The games of today are shipping more and more frequently with support for physics-based effects and gameplay: puzzles, rag-doll corpses and simple projectiles are some of the common examples. Most of these elements are fairly simple: a few rag-dolls visible at once, perhaps, or a physics puzzle with only a handful of moving parts. There's a good reason for this. The simulation involves rather a lot of math, and thus takes a lot of CPU power which could otherwise be used to drive gameplay, networking, input, or any of the myriad other tasks a modern game must implement.

There's another component of many games that used to be rather taxing on computing power - that of rendering 3D graphics to be shown on-screen. As processors failed to keep pace with the increasingly difficult task of rendering the virtual worlds in which we play, a new breed of hardware component rose to prominence in gamers' PCs - the 3D graphics accelerator. Ageia Technologies is hoping to do for physics what the 3Dfx's Voodoo chip did for 3D graphics: bring dedicated hardware acceleration into the mainstream.

In 2006, they launched the PhysX board, which provides hardware dedicated to the acceleration of physics calculations. But, consumer adoption of the card has not exactly been stellar. Most games supporting the card do not require it, as not to alienate customers without, and thus can only use the card to produce effects which don't influence gameplay. As few games require the card to enjoy the gameplay, there's little motivation for gamers to dig out their wallets -- and in the meanwhile, Ageia's competitors are hard at work. So, what's a hardware vendor to do?

The answer? Commission Warmonger, Operation: Downtown Destruction a freely-downloadable first-person shooter with a decidedly physical bent. Many shooter games now allow weapons fire to move or damage objects within the world - Warmonger allows a player the creative freedom to redesign the map with a few well-placed rocket blasts.

In short, the biggest advance that Warmonger brings is the ability to blow holes in walls (and ceilings, and floors…) with the appropriate arsenal. The PhysX card - which is, of course, a requirement to play - allows for a few other features as well including: realistic smoke affected by passing people and projectiles; cloth that can be torn or rent; and a ton (or several) of realistic debris are just some of the highlights. But the biggest change in gameplay stems from the fact that almost everything can be destructible.

The amount of destruction allowed does vary by map. An earlier internal build allowed absolutely everything to be destroyed, which led to the play arena becoming an empty plain within a few minutes of concerted rocket-launching and grenade-lobbing effort. So, not everything can be demolished. But in most cases, an inconvenient wall or a sniper's nest can be taken out with explosives; a wooden face breached with an automatic weapon or similar; and less-substantial barriers such as cloth taken out with a pistol.

One of the NetDevil's goals was to solve the 'titanium fence' problem - the immersion-breaking reality of many games that a small chain-link fence is often one of the best defenses against high explosives that money can buy. And they have.

Treating map elements as disposable bits of scenery brings about a slight change to the FPS player's mindset. Knowing the precise details of the map layout is slightly less important (after all, it could change at any moment - or you could simply change it yourself), because situational awareness is now key. Sniping in a dark corner becomes less attractive when a casually aimed rocket can take out the walls defending you. A 'safe' corridor is only safe so long as no-one takes it upon themselves to improve the ventilation. In the long run, learning to react to the changes in the environment around them must become a key skill for Warmonger players.

Three game modes are supported: Attack/Defend, which could be best summed up as 'one way capture-the-flag'; Team Deathmatch; and Capture and Hold, which involves seizing then defending specific areas of territory. The game is obviously designed for multiplayer carnage, but bots are available should a lack of sufficient humans to play against be an issue.

The game ships with five maps; each offering a different flavor of gameplay. For example, a subway station map showcases physics-based eye-candy, including realistic smoke and showers of ceramic tile chips, whilst a map set in a parking garage demonstrates the additional gameplay options made available to the resourceful player with a rocket launcher.

So... how does it play? Perhaps a few representative snippets are the best way to convey the rather unique feel of this game…

Being chased up a flight of wooden stairs in an abandoned building then cutting off my pursuers by destroying the stairs behind me…

Running into a brick wall... pausing for a second... then backing up (wall fragments hurt!) and whipping out a rocket launcher to "forge" my path.

Peeking out from behind a wall to take out a group of enemies with a grenade... and watching my cover be blown to pieces scant seconds before my targets follow suit.

Crouching with a mini-gun and energy shield, ripping a cloth banner to shreds, and then taking down my opponent.

Warmonger is... a little different.

The game has a post-apocalyptic setting, with the PhysX card used to provide an ample visual rendition of the decimated locations. On some levels, smoke billows and can be blasted away by explosives or disturbed by movement; shreds of cloth hang from buildings and walls waiting to be punctured by stray bullets. On others levels, a cloud of ash and embers light the air and clouds your vision.

The game makes pretty good use of its hefty system requirements, and the art style is consistent and effective. In short... it's not exactly pretty - wrecked world and all - but it's ugly in a most agreeable fashion.

The technology is based around procedurally generated pre-fractured meshes. An artist designs the structures and objects to be placed within maps - as with any other game - and software then automatically creates the destroyed and fractured versions of these objects. This massively reduces the amount of artist time required to produce a destructible object. The artists only have to produce the original design, not the original design of say a wall, as well as several different broken variants of the same wall, which may only be visible for a few seconds. With little additional artist time required everything can become destructible, and hence Warmonger became possible.

Of course, other technology plays its part. The PhysX card and SDK powers the real-time physics calculations, controlling precisely how and when an object flies apart, and Epic's Unreal Engine 3 handles graphics, audio and networking, amongst other more mundane tasks. The system requirements are rather high. I presume the logic is that anyone with (or likely to acquire) a PhysX card at this stage is a dedicated gamer, and thus will have a system to match.

The game targets Internet play, which brings with it another limitation: that of bandwidth. Modern broadband connections still aren't particularly fast, and there's a definite limit as to how much data can be sent from the average home PC. Normally, this isn't an insurmountable problem for shooter-style games. Whilst it takes some work for the developers to keep the amount of data sent to a minimum, it is possible.

With Warmonger, however, replicating the precise physical effects seen by one player on every other screen would require a prohibitive amount of bandwidth. The movements of every smoke particle, piece of tile and lump of debris would have to be sent. This is obviously prohibitive, so physics effects which don't affect gameplay - such as the smoke and tile pieces - are calculated locally. Unfortunately, other effects which could be significant to gameplay must also be calculated locally: the falling debris is a good example. Only the fact that a section of wall was destroyed is transmitted across the network, not the precise location of the resulting debris. This makes it impossible to score frags with falling masonry, alas, but it's not a particularly huge loss.

There are games on the market today which offer some compelling set-pieces involving massive physical displays: collapsing structures and exploding vehicles and the like. Of course, many of these experiences take place as cut-scenes, or are similarly static. The calculations required to simulate physics on that scale in real-time being far too great. Warmonger allowed me to play a game based squarely on this level of physical manipulation. In effect, I was in control of the cut-scenes.

It's is not a large game. It falls somewhere between a full retail title and a tech demo. It primarily serves as a vehicle to show off Ageia's and NetDevil's technology, and to encourage new purchases of the PhysX card.

NetDevil have plans for future games based on this technology, perhaps allowing for construction of physics-based defensive structures, or rigid-body simulation of debris from destruction events. But, the current iteration is fun. And it's definitely a unique twist on a classic genre.