Physics...

by Dr_Evil1 on 09/09/2007 14:27, 127 messages, last message: 04/30/2008 03:02, 94897 views, last view: 05/18/2024 21:16

Out of interest, how advanced is the physics in Sauer? The only notable useage I see in-game is the GL rebound of walls, and a slower movement time whilst in water, (both player and grenades).

Increasingly, physics is becoming a parallel with graphics in importance in new gaming titles. Half Life 2 comes instantly to mind.

If the physics are basic, if they were to be improved levels with physobjects could become a reality. New gamemodes, mods and SP missions could become a reality. Graphicly, Sauerbraten is probably the best open source game out there, especialy the water :-).

Personaly as a BIG HL2 and GMOD player, the possible inclusion of a physics engine per-say would increase the quality of gameplay dramaticaly.

Thoughts? -- Dr_evil

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#1: ..

by rhys424 on 09/09/2007 16:28

How would it increase the quality of gameplay? Sauer\'s gameplay isn\'t structured that way. Something like a gravity gun would not work well in Sauer.

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#2: Re: ..

by w4 ¿?¿?¿ on 09/09/2007 17:39, refers to #1

I really just want some inertia.



I think the portal gun would be a much better choice then the gravity gun. Even though Portal is a puzzle game, putting a portal gun into sauer would be crazy, especially multiplayer.

I dont think sauerbraten has enough physics and camera/effects tools to really get this to work correctly.

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#3: ..

by Acord on 09/09/2007 19:00

Physics may be a sticking point - does Sauer REALLY need physics? There are no vehicles, few extraneous objects, and the pinball physics that exist now do the job.

In my opinion, physics has only been used in games where the gameplay must be changed up in order to keep the player interested. Newer games are continuously falling prey to this. Ever notice that when something that is actually *exciting* occurs in HL2 that there's really no need of the physics? For example, running around and killing all the zombies(my favorite part, naturally) was an adrenaline rush. There were tons of them, they continually respawned behind you, it was dark and there were no traps. Just "get to the church".

The driving part? BORING. Same with the boat. BORING. Lets see... driving along... oh look, it's some monsters who have no hope at all of stopping my car. *squish*. Oh look, more soldiers. It's a good thing they don't use grenades. Oops, I accidentally knocked over a pier with a tiny fiberglass fan boat and everyone died. Oh, I have to hit a switch here, so I guess I'll get out and shoot some people in this wide-open boring ass terrain.

And the rest? Oh look, I can pick up this sawblade and use it as a weapon! Wait, wouldn't it have made more sense to have an actual weapon model instead of a "physics gun"? Oh well, it's just gonna float there. Oh, that looks like a trap I can use! I sure wouldn't stand under that thing, but it sure is a good thing that the AI is so stupid! Kinda wierd considering how it was a big deal in it's predecessor. Oh well!

So no. The physics aren't really needed at all. It's overkill.

Now, you want to see a game that used physics well? Mercenaries really used the physics. I can't tell you how many things I swatted out of the air with a car attached to a winch on a helicopter. Missiles, helis, and if you were really good, you could whip that sucker around like a ball and chain and send a van into anything at 60MPH.

Or Halo. Everyone abused the physics in Halo. Let's see if we can frag the warthog into that little flying bastard up there. Car doesn't fit? It's okay, I've got a rocket! We'll make it fit! And everyone's favorite, let's blow the warthog clean over the island.

But the funny thing in both cases is that the physics was just there, and not a main focus. That's what made mis-using it fun. Being forced to use the physics is not fun.

So, sauer probably *could* benefit from physics, but not significantly enough to make it a priority. Having a little is fine, as long as they aren't to realistic, but having a lot is pointless. The only thing I ever saw that made good use of HL2 physics was Gary's mod.

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#4: ...

by Dr_Evil1 on 09/09/2007 19:05

If you have ever played a game like HL2 DM or a mod like SourceForts you can definately see the gaming benifits of physics. Not only can you do the standard chucking physobjects at people, but you can create forts, baricade walls, make cover, create sniping spots and play around with the whole gaming dynamic. As soon as basic constraints are engineered, (rope, hovering, thrust, axis, welding) a whole plethora of gaming posibilities becomes open to you.

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#5: hmm

by ATIRULE on 09/09/2007 19:11

Acord is allmost right But this is something that needs to be put in place. and that will open the doors for other things and who knows if sauer had some halfway good physics it Might attract some more attention by Moders
Just because the dev's wont give us Sauer Raceing dont mean the someone like quin :) won't =}

Btw Even if something Dont Fit With Sauer Don't mean it should be Shot Down
Ps physics would be usefull in the rpg :0

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#6: ...

by Dr_Evil1 on 09/09/2007 19:26

Personaly, I was thinking that the physics could be used to make the single player \'campain\' more interesting, as opposed to a strict multiplayer use. While I do see Acord\'s points, I think that the inclusion of a physics engine could open up some of the features that many sauer players have been asking for since the Cube days (man, good times!). Vehicles and destructible objects (Que the exploding barrel :-), both physics dependant game entities can definately add to the game experiance. For instance, in River_c, a jeep or \'Warthog\" like vehicle would be great fun blasting all over the place with jumps and possable a mounted MG turret.

After 20 seconds of searching on google I found a opensource physics engine with advanced object colision and joints, way above the kind of physics I am suggesting could be implimented into Sauerbraten.

Thoughts? Suggestions?

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#7: Re: ...

by Aardappel_ on 09/09/2007 20:06, refers to #6

there are many sides to possibly enhanced physics in sauer.

First, sauers current collision works directly from octree data, which is much more neat than having it work on generic meshes, because it gives us spatial information a mesh doesn't have.

What a game like HL2 has over sauer is rigid body dynamics instead of sauer's particle dynamics. Ideally, a new dynamics system would use sauers existing octree based collision.

Now we could write our own rigid body dynamics, and I wouldn't mind because it be a fun project, but its also a LOT of work and rather complex to get right.

We could link in an existing one, but most existing libraries work with meshes, and handing such a library a mesh version of a sauer map would be horribly inefficient. It is like making the information more complex and then letting the physics library al reconstruct it.

Couple that with the fact that the physics library situation is rather a mess. Just because some open source library says it implements rigid body dynamics and it can throw some cubes around doesn't mean its usable, doing the same for a sauer world is a whole different ballgame. Frankly, all libraries out there are unstable (as in, physics integration, not buggyness) and inefficient, the best ones (havok, ageia) are not usable because they are not on every platform / not usuable for open source.

So yeah, it would be cute to have, but the reality is messy. We don't like messy. We'll implement something non-messy when that becomes possible :)

Meanwhile, REALLY think what you'd want this to do for gameplay in a game like sauer. If you think a few tumbling crates adds gameplay, you need to think a lot harder.

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#8: ...

by Dr_Evil1 on 09/09/2007 20:33

Lol, I was thinking of something a bit more complex than falling crates, but I see your point.

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#9: ..

by Acord on 09/09/2007 21:48

Physics will not automatically result in an improved game, or even a good game. In fact, it seems to take away focus from creating good gameplay.

Including physics at THE END of a project's lifecycle seems to be the way to go in FPS games. This way, the core gameplay has already been designed without physics in mind, and it's been more carefully constructed because of it. The physics are an added bonus, which can not detract from gameplay at that point. Good examples are the original Half-Life, Halo, Chronicles of Riddick, Mercenaries, and GOW, all excellent shooters that would hardly have suffered if you yanked out the physics.

Bad examples are later levels in HL2(why switch from shooter to sandbox halfway through? Stupid! Especially in a linear storyline!), Gunwitch, Second Sight(Even the guys who made Timesplitters screw up), and Destroy all humans(made by the same folks who made Mercenaries).

If physics is included in Sauer, it does open up some new gameplay possibilities, but it could also create a lot of new issues, issues which even professional developers can't find a way around. The temptation to saturate the world with it so it's no longer fun seems to be too great for even companies like Valve. If I wanted realism I wouldn't play video games.

Also, remember that the more complicated you make something, the greater the chances are of introducing errors into it, and the longer it will take to create content such as levels. In the final analysis, it seems that it's better to spend that extra time making the level balanced and fun and involving. The problem with creating a sandbox is that there has to be lots of room to play, which actually runs counter to good level design and leads to very bland wide-open levels.

I'm not saying that it wouldn't be good to have at some point, but I am saying that it isn't really necessary for a fun game, and that it will create more pitfalls for designers than it will create opportunities.

Now, there are games where physics are needed. But they are not actually necessary in FPS games. Racing games? They definitely need great physics. Pure sandbox games? Absolutely.

And another point: Great physics in a game don't always mean REAL physics. Ever play RUSH? Still one of the all time best racing games EVER. Also had some of the most unrealistic physics seen outside of cartoons, but it worked. Same with Halo. Mario Kart? I think I hear some physicists spitting blood.

There are so many things that are more important for the devs to work on than physics. Stability, modability, ease of use, better collision detection, better demo abilities, multi-player co-op(one of the most asked for things ever), the list goes on and on. Physics should be at the bottom of that list.

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#10: ..

by Acord on 09/09/2007 22:07

Also, let's not forget to mention all the extra values that have to be transmitted over the network in a multiplayer game with physobjects.

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#11: ..

by Captain_Ahab on 09/09/2007 23:27

it already has physics....things that go up fall back down. That's really good enough.

Just let it apply to config-listed map models for pushing crates and stuff around. For non living entities, ( like crates ), just align their local z axis to the normal of the ground its sitting on and let it slide like a skiing ogro if need be.

Vehicles can just be mapmodel objects that have players in its 'inventory' but let the player control the object whose inventory he is in.

I feel there are other more important things to deal with for (RPG) gameplay first.

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#12: ..

by w4 ¿?¿?¿ on 09/10/2007 01:59

sauerbraten doesnt need great physics because its a deathmatch game without vehicles. games lake crysis or BFBC actually rely heavily on their physics for the gameplay.


And please no ragdoll physics ever

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#13: ..

by Drakas on 09/10/2007 09:14

Basic mechanics are enough for today :P

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#14: ..

by AnimateDream on 09/11/2007 02:43

The physics.cpp seems needlessly complicated.
Wouldn't it be simpler to add up all of the vector forces present and get one vector force, multiply it by an inertia value to get one vector acceleration, and just use that to calculate velocity. I've looked over the code briefly and I can't understand what's going on most of the time, or why velocity when falling is calculated by a the time spent in the air times gravity when you could just make the gravity a force instead of an arbitrary velocity constant. I can only guess some of this mess is designed to make client side ghosting easier, but I want to expand the physics without getting a headache. Is there better documentation anywhere or am I just stuck with the few comments in physics.cpp?

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#15: hmm

by hsfjdldconorkirkdfhdfhsdf on 09/11/2007 03:04

I have no idea about physics.cpp but I know that the physics are done in discrete steps at a fixed fps :D

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#16: ..

by PudMoZ on 09/15/2007 02:30

I'm pretty sure that physics isn't exactly the same as collision detection. Sure, collision detection is part of physics, but it's not all of it.

Take Marathon, for example, that game probably had the worst collision detection of any 3d game: Objects only had a "radius" and when you got too close to them you could only move backwards, not left or right, which could sometimes become really annoying.

But, it had quite good (for its time, maybe even now?) physics for the weapons: rockets would have more kick than pistols, rocket explosions would send you flying not only back but up (provided it exploded below you), all the weapons had some degree of inaccuracy (there was no weapon that could fire dead center... of course, there was no sniper weapon or scopes of any kind), there was inertia... It at least had "plausible" physics.

I'm not sure but it seems like in Sauer, the only thing weapons do is knock back enemies and you a fixed amount... and the only weapons that aren't perfectly accurate are the grenade launcher and machine gun. Maybe this is just one of those quirks of being a "doom/quake-style" fps...? Is this intentional? I mean, it's neat and all, but when I try and get my friends to play Sauer they're like "zomg the weapons are all the sameZ!11"

Sorry if that turned into a bit of a rant but I hope you can see what I'm saying. :P

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#17: Re: ..

by Quin on 09/15/2007 03:58, refers to #16

Yeah, but that's both Sauerbraten's strength and weakness.

I personally get bored of playing after a while myself, but then again, I enjoy coding a feature more than I do using it.

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#18: Re: ..

by Aardappel_ on 09/15/2007 22:09, refers to #16

physics generally is the sum of two components: collision and dynamics.

dynamics is where game engines differ the most, sauerbraten (and most older quake engines etc) implements whats known as "particle dynamics", where the elements it moves do not rotate (the word "particle" here doesn't relate to particle graphics).

Then HL2, far cry etc added "rigid body dynamics", which adds rotation to the picture. This allows for boxes to tumble rather than just merely slide around. Adding rotation seems like a small step, but it is rather complicated, a rigid body dynamics system can easily be 10x as complex (and slow) in code as a particle dynamics system. Part of that may be increased complexity in collision as well, as rotating objects introduce whole new ways of getting things stuck, so more elaborate sliding/intersection methods are required.

The next step is soft-body physics, where stuff deforms under pressure. While not too difficult for some specialized objects, it will be a while before the entire physics of the world in a game will use this :)

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#19: Re: ..

by SanHolo on 09/15/2007 22:13, refers to #18

Hehe, Aard, this sounds as if you're really looking forward to code all that stuff. ;-)

Cube 3... =D =D

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#20: Re: ..

by SheeEttin on 09/16/2007 03:43, refers to #18

I'm intrigued by the prospect of really powerful chips that simulate discrete particles of matter.

Not like in real life, but maybe fist-sized chunks of stuff. Each material having a certain weight, strength, resistance to being broken (like a stack of magnets, when hit, some stick together... know what I mean?).

It's really interesting, but it's nowhere near feasible.

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