8:57 AM
The Game Peddler
by Arthur Gies
Epic announced a host of new features in their Unreal Engine 3 development platform today at this year's GDC, the biggest of which is support for DirectX 11 and its assorted tools. The problem is, for most people, these kind of announcements might as well be in Sanskrit -- they're full of tech jargon that goes right by the average gamer.
I've gone through in an attempt to translate what Epic means by Subsurface Scattering and Deferred Rendering. The bolded segments are features of the updated Unreal Engine 3 courtesy of Epic, followed by our explanation of what this means for games. Epic gave us the thumbs up for accuracy. Yay, us.
Reflections are hard to do in games without wrecking performance. You'll notice that many games you'll play go out of their way to break any mirrored surface so that there's a plausible reason for them to avoid rendering your character's reflection. The solution Epic discusses here sounds like it'll take a simplified version of the scene around a reflected object (like, say, your character in a mirror or a polished metal surface) and apply all the different effects you'd expect on top of them.
Materials like skin and other non-shiny surfaces aren't opaque, believe it or not. Your skin is colored the way it is in part because of the color of the blood running through the capillaries in it, and you can see some veins. This also means that when light hits it, it doesn't just bounce off. Some light penetrates it, which then eventually reflects back. Subsurface scattering sort of emulates this effect with light that hits surfaces the developers designate. Think of the difference between a plastic action figure's skin surface and your own. That's what Epic is selling here.
Aliasing, put simply, is the jagged appearance that plagues edges in game visuals. Have you ever seen, say, a wire running diagonally from the ground to a structure that looked like it was a collection of horizontal lines laddering upward? That's aliasing. Anti-aliasing smooths these edges. There are a variety of means of anti-aliasing, but the most effective methods can be really hard on video cards. Hair is especially effected, because of its overall complexity. Epic is claiming a better implementation for materials like hair in the new version of Unreal Engine 3, as shown below.
If I understand correctly, this will help with things like grass and trees too. When you play games like Bad Company 2 on the consoles, you can see this kind of aliasing (jagged edges) in the bushes and such.
Deferred rendering has been a buzzword in game development circles for the last few years. Most engines use a forward renderer: this means the scene you see is drawn in passes - the environment, the figures, the lighting, other effects, etc (this is a simplified explanation, obviously).
Killzone and Dead Space use deferred rendering. Deferred renderers store all those passes I was talking about without drawing them until the last possible second, which allows developers to push the detail you're seeing and aggressively ramp up the lighting they can use. This kind of renderer has issues though, one of which being a lack of proper anti-aliasing support (which smooths out jagged edges in your games).
The new version of Unreal Engine 3 supports deferred rendering out of the box, and Epic is claiming to have solved the anti-aliasing issue, allowing M-ulti-S-ampling-Anti-Aliasing (the sort of default form of AA) to work with a deferred solution.
Bokeh can mean a couple of different things. At its most basic definition, it's the blur in out-of-focus areas of a photographic image. It also pertains to how "pleasing" that blur is. There are different definitions of what "pleasing" means for depth of field (DOF) blur, but generally it means a clean look that isn't especially distracting. Unreal Engine games have had DOF effects for a while, but they've been pretty hit and miss. This improvement in bokeh in UE3 will mean better, more film-like DOF effects, and also sounds like it'll allow more creative use of DOF, like we see in movies with great cinematography.
A dynamic shadow means a shadow generated, er, dynamically. That means it reacts to light sources "on-the-fly." This one's sort of self-explanatory right? Better shadows? Look at the screenshot. LOOK AT IT.
NOW LOOK AT ANOTHER ONE.
Epic also mentioned several other features, but the most interesting may be tessellation. Tessellation takes less complicated geometry and makes it more complicated.
This can mean a lot of things, but what it means to you is more detailed looking stuff with less system resources to do it. I grabbed some images from video card maker EVGA demonstrating some things that tessellation can do. Pictures say it better sometimes! And I can't think of a good way to explain how tessellation works without discussing geometry, and I can actually hear your head slumping onto your keyboard right now.
Tessellation in particular is a possibly major addition to Unreal Engine 3. The Xbox 360's graphics processor actually supports tessellation, but to my knowledge it's never been used. This alone could lead to some major enhancements to the visuals in 360 games - assuming that the 360 version of the Unreal Engine 3 development kit supports it.
I've gone through in an attempt to translate what Epic means by Subsurface Scattering and Deferred Rendering. The bolded segments are features of the updated Unreal Engine 3 courtesy of Epic, followed by our explanation of what this means for games. Epic gave us the thumbs up for accuracy. Yay, us.
"Image-based reflections that allow surfaces of any shape to reflect an approximate version of scenes, with varying glossiness across surfaces, anisotropic HDR highlights and anti-aliasing."
Reflections are hard to do in games without wrecking performance. You'll notice that many games you'll play go out of their way to break any mirrored surface so that there's a plausible reason for them to avoid rendering your character's reflection. The solution Epic discusses here sounds like it'll take a simplified version of the scene around a reflected object (like, say, your character in a mirror or a polished metal surface) and apply all the different effects you'd expect on top of them.
"Subsurface scattering (SSS) that simulates the light that scatters inside semi-translucent materials (this makes character skin come alive)."
Materials like skin and other non-shiny surfaces aren't opaque, believe it or not. Your skin is colored the way it is in part because of the color of the blood running through the capillaries in it, and you can see some veins. This also means that when light hits it, it doesn't just bounce off. Some light penetrates it, which then eventually reflects back. Subsurface scattering sort of emulates this effect with light that hits surfaces the developers designate. Think of the difference between a plastic action figure's skin surface and your own. That's what Epic is selling here.
"Anti-aliased masked materials that super sample the edges of masked and alpha-tested materials (this makes hair more look realistic than ever before)."
Aliasing, put simply, is the jagged appearance that plagues edges in game visuals. Have you ever seen, say, a wire running diagonally from the ground to a structure that looked like it was a collection of horizontal lines laddering upward? That's aliasing. Anti-aliasing smooths these edges. There are a variety of means of anti-aliasing, but the most effective methods can be really hard on video cards. Hair is especially effected, because of its overall complexity. Epic is claiming a better implementation for materials like hair in the new version of Unreal Engine 3, as shown below.
If I understand correctly, this will help with things like grass and trees too. When you play games like Bad Company 2 on the consoles, you can see this kind of aliasing (jagged edges) in the bushes and such.
Deferred rendering has been a buzzword in game development circles for the last few years. Most engines use a forward renderer: this means the scene you see is drawn in passes - the environment, the figures, the lighting, other effects, etc (this is a simplified explanation, obviously).
Killzone and Dead Space use deferred rendering. Deferred renderers store all those passes I was talking about without drawing them until the last possible second, which allows developers to push the detail you're seeing and aggressively ramp up the lighting they can use. This kind of renderer has issues though, one of which being a lack of proper anti-aliasing support (which smooths out jagged edges in your games).
The new version of Unreal Engine 3 supports deferred rendering out of the box, and Epic is claiming to have solved the anti-aliasing issue, allowing M-ulti-S-ampling-Anti-Aliasing (the sort of default form of AA) to work with a deferred solution.
"Bokeh depth of field providing close to film-quality DOF, with artist-controllable Bokeh."
Bokeh can mean a couple of different things. At its most basic definition, it's the blur in out-of-focus areas of a photographic image. It also pertains to how "pleasing" that blur is. There are different definitions of what "pleasing" means for depth of field (DOF) blur, but generally it means a clean look that isn't especially distracting. Unreal Engine games have had DOF effects for a while, but they've been pretty hit and miss. This improvement in bokeh in UE3 will mean better, more film-like DOF effects, and also sounds like it'll allow more creative use of DOF, like we see in movies with great cinematography.
"High-quality dynamic shadows from many lights on the environment (shadows for point lights and other light sources)."
A dynamic shadow means a shadow generated, er, dynamically. That means it reacts to light sources "on-the-fly." This one's sort of self-explanatory right? Better shadows? Look at the screenshot. LOOK AT IT.
NOW LOOK AT ANOTHER ONE.
Epic also mentioned several other features, but the most interesting may be tessellation. Tessellation takes less complicated geometry and makes it more complicated.
This can mean a lot of things, but what it means to you is more detailed looking stuff with less system resources to do it. I grabbed some images from video card maker EVGA demonstrating some things that tessellation can do. Pictures say it better sometimes! And I can't think of a good way to explain how tessellation works without discussing geometry, and I can actually hear your head slumping onto your keyboard right now.
Tessellation in particular is a possibly major addition to Unreal Engine 3. The Xbox 360's graphics processor actually supports tessellation, but to my knowledge it's never been used. This alone could lead to some major enhancements to the visuals in 360 games - assuming that the 360 version of the Unreal Engine 3 development kit supports it.
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