More info about Vanilla Events and Autoscroll

[Emral]

Hey.
You might've seen my video about autoscrolling.

In short I fell down a rabbit hole and learned some stuff that for 15 years it seems nobody bothered to really look into?
This thread is DLC for that video. Didn't wanna record more. So I'll bust some myths.

First off: There is a small lie in the video to make the explanation easier. You don't HAVE to use Level - Start to set the section bounds. You can use any event that is not an Autostart Event. Autostart Events bug out in funny ways. Try it for a laugh but not for anything serious.

The basics:
- Autoscroll Speed setting needs to be in the event with the number of the section you're setting the speed of. I call this the event index bug.
- Autoscroll speed setting does not need to be in the same event as setting the section's boundary. In fact, I encourage you to put them into different events.
- The section boundary should be set by an event to the region where the autoscroll begins. The default section boundary as seen in the editor should be the entire section.

Claim 1: It is not possible to have a checkpoint in an autoscroll section using 1.3 autoscroll.
Yes it is possible. It's pretty straightforward if you understand the basics of how this all works. The setup is as follows:
1. Set autoscroll speed in the event with the correct index [Level - Start for Section 0, Pswitch - Start for Section 1 etc]
2. Create 2 more events. One sets the screen bounds to the start area, one sets them to the checkpoint area.
3. Place an invisible trigger for the start area on the start point, place one to trigger the checkpoint area event at where the player spawns from the checkpoint.
4. Make the event for the start area hide the layer that the checkpoint area trigger is on.
There you go.

Claim 2: It's not possible to change the speed of autoscroll at runtime without the use of lunalua.
Correct. This is because of the event index bug. So you need to use lua for this. Not necessarily lua autoscroll, as you can also manipulate the autoscroll speed of the event and then trigger the event. Or find the memory offset where section autoscroll speed is stored. Or you can make copies of your scrolling section and fake it. There are some options to get around this.

Claim 3: It is not possible to move the section boundaries of a section you are not in. This glitches out the camera.
Yes and no. It glitches out the camera if two conditions are met:
1. The section you're changing the boundary of is of a HIGHER NUMBER than the one you're in
2. You are not setting the boundary of the section the player is in.
So if you are setting section 1's boundary from section 0, you get that glitch. If you set it from section 2, and you ALSO set section 2's boundary (even if it's the same boundary as it already is) in the same event, then there is no issue. You can use this knowledge to reset autoscroll section scroll position from a different section. Or define different start points for an autoscroll. Enjoy. This has been in the game for 15 years.

I'll add to this thread if I find anything else fun.

Again you can also just use lua for all of this to make it a lot easier but my fellow vanillaheads will appreciate this knowledge I bet.