====== Build stairs (XG class) ======

<code>Class = build_stairs
</code>
Forms incremental structures (stairs) from one or more series of [[plane]]s. A sound can be played at the beginning of the stair building, before starting to move each step, while a step is moving and when a step reaches its destination.


===== Parameters =====


^ Prm^ Name^ Type^ Meaning |
| Ip0Ip1| Target RefTarget Num| [[lpref]][[lprefd]]| Reference to planes where stair building will begin. |
| Ip2| Spread Texture| integer| If true (non-zero), stair building will only spread to planes with the same texture as the first plane. |
| Ip3| Spread Build| integer| If true (non-zero), stair building spreads to all adjoining sectors that have a line facing the current sector (spread build). If false (zero), stair building only spreads over the line that is facing the current sector and has the lowest index number. |
| Ip4| Start Sound| [[soundid]]| Name of the sound to play when the building begins. |
| Ip5| Step Start Sound| [[soundid]]| Name of the sound to play when a step starts to move. |
| Ip6| Step End Sound| [[soundid]]| Name of the sound to play when a step reaches its destination height. |
| Ip7| Step Move Sound| [[soundid]]| Name of the sound to play while a step is moving. Each step will play its own sound! |
| Fp0| | float| Build speed (units per tic). The first step will move to its destination height using this speed. A speed of 2 would move the step 70 units per second. |
| Fp1| | float| Step height. Both positive and negative values are accepted. This is the height difference between two consecutive steps. |
| Fp2| | float| Time to wait before starting to move the first step, in seconds. |
| Fp3| | float| Time to wait between steps, in seconds. |
| Fp4| | float| Move sound minimum interval, in seconds. The step move sound is played at random intervals, this (Fp4) setting the minimum and Fp5 setting the maximum. |
| Fp5| | float| Move sound maximum interval, in seconds. |
| Fp6| | float| Build speed delta per step. The step build speed will be modified with this value before starting to move each step (except the first one). Both positive and negative values are accepted. |


===== Examples =====
  
  Line Type {
    ID = 5020
    Flags = player_cross
    Flags2 = when_act | any
    Class = build_stairs
    Type = timed_off
    Count = 1;
    Target Ref = "lpref_line_tagged_ceilings";
    Spread Texture = 1;
    Spread Build = 1;
    Start Sound = "swtchn";
    Step Start Sound = "pstart";
    Step End Sound = "pstop";
    Step Move Sound = "stnmov";
    Fp0 = 1;
    Fp1 = -24;
    Fp2 = 1;
    Fp3 = 0.5;
    Fp4 = 0.25;
    Fp5 = 0.25;
    Fp6 = 0.5;
  }