Sector_SetPlaneReflection

Warning: This feature does not work in ZDoom but in its OpenGL children ports.

159:Sector_SetPlaneReflection (tag, floor, ceiling)

• tag: Tag of affected sectors
• floor: Amount of reflectiveness of the floor. 0 means none and 255 means fully reflective.
• ceiling: Amount of reflectiveness of the ceiling. 0 means none and 255 means fully reflective.

Makes the tagged sector floors and/or ceilings reflective like mirrors. If used improperly this can reduce the frame rate quite drastically. You should keep the amount of reflective planes as small as possible.