continuity fixing (or: more realistic transfer between geo and battle)

[moriarty]

the recent idea of an EMP cannon got me thinking about continuity again. I've been thinking about this before, but now might be the right time to start implementing this...

here's the general idea: currently, the stuff you do to a UFO in the geoscape hardly affects the battlescape and vice versa.

1) if you hammer a medium scout with avalanche missiles until it crashes, you might end up with an undamaged battlescape UFO. if you wear down the same UFO with twin cannons, it might turn out completely destroyed.

2) if you board a landed supply ship, shoot all three power sources, grab the elerium, run out and leave, the UFO will take off and fly away.

3) if you enter an alien base, shoot all aliens but one, set off high explosives in every room (except the control room), leave the base and immediately come back, everything will be restored to its original state.

4) apparently, UFOs that are shot down drop down vertically, because they will be found in the middle of destructible terrain without any collateral damage.


so, I'd like to propose some additional mechanics:

1) damage transfer
battlescape UFOs should receive damage depending on the weapons that were used on them. the easiest way I can think of would be keeping track of the excess damage the UFO receives in shooting it down, and using additional "virtual explosions" before the start of the battle to simulate the effects (although we should make sure that those explosions don't damage the terrain - the damage was dealt before the crash, after all). this would even make low-power weapons like cannons or lasers more useful again, because they will cause less excess damage and have a higher chance of leaving UFOs intact. I'd like to see a battleship with a huge hole in the side where my fusion cannon ripped it open.

2) reverse damage transfer
if you cripple a landed UFO, its state should change from "landed" to "crashed". this would include destroying >50% of its power sources, destroying all navigation units, or destroying >25% of hull tiles.
(on the other hand, I believe the aliens should be able to repair hull damage, so perhaps it would even make sense to determine the cause of the crash in the geoscape when shooting it down... but that might be too complicated)

3) mission site continuity
any mission site (especially alien bases and xcom bases) should retain the damage they sustained, and this should have an effect on the geoscape gameplay. for xcom bases, perhaps damaged base modules could need repair time? alien base "farming" could be severely hindered by this, but on the other hand it would be easier to destroy heavily defended alien bases by "softening" them.

4) "path of destruction"
in crash sites, terrain damage should be included (remember apocalypse? the missions where you had to enter the UFO through sewer tunnels because the UFO was partially buried from the impact). this should be easy, I guess... simply determine a random direction and distance, and set off pre-battlescape explosions along the determined path. I'd love to see a building with a hole through it where a medium scout crashed through

[kharille]

This is good.  Gives me a reason to equip cannon on an avenger.  Good idea, even if its not something that would happen very often.

[Align]

What exactly causes a UFO to crash when we shoot it? It doesn't have wings or anything required to keep it aloft other than the power source. So all crashed UFOs should have exploded power sources, or at least all Navigators dead.

And what's the purpose of alien bases? They require risky supply missions constantly and don't send out any UFOs of their own. Can one even function without a commander and subordinates?

[moriarty]

What exactly causes a UFO to crash when we shoot it? It doesn't have wings or anything required to keep it aloft other than the power source. So all crashed UFOs should have exploded power sources, or at least all Navigators dead.

yes, I guess that is something that needs to be more clearly defined... I would guess that a UFO crashes if
a) a significant amount of power sources has been rendered inoperable (which shouldn't necessarily mean that they exploded, mind you... they could just be shut down without causing any further damage)
b) the navigation systems have been rendered inoperable (which again doesn't necessarily mean that they have been completely destroyed)
c) the hull has received substantial damage
d) the navigator has been killed

this, of course, is open for discussion. about "c)", I always assumed that while the power source generates the gravity waves that are used to propel the craft, the hull is used to funnel those energies. also, if the hull is breached in too many places, the craft will crash, because the biological entities inside will suffer from exposure to supersonic winds and a hypobaric environment, causing them to cease functioning as they should - a.k.a. the pilot will pass out.

I guess this calls for a more sophisticated damage model, right? perhaps the battlescape could serve as a "simulator" here. imagine this: every time a dogfight ensues, the game internally creates a mini-battlescape for each of the combatants involved, consisting of just the craft floating in the air. when the craft is hit in the dogfight, the incoming shot is created in the battlescape, causing damage to the craft. if the craft sustained appropriate damage in the mini-battlescape, the craft in the geoscape crashes (or is destroyed), and the craft from the mini-battlescape is then used for the crashsite - with all the damage it received. I don't know if that would need to be more simplified so as not to cause extreme lag, though...

And what's the purpose of alien bases? They require risky supply missions constantly and don't send out any UFOs of their own. Can one even function without a commander and subordinates?

that's more of a philosophical question... what do the aliens do in those bases? why, they scheme and plot and do alien things and ultimately generate activity points, which decrease your score. other than that, they sit there and wait to be attacked in order to serve as a mission for the player, duh

[Phezzan]

It's easy to use the overkill damage to change the likelihood that a power source is destroyed.

I've done it - and yes I keep cannons around for small UFOs.
I also randomized the amount of elerium in the power source slightly.

Please do some of this >random exterior damage< ... That would rock and allow interesting missions.

[Align]

I guess this calls for a more sophisticated damage model, right? perhaps the battlescape could serve as a "simulator" here. imagine this: every time a dogfight ensues, the game internally creates a mini-battlescape for each of the combatants involved, consisting of just the craft floating in the air. when the craft is hit in the dogfight, the incoming shot is created in the battlescape, causing damage to the craft. if the craft sustained appropriate damage in the mini-battlescape, the craft in the geoscape crashes (or is destroyed), and the craft from the mini-battlescape is then used for the crashsite - with all the damage it received. I don't know if that would need to be more simplified so as not to cause extreme lag, though...

I'm not so sure that'd be a good idea - the current interception mechanics are pretty well balanced except for the XCOM weapon ranges, and using a totally different mechanic like the battlescape could hurt that. It sounds like it'd allow interceptors to bring down terror ships in one lucky shot, what with their four adjacent cores blowing up all at once.
The game already feels pretty easy with all the bugs fixed..

[moriarty]

Actually the battleship is pretty immune, because the Power Sources are far enough away from each other - if one blows up, the others stay intact.

There's another thing that could be improved by a damage system like this: base defences. what always bugged me in the original is that you can skip all base defences until you reach fusion defences, then build four of those and you're safe. all weaker base defence are no use at all. even if you build two full rows of missile defences (that's 12 missile defences), it has no effect on gameplay whatsoever, because they will never be able to shoot a battleship down, and if the battleship goes through, the aliens will attack with a full crew.

if you use a more finely-tuned system, those defences at least have a chance of killing some aliens, so you won't have such a hard time defending your base.

[54x]

Actually the battleship is pretty immune, because the Power Sources are far enough away from each other - if one blows up, the others stay intact.

There's another thing that could be improved by a damage system like this: base defences. what always bugged me in the original is that you can skip all base defences until you reach fusion defences, then build four of those and you're safe. all weaker base defence are no use at all. even if you build two full rows of missile defences (that's 12 missile defences), it has no effect on gameplay whatsoever, because they will never be able to shoot a battleship down, and if the battleship goes through, the aliens will attack with a full crew.

if you use a more finely-tuned system, those defences at least have a chance of killing some aliens, so you won't have such a hard time defending your base.

Yeah, or we could even do a mod that allows other ships to attack your base if you're discovered relatively early in the invasion, and thus you'd have a chance of blowing a smaller ship out of the air if you hit its power core with say, a missile or laser defense.

[Align]

Base defence mechanics could definitively use some more granularity.

Actually the battleship is pretty immune, because the Power Sources are far enough away from each other - if one blows up, the others stay intact.

Yeah but even then you could get lucky and hit those with your first few shots. Or, conversely, it could take just way too long, chewing up four avengers because they got unlucky with their plasma spam.
I guess a bit of random chance isn't out of place in XCOM though.

So, since craft weapons would have to hit power sources or navigation equipment, would the basic cannon be powerful enough to produce those fancy melted walls you get after a blaster bomb in the battlescape (except max one square at a time) and other craft weapons just scale up and have a blast radius after that?
Cannon ammunition is armor-piercing so it could perhaps pass through the UFO walls without too much damage, but that still leaves the other weapons.

[moriarty]

unless we want to produce a whole lot of additional sprites, we'll have to stick with the "melted" UFO walls, I guess

for simplicity's sake I would simulate all weapons as explosions (with different blast radii, of course... laser and conventional cannon have a blast radius of 0-1, fusion cannon probably about 10-15...). that way even a cannon or laser cannon could have a chance of killing an alien that stands next to an outer wall.

[54x]

unless we want to produce a whole lot of additional sprites, we'll have to stick with the "melted" UFO walls, I guess

for simplicity's sake I would simulate all weapons as explosions (with different blast radii, of course... laser and conventional cannon have a blast radius of 0-1, fusion cannon probably about 10-15...). that way even a cannon or laser cannon could have a chance of killing an alien that stands next to an outer wall.

What you could do though is "melt walls" in straight lines for cannon fire, rather than have the huge breaches other weapons cause.

[MadMelvin]

alien base "farming" could be severely hindered by this

IMO that's a good thing... that always kinda bordered on being an exploit.

[Mr. Quiet]

For 3) mission site continuity suggestion. Wouldn't the supply ships refill the alien base back to full again? So you'd have to stop supply ships as well, or else you get the same amount of aliens(or more) and modules once again.

[moriarty]

of course, that's exactly what would happen. but if you go back to the alien base before another supply mission has taken place, you shouldn't find everything back to normal.

an alien base that has been attacked should also probably be resupplied with additional troops, making the next base attack harder. or it should be abandoned by the aliens altogether. anything but "everything continues on as if the player and his attack on the base never happened".

[Mr. Quiet]

Goody. These kind of small details and fixes are what would make the game perfect.