call of duty ghosts trailer 09 640x351During today’s coverage of the Xbox One, I think that most will agree that the epic reveal of Call of Duty Ghost was the best moment of the show. As a former game developer, I’ve always been impressed¬† by the quality of the work in this franchise, and since they’ve given us a peak at the production of Call of Duty Ghost, I wanted to do a quick overview of the technology behind this rather impressive title and how it relates to the Xbox One.

Much higher graphics details

It’s quite obvious that a next-gen title would feature a discontinuity in computer graphics quality when compared to the existing Xbox 360 and PS4. Call of Duty (CoD) Ghosts doesn’t disappoint and this is thanks to a few critical things which were not possible with current-gen consoles. Keep in mind that beyond the “specs”, a huge part of how good it looks is the result of the sheer talent of the game artists and graphics engineer working on this title. Kudos to them.

Behind the scenes video

1/ “Sub-D”

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Sub-D stands for Sub-division Surface, which is a technique that allows developers to describe an object not with a finite amount of triangles, but with mathematical equations controlled by an underlying mesh of triangles or quads. This allows the graphics processor to create as many polygons as needed in order to preserve the smooth curvature of objects through a process called “Tessellation“. This can be used not only to “add” details for nearby objects, but could be used to lower the level of details for far-away objects if used as a basic form of “level of details” (LOD) control.

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Weapon detail pushed to the extreme

Although these techniques have been invented a long time ago, they are only practical today on the Xbox One because the hardware and API (DirectX 11 here) provides good support for it. Expect to see this in more games.

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2/ More texture memory

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Few people realize it (or care), but the current-gen consoles have VERY little memory for developers to work with. What you see on current-gen console is extremely impressive relative to what they have to work with. With an increase in texture memory, the level of details in games will jump tremendously. We don’t yet know exactly what the maximum amount of memory can be allocated for this particular usage (especially if this is variable since Xbox One probably share the RAM between CPU and GPU), but CoD Ghosts clearly shows that there is much more to work with. In fact, you will see that the increase in system memory is one of the most important upgrades of this generation of consoles.

3/ Procedural elements

Given that artwork and engineering costs are sky-high, it is simply not possible to scale worlds to immense sizes by simply having more people create more content. There are many things that add realism to a game, including secondary animations or elements like grass, trees, birds or fish.¬† In the real world, we don’t pay attention to those but when they are missing, the immersive feel is deteriorated.

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CoD ghosts adds more procedural elements by using a fluid dynamics engine so that water and smoke can look and behave in a believable way. They also mentioned an artificial intelligence (A.I) system that controls fish in the water so that swim and act naturally, especially in the presence of humans.

Dynamic maps and physics allow every game to be different, even if you play on the same level, because when initial conditions changes, critical aspects of the levels will change as well. For example, an explosion may move steel barrels around that you can use for cover. This creates an infinite amount of possible scenarios based on an initial location.

All this work may have not been possible on current-gen consoles since CPU resources can be scarce and allocate to AI and gameplay. With 8 CPU cores, the next-gen consoles like Xbox One and PS4 can allocate resources to handle critical physics (that can also be offloaded to the GPU) or background procedural animations.

4/ Better lighting

Part of what makes characters more realistic is how their skin is lit. This is what makes the difference between “plastic” looking skin and “human skin”. It works this way: when light illuminates our skin, it just doesn’t hit and bounce off the skin towards a viewer. Instead, a large part of the incoming light goes through up to three layers of skin (epidermis, dermis and hypodermis) before bouncing back outside (at a different location) and go towards the viewer. Some layers of the skin contain more blood and blood vessels, and this is why we have that typical “fleshy” color.

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There are known techniques to do skin shading in real-time this, and although they have been adapted to current-gen consoles by the likes of Naughty Dog (PPT download link), the extra amount of RAM and GPU power make it possible to push this technique further and include self-shadowing for example.

I didn’t hear Activision talk about global illumination (GI) in their engine presentation, so I’m not sure that they have it, and none of the footage had an obvious GI feature, but this would be something that could further help realism. Games like Battlefield 3 and the next-gen Konami Fox Engine have had this for some time, so I’m curious to see where Activision stands on that.

Performance: 60FPS

What’s more impressive is that CoD Ghosts runs at 60 frames per second (FPS) at all times, which is a hallmark of that franchise. To give you an idea, 60FPS represents about 16 milliseconds (ms) per frame. To give you an idea, fetching an empty web page can routinely take 54ms. So in the time that it takes to fetch a “hello world” web page, Call of Duty Ghosts has computed more than 3 full frames of stunning HD graphics with animations, enemy AI, Physics & collisions.

Conclusion

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As you may expect, Xbox One represents a huge jump from the previous generation game consoles, and the bump in specs for the memory, CPU and GPU will form a powerful foundation for the coming years. If you want to compare that with a PC gaming rig, it is obvious that a PC is more powerful, there is no question about that, but at an expected sub-$500 cost, the next-gen consoles should be a pretty good deal when they hit.

Finally, this is the first generation of games on Xbox One, and history has shown that developers have always found ways to dramatically improve their products over the lifetime of a console. I can’t wait to see more titles on both Xbox One and PS4. Check the gallery below for more CoD Ghosts photos:

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