Fix chobby chili performance.

[GoogleFrog]

Chobby chili is a lot worse than old ZK chili without RTT.

[Licho1]

how can it be?

[GoogleFrog]

How how?

• Many years ago (perhaps around 2011 or so) jK released chili FTL,with many claimed performance improvements via render to texture and related things.
• ZK did not use FTL as it caused many graphical glitches and the RTT was bugged.
• ZK continued on its old chili version until the present day, features and bugfixes were added locally.
• Chobby was started by @gajop. He used the most recent chili version.
• Soon after I entered chobby development I disabled RTT because it was still bugged. We did some tested and found that the graphical glitches from FTL were gone.
• @lhog started making noises about UI performance and how something like RTT would be good to implement.
• Instead of writing a whole new UI framework from scratch, I merged the decade-old ZK chili with chobby chili.
• This merge took the bugfixes and features that ZK had needed over the years and merged it with the new drawing system and bugfixes of chobby.
• Upon doing this I discovered that chobby chili is far slower than ZK, at least with RTT disabled.

Chobby and ZK now use an identical version of chili. ZK has a duplicate chili framework that implements the old ZK version (enabled by default, as the performance of the merge is worse). Everything is unreleased at the moment.

In a standard test (200 selected patrolling Ronin zoomed on in Scorpio Battlefield) I found the following results:

• 6% CPU usage by chili with the old ZK version.
• 18% CPU usage by chili with the new merge.
• 2% CPU usage by chili with the new merge and RTT enabled.

The current hack in RTT chili is to turn RTT off for all scrollbars. This is sort of ok for ingame, because the only scrollbars (should) be found in the menu. Opening a menu with RTT enabled puts Chili at around 16% CPU.

I don't expect RTT to work for everyone so we need a compatibility fallback that has decent performance. It would be very encouraging for this fallback rendering mode to have as good performance as the old ZK chili.

[gajop]

Can you test Chili components separately? We might find the culprit easier that way (it might be component specific, e.g. editbox!).

[GoogleFrog]

The difference seems to draw lists. ZK chili uses draw lists. At some point new chili stopped using draw list and then became very confused as to how to translate properly to make draw lists draw at the right offset. Draw lists are completely broken.

[GoogleFrog]

Rendering to texture appears to be a lot slower than recreating a draw list. You can find a significant performance difference between the two chilies by doing the following:

• Select your commander.
• Click on the economy tab.
• Click on the special tab.
• Press Ctrl rapidly.

Old chili has climbing CPU usage in this situation, but new chili has a lot more CPU usage and the game noticeably freezes for a fraction of a second on each key press. The load is caused by adding/removing the hotkey from each button.

I fixed a bug that was causing chili to redraw the entirety of a tree when something in that tree changed, instead of only redrawing down one branch. Render to texture may be faster if it fully uses draw lists (instead of not using them at all).