[+][SUG][PL] Anchor camera to a lemming

[WillLem]

This idea is courtesy of Armani, who has implemented it his custom NeoLemmix build.

Basically, right-clicking a lemming twice locks the camera to that lemming. The view then follows them until another is highlighted, or empty space is clicked. This is potentially super useful for watching replays back in Playback Mode.

Armani takes this a step further by also anchoring the Zoom function to the same lemming.

I'd like to add this to CE, but make it a hotkey (similar to the existing 'Highlight Lemming' hotkey) which toggles the anchor on and off, rather than 2 right-clicks.

We can decide later if clicking air should cancel the anchor. Air-clicks also cancel the replay and perform forwards frame steps; we probably shouldn't make it also do this third thing.

[Simon]

The main concern is that a moving focus stands to be irritating.

What are the use cases? Manually anchor camera in advance to the lemming that will receive the next 5 assignments? You need to know in advance what's going to happen. Yes, if you know that in advance, then you can use this to avoid manual scrolling and zooming. And zooming into the lemming (instead of into the cursor) is good then (it's the only way).

But why would such an interactive feature (manual anchoring to lemming) useful in televsion mode (that I never use)? It should be noninteractive, right? Or do you think darkshoxx would use it for the showcase? You may want a big fat arrow over the anchor, for the audience.

Ways to soothen the worry of the moving focus: Camera could jump according to some hysteresis, e.g., when anchor closer to camera's edge than 20 % of screen length, camera will jump into that direction by 50 % of screen length, putting the lemming back near the middle with view ahead. Unsure if the concentrated nastiness of huge jumps is any better than the smeared-out nastiness of a permanently moving screen. You can smoothen jumps by making the camera focus chase the anchor, not jump to the anchor, but still. And zooming into the lemming would be bad then, and we should continue to zoom into the cursor.

Ways to anticipate which lemming is important. Then you don't have to anchor manually. This ties into that other thread (I'll edit this) where I mull about painting markers over lemmings that are going to receive skills soon. Or anchor could switch to lemming that is going to receive the next skill half-time between any two assignments.

-- Simon

[Armani]

Most of what I implemented was the result of me experimenting and having fun rather than focusing on practical usefulness. I didn't expect any of it to be implemented into the official build so I just added anything that sounded cool.

That being said, I can still share how I personally use this specific feature. There are mainly two cases where I use this camera lock-on:

1) When I'm playing a level while someone is watching
I sometimes share my screen to playtest level packs for the author. When playing alone, I only need to focus on the key Lemmings myself so the camera lock isn't as necessary. But when there's a specific Lemming the author needs to focus on, locking the camera ensures they won't miss it.

2) When playing a level with multiple pairs of teleporters (+ large levels with tons of Lemmings)
I think showing a video is easier: https://youtu.be/W-eBc27MtGY?si=b11L5Sb0EOXLFqbf&t=4685
(This video showcases how some of the features work in-game. For the camera lock specifically, check out 1:26:35 or 1:26:50)