'ceilingterrain' is needed because the top of 3D-floors refers to the model sector's ceiling, so in order to give a 3D floor a terrain it must be assignable to the sector's ceiling.
Note that although it is basically the same property, its actual function bears no relevance to its use in Eternity.
Issues with the old code:
* when calculating friction for a 3D-floor - swimmable or not - the 3D floor's top texture must be used. The previous version always checked the sector's floor texture, even though the top might as well come from the sector's ceiling.
* 3D floors never checked for the SECF_FRICTION flag at all. According to Boom specs, sector-based friction must be ignored if this is the case.
* Terrain based friction had a higher priority than the sector's own value.
Changed the rules as follows:
* if the sector's SECF_FRICTION flag is set (i.e. something explicitly changed the sector's friction), this value is used regardless of terrain settings.
* if this flag is not set, the terrain's friction is used, if defined, using the proper plane for 3D-floors.
* otherwise the default is used.
- Disconnect scripts were previously run at some point after the player
left. Now they are run immediately before destroying the player. Since
the player hasn't actually been destroyed yet, the player also gets to
be the script's activator. This gives you a chance to scrape whatever data
you want from the player before they're history. Note that if you do
anything to make the script wait, the script's activator will become the
world, as it was before.
- The old algorithm is something I threw together that produced decent,
but not spectacular results since it had a tendency to waste space by
forcing everything onto "shelves".
The new packer is the Skyline-MinWaste-WasteMap-BestFirstFit algorithm
described by Jukka Jylanki in his paper *A Thousand Ways to Pack the Bin - A
Practical Approach to Two-Dimensional Rectangle Bin Packing*, which can
currently be read at http://clb.demon.fi/files/RectangleBinPack.pdf
This is minus the optimization to rotate rectangles to make better fits.
The old method had a problem with missing order numbers and aborted the level load and made many assumptions that no longer apply with BSP based polyobject rendering.
- major overhaul of the static sector damage system:
* consolidated special based damage, Sector_SetDamage and UDMF properties into one set of damage properties. The parallel handling that could lead to double damage infliction was removed. This also means that damage through sector specials can be retroactively changed through Sector_SetDamage.
* all special cases were turned into flags. The new system can switch between Strife's delayed damage and regular damage, and it can also set whether terrain splashes are used or not. It also has access to the special properties of the end-level type (i.e. switching off god mode and ending the level.)
* the damage related flags are accessible through Sector_ChangeFlags, not the damage functions themselves.
Since Eternity got this it's a good candidate for a potential Super-Boom standard, and it's also useful for silencing a sector temporarily without removing the sound sequence.
- moved sector secret information from sector_t::special and secretsector to two flag bits in sector_t::Flags.
This is to get rid of the bit masking madness in the floor/ceiling thinkers which need to preserve this bit when they change a sector's type.
