Polyobject portal discussion

[printz]

In the Eternity portal-fixes-2016 branch (not released on DRDTeam yet) there are polyobject-mounted wall portals. They create the effect of moving cabins/gondolas (they don't currently work as simple moving platforms because they need both floor and ceilings). Basically think of a polyobject inside which I carved a cabin.

They work for the most part, except that clipping is not checked for things standing inside the cabin but partially touching the outer walls. Also rotation is currently not supported.

Questions:
1) I implemented velocity conservation when projectiles pass through such portals. This means that if you're inside and fire some plasma, it will preserve the velocity of the car when exiting it. This may also subject it to Doom's velocity cap, unfortunately. But here's the problem: similar designs in Boom do not add the velocity to the projectile. If you're on a moving lift, you'll see the projectile going up or down when firing. If you're on a conveyor, you'll see the projectile trailing back instead of moving with you. Do you still think I should add the car velocity to the projectile velocity now, when using polyobject portals?

2) I just find this whole thing a very nice proof of concept, but clearly inferior to genuine dynamic sectors (whenever those get possible). There are too many things to be aware of, and quite some work to emulate realistic cars (consider all the work to conserve velocity, or the lack of collision of things with the outside world…

[Mordeth]

Do you still think I should add the car velocity to the projectile velocity now, when using polyobject portals?

My opinion: when inside the 'car', combat should look & feel the same as normal. So, if you fire plasma from inside the car to a target which is also inside the car, the plasma ought to behave the same as if you were in a normal sector. I guess that means adding velocity.

That does mean some weirdness when projectiles go from inside to outside the car, and vice versa; especially if said car can speed up or slow down. But I guess that's something the designer can take into account.

emulate realistic cars

If you manage rotating polyobject portals, you already have it. A player inside the car can then steer the movement of its own polyobject bubble. So you would 'only' need to take care of polyobject collision code.

[Graf Zahl]

Mordeth said:

My opinion: when inside the 'car', combat should look & feel the same as normal. So, if you fire plasma from inside the car to a target which is also inside the car, the plasma ought to behave the same as if you were in a normal sector. I guess that means adding velocity.

To be honest, I have my doubts that this plays well. It's already annoying when shooting the plasma gun on a moving lift.

[Da Werecat]

I think moving platforms affecting projectiles' velocity is gonna be weird. Similarly, shooting while moving on your own (running) should also affect it, but the game never behaved this way.

[Altazimuth]

Each solution has its caveats. Personally I'd vote to add velocity after it leaves/enters the ports so that a projectile's movement is linear, instead of a line that crooks after leaving/entering the moving polyobj sector. I feel like a non-linear moving of a projectile would be weird, stuff like rev rockets being a notable exception to my want for projectiles to travel in a line, of course predictable patterns are just a superset of lines. Either way, consistency of movement is key, in my opinion.