Low FPS with ocean-sky horizon view at high altitude

[msduran 1]

Hi Steve.

 

I've been playing around with Fixer 2.9... overall results are very good. Thanks for the development.

 

However, I noticed an issue while flying over the ocean yesterday.

 

I took off from TBPB and during the climb my FPS was around 30 below 10,000 ft when looking outside from the cockpit, or from an outside camera (Spot, Locked spot). When I was above 20,000 ft, my FPS gradually decresed until I established 38,000 ft and my FPS was around 18.

 

Oddly, this performance lost ONLY occurred if I had an ocean-sky horizon in my field of view. if I looked slighty up (so I'd see just sky) ou slightly down (so I could see only land or water), my FPS got back to 30!!!

 

Then, during the descent, bellow 10,000 my FPS got back to normal around 30, no matter where I looked at.

 

The links bellow can illustrated the issue...

 

1. ocean-sky into field of view - low FPS

https://drive.google.com/open?id=0B3Pq5EQeDYFibFpMY0x2RGliRm8

 

2. looking down, water still visible - normal FPS

https://drive.google.com/open?id=0B3Pq5EQeDYFialdiTlhVU1Jnekk

 

3. during descent bellow 10,000 ft, sky-ocean ino view (clouds play no role in this issue) - normal FPS again

https://drive.google.com/open?id=0B3Pq5EQeDYFialdiTlhVU1Jnekk

 

I set up a test scenario to find a workaround for this issue:

 

1. Launch the simulator at an airport near the coast (SBRJ rwy 20L, for example).

2. Slew the aircraft (anyone, it doesn't matter) upward with FPS counter on the screen.

3. Watch the FPS count and altitude... the issue appears at or above 15,000 ft.

4. Look backwards to the land... FPS go normal.

 

After that, I played with every single option in the fixer, but i didn't succeed.

 

But then, I realized that I could try changing Water Effects inside FSX and voilà...

 

Water Effects 1.x - Normal FPS and performance above 15,000 ft with ocean-sky horizon.

Water Effects 2.x - Poor FPS and performance above 15,000 ft with ocean-sky horizon.

 

According to FSX manuals...

 

1.x has no reflections:

·         The lowest 1.x level does the basic shader.

·         The mid 1.x level adds an animated detail texture.

·         The highest 1.x level adds some specular effects (like sun)

2.x adds a 2nd pass to get reflections 

·         2.low reflects only the clouds and has a little more complicated shader – it can be a good compromise

·         2.med adds scenery, eg terrain and custom objects

·         2.hi adds Autogen (trees, generic objects ) and basically reflects the entire scene, which costs a lot

 

I must emphasize that this issue doesn't occur with land-sky horizon in the field of view, or just land, ocean or sky... you must have ocean-sky horizon at or above 15,000 ft.

 

Since my Water Effects was set to Low 2.x, I had this issue at every flight neat a coast line.

 

Steve, have you notice this before??? Is this an expected behavior??? Is there any workaround, but moving sliders?

 

Best regards,

 

Duran.

 

 

 

[SteveFx 258]

I haven't noticed anything, but I will take a look

[walterzach 2]

..the same to me,  dramatically frameloss across the ocean.

I solved that for me using the FSWaterConfigurator..!

[SteveFx 258]

Well no particular issues for me. 

 

Clearly if there are dense clouds then looking at the horizon will cause the maximum amount of overdraw which costs a lot with SGSS, but I don't see that in your screen shot.  I get no change in FPS switching from water 1.x to 2.x at that altitude with no clouds but that just tells me that that my system is CPU limited at that point.

 

At any point your fps is determined by the either the CPU or GPU and the latter primarily depends on screen size, GPU, SGSS setting, density of clouds currently in view.

 

A simple test is to turn off SGSS and see what happens.  If the frame rate increases then the system was GPU limited - if it doesn't change then it was CPU limited.

 

Its also worth disabling the  fixer water shader changes - just go into debug and untick water shader and see what happens.

[Pe11e 812]

I had that issue with HI DEF wave textures, for example from REX. Installed NORMAL DEF textures and no issue. Check all OceanHeight20FieldLayer.dds files in Texture folder, mine are 2.6MB, and HI DEF are over 20mb as I can recall.

[msduran 1]

Well no particular issues for me. 

 

Clearly if there are dense clouds then looking at the horizon will cause the maximum amount of overdraw which costs a lot with SGSS, but I don't see that in your screen shot.  I get no change in FPS switching from water 1.x to 2.x at that altitude with no clouds but that just tells me that that my system is CPU limited at that point.

 

At any point your fps is determined by the either the CPU or GPU and the latter primarily depends on screen size, GPU, SGSS setting, density of clouds currently in view.

 

A simple test is to turn off SGSS and see what happens.  If the frame rate increases then the system was GPU limited - if it doesn't change then it was CPU limited.

 

Its also worth disabling the  fixer water shader changes - just go into debug and untick water shader and see what happens.

 

 

Hi Steve.

 

1. I'll try disbling water shader and see what happens.

 

2. This issue has NO relation to cloud density or coverage. The test scenario I've described above can be replicated with ANY weather theme and condition... Tried "Clear Skies" and the issue keeps happening.

 

3. If it is just a matter of cloud density, how could we explain the difference in performance seen with a sky-ocean horizon in relation to land-ocean horizon, considering cloud density was the same in both situations? Futhermore, sky-ocean horizon would have very little to process (single landclass, simple terrain mesh, no autogen), in contrast to a sky-land horizon (different landclasses, complex terrain mesh and some autogen), so we would expect a better perfornance when facing a sky-ocean horizon than a sky-land one.

 

Best regards,

Duran.

[Pe11e 812]

@msduran

 

I forgot to mention that issue was happening over particular altitude like in your case. Check my above post.

[msduran 1]

I had that issue with HI DEF wave textures, for example from REX. Installed NORMAL DEF textures and no issue. Check all OceanHeight20FieldLayer.dds files in Texture folder, mine are 2.6MB, and HI DEF are over 20mb as I can recall.

 

Hi Pe11e.

 

Those files are 1,336 KB on my disk... nothing special.

Thanks for the advice.

 

Duran. 

[SteveFx 258]

Duran

 

I said that I didn't think it was cloud related as there weren't many in view! I am going on one screenshot for a problem I don't experience. 

 

My suggestion was to first disable SGSS to determine whether the fps is limited by CPU or GPU as that may help understand the issue.

 

Then if its GPU disable the shader changes to see whether the change there have an effect (but I doubt it!)

 

I recall that there are issues with 32bit water wave animation -so check if using REX

 

Also make sure that Texture Max Load matches the texture sizes in use, don't use textures bigger than the limit.

 

Steve

[msduran 1]

Hi Steve.

 

More info about performance loss and the ocean-sky horizon and water effects 2.x...

 

1. Actually, SGSS IS the culprit for the FPS drop when an ocean-sky horizon is into view. You are right!

 

2. This performance drop also occurs with DX9 and SGSS. For some reason, however, it is barely noticeable.

 

3. DX10 seems to aggravate this performace drop with SGSS. It happens with water shaders on OR off. Why this condition (an ocean-sky horizon) has such an impact in frame rate remains to be explained.

 

A pity I can't achieve the same image quality of 4xSGSS (NVI) using only the AA modes available in fixer, in some aircrafts (737 NGX, for example).

 

But overall balance with DX10 and fixer is positive, for sure.

 

Best regards, 

Duran.

[SteveFx 258]

 SGSS shows us that the issue is the GPU - it doesn't mean SGSS is the problem in this scenario - its just a big user of GPU resources which we can turn off.

 

The fact that it only occurs with water in view suggests that it relates to the processing of water which must be consuming a lot of GPU time somehow. There are many more water tiles as you look towards the horizon to be processed although they don't drive many pixels as output.

 

With SGSS off this water processing load isn't enough to have an impact (as the GPU has space capacity)and similarly with the simple 1.x water shaders there is sufficient GPU capacity left to run SGSS.

 

I can only therefore imagine its related to the loading of the textures in some way and (although you may have done this!)  I do suggest checking Texture Max Load and check textures aren't 32 bit.  If you are using REX reduce the water texture size as a test?