Editing Portal (section)

==== Example ====
You can use classic types 286-288 or UDMF [[Portal_Define]] in a similar way to the plane portals. But much easier is to use classic 450 or UDMF [[Line_Horizon]] on a sector's walls to copy its floor and ceiling rendering into infinity. No tag or args needed for this. Following is an example using 286-288.

Like the fixed plane portals, the front sector of the special line is used. The top plane uses the front sector ceiling (height, texture, scrolling, light) as its model, and the bottom plane uses the front sector floor (height, texture, scrolling, light) as its model. Example:

[[Image:Phorizon01.png]]

This map has a horizon portal applied to the ceiling and wall of the sector where the player starts. Both sectors have a floor height of 0, and a ceiling height of 72, but the floor texture in the dummy sector is set to a grass texture, and the ceiling texture is set to FSKY_1. This produces a field of grass which goes on into the horizon. If the camera moves up or down, the floor plane will appear to move along with it. If the ceiling plane had a regular texture on it, it would also move with the camera and appear to go off into the distance.

Note: If the camera ever travels below the floor height of a horizon portal, the bottom plane will appear to move in the opposite direction of the camera movement until the camera is once again above the floor height.