MAP21: Shaman's Device (Community Chest 4)

MAP21: Shaman's Device is the twenty-first level of Community Chest 4. It was designed by Chris Kassap (lupinx-Kassman) and uses a MIDI of "Against Nirvana" from .

Secrets

 * 1) In the area with the staircase past the crushers, head down the steps to the lighter gray floor. Inspect this area for a lever switch, then head back up to find a chainsaw in an open secret. (sector 433)
 * 2) In the northern area with the walkways, head for the staircase leading down and follow the trail of health bonuses to a secret with medikits and a megaarmor. (sector 794)
 * 3) Just before the hall with spikes, a wall opens up behind you with some monsters inside. There is a blocked-off passage to the north. To reach it, head for the two steps, but be careful as there are crushers already active on these steps. Climb them and jump out of the ledge to hear a lift lowering, then quickly head through the passage to obtain a plasma gun and an energy cell pack. (sector 1352)
 * 4) On the walkway's at the southern part of the main area, use the lift to go upwards and then jump to the red-bordered platforms. Manuever to the teleporter and take it to appear near a switch. If you look to the north, you will find a section of walkway with a teleporter that you can jump to. Take the teleporter and you will be able to obtain energy cells, a soul sphere, and a megaarmor. (sector 718)

Bugs
A medikit (Thing 1327) in the south has no flags set for any of the three difficulty classes, so it does not actually appear in the level.

Current records
The records for this map at the Doomed Speed Demos Archive are:

Miscellaneous demos
''This information was last verified in its entirety on January 23, 2018.

Deathmatch
This level contains its own, separate deathmatch arena based on Kassap's MAP25: Kass duel tower from 32in24 III: DUEL CORE. The most notable changes are that the exit portal has been replaced with a simple switch; the exit sign is moved from the floor to the ceiling and has had its triggers removed, meaning it does not block the exit-opening trigger anymore; and the trigger to open the exit is no longer untagged. The last two of these changes allow the level to be exited outside of ZDoom. Two start locations that originally spawned players without a shotgun unlike the others are now given shotguns for better balance. This version also removes several unnecessary sectors that were left over from raising sectors to the ceiling to create zero-height sectors rather than deleting them. It is otherwise identical to the original map.

Things
This level contains the following numbers of things per skill level:

Technical information
Floating See-through Platforms

At several parts of this map, floating see-through platforms, with their edges marked by red lines of light, can be seen. Some can even stepped on.

These sectors are created conventionally and have their floors raised to the required height. All sidedefs of the sector are given specialised middle textures, which are transparent images of the lines of light. The middle texture is offset so that its top edge aligns exactly with the floor of the sector. Next, the sector is subject to a "create fake ceiling and floor" action (Boom action 242), with the control sector's ceiling height and floor height exactly the same as the surrounding area. Thus, while the "actual" floor height remains exactly the same, action 242 draws a fake ceiling and floor similar to that of the surrounding area, causing the lower texture of the sector not to be drawn. The sector thus blends in with the surrounding area. All that is left are the middle textures, creating a floating see-through platform that can be stepped on.

For some of these floating objects that never need to be stepped on at all, all that has been done is to place linedefs where the lines of light need to be, give both sidedefs the specialised middle texture, and offset the texture to the appropriate point in midair.

The outline of some of these platforms is much brighter than the surroundings. This is done giving the platforms and a surrounding sector light levels of 255. However, the ceiling and floor of the platforms and the surrounding sector are set to the light level of the surrounding area by use of Boom actions 261 and 213 respectively. Hence, the only surfaces affected by the light level of 255 are the middle textures representing the outline of the platforms.

Of note is that this method works only where the floating platform never needs to be both stepped on and crossed under (while the visual element of the platform stays still). To do both requires the use of a self-referencing sector to create an invisible platform that raises when the player proceeds to cross it, and lowers when the player needs to cross under it.