Serious unexplainable Performance Differences - got proof

Helmut_AUT · 06-09-2009, 07:15 PM

Okay, this gets to the point where I really have to believe the engine has code problems or design problems. I can't explain it any other way, and I would really appreciate if we can hear from the devs here.

Using a GF9600GT, everthing to low except textures (normal) and shadows (normal), VD 1200, Fillrate 100% at 1920x1200.

Now, the test:

On the small island in Utres, walk to the first wooden house in Strelka, the first on the right as you come up from the beach.

Drop your gun.

Walk up to the house facing NW and place yourself directly in front of a stretch of wooden wall with NO windows or anything in it. With your nose touching the house, so the house blocks everthing else, straight on.

Gives me 24 FPS.

Now, I move to the opposite side of the house, walk up to a bare stretch of wood wall, and do the same.

34 FPS.

That's a 40% frame difference. Looking at the SAME texture from the SAME distance with nothing else on the screen.

I really can only explain this by assuming that they are not properly culling background objects as they get blocked by other things. Because when you are looking SE at the house, behind it is mostly open ocean. When you are staring NW "trough the house" you are looking at the destroyed church.

I have no way to take apart the engine and know what BIS has done here, but I do know that 40% framerate difference looking at the same texture should not happen. Can someone throw this on the bugtracker please?

ECH · 06-09-2009, 07:35 PM

Your post would go a long way in helping explain your situation if your provided pics. What you need is:
-fraps which will allow you to either record it or screen shot the situation
-programs like Media Show Espresso allows you to convert videos to youtube
-Youtube will allow you to upload any video you created
-Image Shack will allow you to upload your screenshots and show them to the community

I say this because what you posted is interesting and hopefully more information is addressed and perhaps fixed.

Helmut_AUT · 06-09-2009, 08:08 PM

I have all that, but I don't have the time right now to prepare such a detailed report.

And anyway, the gist of it is simple: If the player is in front of an object with a simple texture that totally blocks his view, the framerate varies by 40%, seemingly dependent on what is BEHIND that object. Which makes no sense because if you are looking at the broad side of a house, nothing else should be rendered at all, so anything that is BEHIND the house shouldn't matter.

Or, in other words: Looking at the same piece of texture in game, so that it fills your screen, can give you 40% framerate difference. This makes no sense since it's the same graphical detail being rendered.

dale0404 · 06-09-2009, 09:14 PM

Ok you are onto something here. I did exactly what you said mate and here are the results. You can see the framerate in the top right of the pictures.

First picture is facing NW towards the church:

The second picture is facing SE towards the sea from the other side of the house:

So as you can there is certainly some performance drop!

Helmut_AUT · 06-09-2009, 09:33 PM

60% difference rendering the same piece of texture. Insane.

Steinfisch · 06-09-2009, 10:34 PM

The framerate does not only depend on the texture. The engine cannot always render all objects of a scene. This would result in a framerate under 1. So it must calculate which objects are completely outside the view frustum (the 3d space the player can see) which partially outside and which inside. This calculation leads to different results depending of your direction of sight. The more objects you can see, the slower the rendering.

Helmut_AUT · 06-09-2009, 10:41 PM

Steinfisch, I know that. In this case, you can only see one object, both times.

Steinfisch · 06-09-2009, 10:49 PM

...But the graphics engine don't know what you know. There can be different ways to calculate, and mistakes.

POTS · 06-10-2009, 12:20 AM

Quote:

Originally Posted by Steinfisch

...But the graphics engine don't know what you know. There can be different ways to calculate, and mistakes.

Thats exactly what they are trying to point out, massive problem with the graphics engine. This clearly displays that people are NOT getting the performance they should with the same amount of detail.

---------- Post added at 12:20 AM ---------- Previous post was at 12:15 AM ----------

This is called overdraw right? So this would mean that the graphics engine isn't properly communicating with the graphics cards. Therefor the graphics cards processing depth that you cant see. Which ultimately means that once again, BIS has not optimized correctly for the graphics cards.

Leopardi · 06-10-2009, 12:25 AM

Nice find. This could bring a nice fps boost if it was optimized correctly.

06-09-2009, 07:15 PM	#1
Helmut_AUT Gunnery Sergeant Join Date: Apr 2007 Posts: 424	Serious unexplainable Performance Differences - got proof Okay, this gets to the point where I really have to believe the engine has code problems or design problems. I can't explain it any other way, and I would really appreciate if we can hear from the devs here. Using a GF9600GT, everthing to low except textures (normal) and shadows (normal), VD 1200, Fillrate 100% at 1920x1200. Now, the test: On the small island in Utres, walk to the first wooden house in Strelka, the first on the right as you come up from the beach. Drop your gun. Walk up to the house facing NW and place yourself directly in front of a stretch of wooden wall with NO windows or anything in it. With your nose touching the house, so the house blocks everthing else, straight on. Gives me 24 FPS. Now, I move to the opposite side of the house, walk up to a bare stretch of wood wall, and do the same. 34 FPS. That's a 40% frame difference. Looking at the SAME texture from the SAME distance with nothing else on the screen. I really can only explain this by assuming that they are not properly culling background objects as they get blocked by other things. Because when you are looking SE at the house, behind it is mostly open ocean. When you are staring NW "trough the house" you are looking at the destroyed church. I have no way to take apart the engine and know what BIS has done here, but I do know that 40% framerate difference looking at the same texture should not happen. Can someone throw this on the bugtracker please?

06-09-2009, 09:14 PM	#4
dale0404 Gunnery Sergeant Join Date: Jun 2008 Posts: 475	Ok you are onto something here. I did exactly what you said mate and here are the results. You can see the framerate in the top right of the pictures. First picture is facing NW towards the church: The second picture is facing SE towards the sea from the other side of the house: So as you can there is certainly some performance drop! Last edited by dale0404; 06-09-2009 at 09:17 PM.

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06-09-2009, 07:35 PM	#2
ECH Private Join Date: Jun 2009 Posts: 10	Your post would go a long way in helping explain your situation if your provided pics. What you need is: -fraps which will allow you to either record it or screen shot the situation -programs like Media Show Espresso allows you to convert videos to youtube -Youtube will allow you to upload any video you created -Image Shack will allow you to upload your screenshots and show them to the community I say this because what you posted is interesting and hopefully more information is addressed and perhaps fixed.

06-09-2009, 08:08 PM	#3
Helmut_AUT Gunnery Sergeant Join Date: Apr 2007 Posts: 424	I have all that, but I don't have the time right now to prepare such a detailed report. And anyway, the gist of it is simple: If the player is in front of an object with a simple texture that totally blocks his view, the framerate varies by 40%, seemingly dependent on what is BEHIND that object. Which makes no sense because if you are looking at the broad side of a house, nothing else should be rendered at all, so anything that is BEHIND the house shouldn't matter. Or, in other words: Looking at the same piece of texture in game, so that it fills your screen, can give you 40% framerate difference. This makes no sense since it's the same graphical detail being rendered.

06-09-2009, 09:33 PM	#5
Helmut_AUT Gunnery Sergeant Join Date: Apr 2007 Posts: 424	60% difference rendering the same piece of texture. Insane.

06-09-2009, 10:34 PM	#6
Steinfisch Private First Class Join Date: Jun 2009 Location: Germany Posts: 32	The framerate does not only depend on the texture. The engine cannot always render all objects of a scene. This would result in a framerate under 1. So it must calculate which objects are completely outside the view frustum (the 3d space the player can see) which partially outside and which inside. This calculation leads to different results depending of your direction of sight. The more objects you can see, the slower the rendering.

06-09-2009, 10:41 PM	#7
Helmut_AUT Gunnery Sergeant Join Date: Apr 2007 Posts: 424	Steinfisch, I know that. In this case, you can only see one object, both times.

06-09-2009, 10:49 PM	#8
Steinfisch Private First Class Join Date: Jun 2009 Location: Germany Posts: 32	...But the graphics engine don't know what you know. There can be different ways to calculate, and mistakes.

06-10-2009, 12:25 AM	#10
Leopardi Gunnery Sergeant Join Date: May 2005 Location: Finland Posts: 499	Nice find. This could bring a nice fps boost if it was optimized correctly.

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