What makes menus (generally) so slow?

**StripTheSoul** · 02-02-2017, 01:30 AM #1

Heya guys!

This is not about a specific game or anything. I'm just curious about something I've observed a lot of times in emulators (at the moment mostly Citra but it was the same with Dolphin in earlier stages):
Some games have costly 3D graphics but are smoothly emulated while simple 2D graphics like menus and stuff are sometimes awfully slow, especially transitions between different menus.
Why is this? The 2D graphics themselves cannot be so taxing, can they? Is it just some kind of idle state that needs to be skipped for it to be faster?

**Helios** · (This post was last modified: 02-02-2017, 01:54 AM by Helios.)

In the case of MKWii its because the videos it's rendering absolutely destroy Dolphin.

**StripTheSoul** · 02-02-2017, 02:22 AM #3

Right, those make sense; but I'm talking about simple 2D menus without any videos or the like. Often, there's a rough slowdown when there's a transition from one menu to another... maybe some kind of transparency effect kicks in in that moment?

**Helios** · 02-02-2017, 02:35 AM #4

Can you give some games as examples?

mimimi · 02-02-2017, 03:36 AM #5

If it only happens the 1st time, it's obviously shader compilation. Transition from one menu to the other could be texture decoding though. You could try the GPU texture decoding PR for this:
https://github.com/dolphin-emu/dolphin/pull/4467
(don't forget to actually enable GPU texture decoding!)

Craftyawesome · 02-02-2017, 03:41 AM #6

I think it's because so many instructions fall back to interpreter. All of the FPRF instructions weren't JITed in 4.0

**Helios** · 02-02-2017, 04:44 AM #7

They're using at least 5.0

**StripTheSoul** · 02-02-2017, 05:37 AM #8

Hehe, thanks, guys, but I wasn't really asking for help regarding Dolphin. There's not a single game (I have) that doesn't run at full speed.
I was rather asking a general question regarding emulation. I'm sure I've seen this with Dolphin, too, but long ago.
Now it's rather newer emulators where you can still notice it. For example, the start screen of Rhythm Heaven Megamix... it's just some 2D stuff but it's very slow.
Last example I remember from Dolphin was the ingame-menu in Xenoblade Chronicles. The 3D graphics were super smooth, but the menus were rather slow. (although it's quite some time ago and I'm not completely sure if that was just due to custom textures).

**Helios** · 02-02-2017, 05:41 AM #9

It's likely custom textures without pre-loading, if that's the case.

**StripTheSoul** · (This post was last modified: 02-02-2017, 06:17 AM by StripTheSoul.)

Hmm, nevermind that example then... Don't you guys know what I'm talking about? Emulation slowing down especially when the image fades to black to go to another menu page? I thought this would annoy and puzzle everyone Big Grin

Unfortunately, I'm lacking good examples right now but I've had this so many times...