Accelerative and Displacement Texture Scrolling: What are these?

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Fawfulfan

Fawfulfan

The Tortured Planet guy
I've been puzzled by Accelerative and Displacement Texture Scrolling since 1.09.4. First, what do they do that's different from regular texture scrolling? Second, when I try using them, they don't actually scroll the texture at all. How come?
 
I'm interested in this topic too. I'm trying to use a similar linedef, Linedef Type 531: Acc Scroll Floor Texture and Carry Objects, to create a "controllable" conveyor belt. Something like a conveyor belt that is stopped and the player pushes a button and the conveyor starts to work. I tried it using a trigger "Once" but nothing happens too.

(but I don't know if it's doable this way, though.)
 
It didn't work because Linedef Type 531 is a Texture Scrolling Linedef, not a Linedef Executor. Only Linedef Executors can be set up like that.

However, my question still remains: What is supposed to be different about Accelerative and Displacement Scrolling, and why don't the linedefs work?
 
Linedef Type 531 is a scrolling and pusher Linedef. Anyway, I understood. It means that triggers work only with linedef executors.

It'd be nice if we have a conveyor belt that can be activated, go onward and backward, and be stopped when it's triggered.
 
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Read up on TeamTNT's Boom documentation regarding the accelerative linedefs. Yes, they can be used to create a conveyor that speeds up, slows down, and can turn on and off.

I can't remember if an example was made, but you might want to check this folder (1.09.4 wads, you'll need to convert)
http://ssntails.sepwich.com/examples/
 
SSNTails said:
Read up on TeamTNT's Boom documentation
Click to expand...
I found the site, but unfortunately couldn't find the docs.

SSNTails said:
Yes, they can be used to create a conveyor that speeds up, slows down, and can turn on and off.
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This is truly good. But I never saw it working in a SRB2 level so I could open and learn how it works. :<


SSNTails said:
http://ssntails.sepwich.com/examples/
Click to expand...
Sorry, I didn't find any Acc or Disp Linedef here. I checked it considering 1.09.4 cfg (LD's 200-205, 214-218 and 245-249).

Thank you for replying. :>
 
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These specials work by checking the floor and ceiling heights of the control sector. If floor height + ceiling height is different than it was in the previous tic, the scroller will move forward or backward accordingly, depending if the value is positive or negative.

EDIT: If either the floor or ceiling height of the control sector are changed, the scroller will move by (new floor + new ceiling) - (old floor + old ceiling), provided it's positive. If the value is negative, nothing will occur.

Since the operation performed is floor + ceiling, you need only to move one of the planes to achieve movement. If you move both of them simultaneously, the result should be double the speed.

Accelerative version adds the result to the existing value instead, so it will maintain its speed when the control sector is still, and speed up/slow down when it's moved.

In your case, if you want to make a button that activates a conveyor belt, try using an Accelerative line, and making the button's linedef executor change the height of either the floor or the ceiling of the control sector once.

I haven't tested this at all, I just surmised it from looking at the source.
 
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So I tried this out but couldn't seem to get it to work. Whenever I use an accelerative or displacement scroller, the textures aren't scrolled, and they don't even start when I use a linedef executor to modify ceiling or floor height. I am either too stupid to understand this (which is likely), or it doesn't work.
 
Negative values don't seem to work, and the floor height is completely disregarded. So you would need to work around this by setting up a second scroller that goes into the opposite direction.

EDIT: Also, I solved my problem. I forgot to apply a second effect to my button. Kinda stupid, huh?
 
The displacement scrollers seem to set the position of the scroller rather than the speed. That means that if you put a ceiling height of 20, the scroller will move 20 fracunits at once and then stop again. For some reason, the texture itself is not actually scrolled, through, it only pushes the objects.

EDIT: Umm yeah, I just learned that "displacement" does not mean the opposite of "accelerative", but rather "distance". Thus, this post is pretty much common sense.
 
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WOOOOOOOOOOOOOOOOOOOOOOOTTT!!! Worked!

Required 8 control sectors: 2 per switch, 2 for conveyor (one for each direction)

Each > and < switch triggers 2 control sectors, turning off a direction and turning on opposite direction. The central switch triggers 2 control sectors that turn off both directions.

Have fun: http://ezerarch.uuuq.com/files/Sample-controlableconveyorbelt.zip

EDIT:

Seems I discovered a bug: while the conveyor belt is moving, player keeps in walking state, rarely is in standing state, when this happens, the player seems to move slower than the conveyor itself.

EDIT2:

If the player stands on a pushable object, conveyor belt can't carry the player.
 
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I just used Linedef Type 435 on a regular conveyor belt and it seems to mess up the scroll effect. The texture is scrolled slower than the object is carried.
 
Ezer.Arch said:
EDIT:

Seems I discovered a bug: while the conveyor belt is moving, player keeps in walking state, rarely is in standing state, when this happens, the player seems to move slower than the conveyor itself.
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That's not exclusive to Acc/Disp Scrollers; regular conveyor belts do that too.
 
There's a "Conveyor Belt" sector type for just that reason, y'know.
 
I should've said that "bug" happens even with Sector Type 1024 - Conveyor Belt.

1024k.png
 
I guess Inuyasha was referring to fawfulfan. This bug happens to normal conveyor belts when you don't use the sector type.
 
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