode desktop width(),desktop height(),32,1
make camera 1
make camera 2
make camera 3
do
sync mask 2^1:fastsync
sync mask 2^2:fastsync
sync mask 2^3:fastsync
sync mask 2^0
text 20, 20, str$(screen fps())
sync
loop

Perhaps fraps is counting the fastsyncs as well? What does DBPro report? An FPS around 10 or 11 perhaps?

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Millenium7

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Posted: 23rd Mar 2012 15:17

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I had the same problem and I think the solution (which you already have in your code) was to set vsync on

Check it's not being forced off in your graphics card options
Another temporary workaround would be to include a check that runs every 1000ms to see if the FPS rate is higher than 61, and if it is then reduce the sync rate by 1

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mr Handy

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Location: out of TGC

Posted: 23rd Mar 2012 20:50 Edited at: 23rd Mar 2012 20:51

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Vsync forced on.

The fun thing is, that I've run GG's example on other PC and it worked properly. Maybe there is something I missed in my code, that has influence on framerate. I'll check tomorrow. But definetely I am using sync scheme as Green Gandalf posted. ~Mystrey~

edit:
I can understand if I have LOWER framerate than was set, bu HIGHER?!

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Fallout

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Location: Basingstoke, England

Posted: 23rd Mar 2012 21:15 Edited at: 23rd Mar 2012 21:17

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I'm pretty sure setting a sync rate just causes the code behind 'sync' to wait for a set period of time. It's probably using a timer which isn't accurate on your machine in that specific scenario.

If you need a fixed 30fps, you could probably code it yourself with PERFTIMER(), e.g.

+ Code Snippet

sync on
sync rate 0
set display mode x,y,32,1
make camera 1
make camera 2
make camera 3

timeStart as double integer 
ticksPerLoop as double integer

`Work out how many perf ticks elapses in 1/30th of a second
timeStart = PERFTIMER()
wait 1000
ticksPerLoop = (PERFTIMER()-timeStart)/30

do
   timeStart = PERFTIMER()
   sync mask camera 2^1:fastsync
   sync mask camera 2^2:fastsync
   sync mask camera 2^3:fastsync
   sync mask camera 2^0
   sync
   `Wait until 1/30th of a second has elapsed
   while PERFTIMER()-timeStart < ticksPerLoop
   endwhile   
loop

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Green Gandalf

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Playing: Malevolence:Sword of Ahkranox, Skyrim, Civ6.

Posted: 23rd Mar 2012 21:56

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Quote: "I can understand if I have LOWER framerate than was set, bu HIGHER?! "

As I suggested before, perhaps FRAPS is counting the fastsyncs as well, so if your sync rate was 11 (excluding fastsync) then FRAPS might report 44 if it was including the fastsyncs. Just a guess as I don't know what FRAPS does.

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mr Handy

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Location: out of TGC

Posted: 23rd Mar 2012 23:17

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@Fallout
Perftimer works 100%!!! Thanks!

@Green Gandalf
Just uninstalled FRAPS. Nothing changes.
Also I have noticed (in short):
sync rate 30 = result 30-45
sync rate 60 = result 60-75
~60 on maximum "in screen" objects.
both times +15 frames!
In my engine I am using this scheme:

Quote: "1. camera 1 - texture (objects)
2. camera 2 - depth (objects)
3. camera 3,4 - super bloom (render quads)
5. paste image 4 (I think it better than make one more quad IMHO)
6. sync camera 0 (pasted image + text)"

So I want to know, why such things happens.

P.S. My own PC did 30 FPS with your code. So it works correct.

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Fallout

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Posted: 23rd Mar 2012 23:38

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No problemo. I love PERFTIMER().

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