Linedef type 521

An example of using a linedef 521.

Linedef type 521, Carry Objects on Floor (Accelerative), is a type of linedef special which carries Objects on any tagged sector's floor without scrolling the floor flat. Unlike linedef type 520, the speed can be changed in an accelerative/decelerative fashion.

Setup

The direction of the control linedef determines the direction the Objects will be carried. The length of the linedef indicates the base carrying speed (32 fracunits of length equal one fracunit per tic), however the actual effective carrying speed is set differently as explained ahead.

On its own, this linedef will not carry Objects. Rather, the Objects will move whenever either the floor or ceiling of the control sector moves, which can done by using linedef executors. The actual carrying speed, in any given instant, is equal to the base speed × the distance the control sector has moved + the speed in the previous instant. In other words, every time the control sector's floor or ceiling rises, the carrier accelerates, and every time the floor or ceiling lowers, the carrier decelerates. If the floor and ceiling are returned to their original heights, the carrier will stop, and if they are lowered past this point, the carrier will accelerate in the reverse direction.

To keep things simple and easier to control, the best thing to do is just use a base speed of 1 fracunit per tic (by giving the control linedef a length of 32 fracunits), and control the carrying speed by moving the floor or ceiling of the control sector.

If used in conjunction with linedef type 401, the speed will instantly jump to a fixed value. If used in conjunction with linedef type 407, the speed will gradually increase or decrease.

If Flag [6] / Not Climbable is checked, the carrying effect is made exclusive – once an Object has been pushed by this effect, it cannot be pushed by any other pushing or carrying effect in the same tic. This is useful if the effect is applied to multiple adjacent sectors, since it would normally be applied twice when an Object crosses the border between two sectors with the effect. This flag should be checked when using the linedef special in conjunction with linedef type 64; otherwise the player will not stand still on the "moving sector".

Sample

Example file: ex_ld521_carryobjectsonfloor_accelerative.wad (MAP01)

How to use

You may load this file into your favorite map editor, such as Zone Builder. Select MAP01 as the map to load. You may also load this file in the game: Save ex_ld521_carryobjectsonfloor_accelerative.wad into the addons folder of your SRB2 directory. Start SRB2, go to the Addons menu, and then select ex_ld521_carryobjectsonfloor_accelerative.wad. Start the game in Single Player mode. Press the Console button (~), and type in the command MAP MAP01 to access the example map. When you load this file in the game, it replaces Greenflower Zone Act 1.