Performance issue full screen for India biome

[Langbart]

Issue

When playing a specific random map with the default settings applied in full screen everything felt very slow, like walking through mud. Performance was better in window mode.

to reproduce

• start the following map with the default settings and full screen

• Notice the extreme performance drop between full screen and window mode.
• See video below for more clarity. Watch the women walking to the meeting point. Everything is smooth in window mode, but slow in full screen mode.

​https://ttm.sh/wvr.mp4

observations

• After only reducing the materialmgr.quality value from 10 to 1 the performance is much better less bad.
• When only lowering the adaptivefps.session from 60 to 20 as mentioned in #6193 the slowdown is not noticeable between full screen and window mode.
• When only switching from OpenGL to OpenGL ARB the slowdown is not noticeable.

bisect

I am very confident that the change set [26859] is the cause of the problem.
Just to be clear, I also tested [26858], but the performance problem could not be observed in this big change set, it must be [26859].

reproducible

• The same map on A25 with the same game settings works normally, the problem must have been introduced after [25860].
• Even after increasing materialmgr.quality from 2 to 10 the performance was still better in A25 compared to the latest GIT version [27009]. This means that changing the default values with [26976] cannot be the sole reason, but that another change set must also have contributed to the issue.

[Vladislav Belov]

How does the performance change if slowly resize the window to the fullscreen size without enabling fullscreen?

[Langbart]

adding bisect number [26859].

[Langbart]

Replying to Vladislav Belov:

How does the performance change if slowly resize the window to the fullscreen size without enabling fullscreen?

I noticed the slowdown ~1550x1038, see video below for more clarity!

• ​https://ttm.sh/wvm.mp4

[Vladislav Belov]

Replying to Langbart:

adding bisect number [26859].

The commit code doesn't depend on resolution. If it's the reason it should behave the same for various resolutions.

Bisect might lead to a local slow down which was fixed afterwards.

[marder]

I can't reproduce. Both work ok for me.

[Langbart]

Replying to Vladislav Belov:

Replying to Langbart:

adding bisect number [26859].

The commit code doesn't depend on resolution. If it's the reason it should behave the same for various resolutions.

I undid all the code changes from [26859] and compiled, when I tested, the slowdown was not observed. I am very certain that the issue came with [26859].
PS: Added two notes to the ticket description regarding FPS and render backend under observations.

macOS

The ticket might be related to #6193 (1/Jun/21). See related IRC 0ad-dev discussion ​1/Jun/21 about #6193.