If geometry is tessellated, the cobblestones are actually 3D, as seen in the lower-right screen. The tessellation in the cobblestone image is handled by a technique known as displacement mapping. A displacement map is just a special grayscale texture map in which different shades of gray define how much the geometry is displaced.
Cobblestones are nice, but will we ever see differences in real games? Let's look at the recently released Metro below. The left image is the game with tessellation disabled; tessellation is enabled in the right image. Note how the object is more rounded in the second shot.
The effect is somewhat subtle here, but the point stands: This is the beginning of the end of polygonal heads. Tessellation means that character heads will someday all be rounder. In this sceen from Metro , you can see how tessellation makes it possible to create curved edges. Yet another example of tessellation, from the DirectX SDK, shows a technique known as subdivision surfaces below. The key idea in this technique is to start with a basic set of polygons, then divide them in ways that make sense for the object at hand.
In this character model, we overlay the textures on top of the visible wireframe. You can see the additional geometry added in the right-side screen, as well as the more naturalistic, rounded features. Tessellation is great for creating rounder heads and more realistic cobblestones. But it has other uses, too. Take water, for example.
Instead of using pixel shaders to build better-looking water, just add more triangles… a lot more triangles, as in the case of the Nvidia Island demo. Tessellation makes water appear more real in Nvidia's Island demo.
In the new racing game Dirt 2, cars driving through water will throw up waves in the DirectX 11 version of the game, using hardware tessellation to generate hundreds of triangles to form the effect. In DX9 mode, you see some spray, but no waves, and the water puddle itself can be as few as two triangles.
Tessellation adds waves and ripples to a scene in Dirt 2. Tessellation offers the promise of better, more realistic-looking 3D objects, but it's no panacea. As with any new technique, developers will have to be smart about its implementing. It's easy to use tessellation to create objects that look wrong. On top of that, there's the performance issue.
Turn up tessellation too much, and you'll see a severe performance hit. Game developers will likely use the technology as part of sophisticated LoD level of detail schemes where close-up, important objects characters are tessellated, while distant or unimportant objects are tessellated less-or not at all. Better-quality antialiasing with transparent textures was heavily touted by both Nvidia and AMD just a couple of years ago. Nvidia called this transparency antialiasing while AMD's term was adaptive antialiasing.
This is a classic case of a feature that improves image quality at the time, but isn't really considered bleeding-edge these days. The problem lies with the way transparency is handled in many games. Transparent objects are polygons with texture maps applied where some of the texture is transparent. Examples of this are chain-link fences, bare tree limbs, and overhead wires.
Adaptive antialiasing essentially smooths out the edges bordering on the transparent areas within those textures. Think of it as AA inside the polygon. Transparency, or adaptive, antialiasing works well when a game supports it as seen in the screen above , but tessellation could provide a universal substitute. For transparent AA to work, the game must test for alpha the transparent part , but also disable alpha blend where the transparent texture is combined with a background color to create a new color.
This is sometimes used to create translucent partially transparent objects. Valve's Source game engine does this, so if you enable adaptive antialiasing AMD or transparent antialiasing Nvidia in the graphics control panel, you'll see the effect, as in the Left 4 Dead screenshot here. However, alpha blending and other techniques are used that prevent these techniques from working. For example, enabling the feature has no effect at all in most games that use the Unreal game engine.
Also, technologies like tessellation may eventually make transparency AA obsolete. If those bare tree limbs can be built with polygons representing the limbs themselves, those polygons can be antialiased with standard multisampling AA, and you don't need to mess around with adaptive AA. It's all about light. Without light, you can't see.
In 3D games, all lighting is created using mathematical cheats-approximations of how real-world lighting behaves. Some of the most interesting lighting effects lie in the absence of light: darkness and shadows. Shadows have evolved from simplistic shadow maps-where the shadows all looked the same from any angle-to the more sophisticated techniques used in today's games. Variations on ambient occlusion are becoming increasingly more popular.
Ambient occlusion takes into account how light falls on objects to create shadows, and that the properties of light and shadows change over distance. Crysis was one of the first games to attempt a form of ambient occlusion, known as screen space ambient occlusion SSAO. SSAO techniques try to determine where a point in the scene exists relative to other points, and the effect that light falling onto that point has on other parts of the scene.
Objects have reflective properties, and may in turn bounce light to other parts of the scene-even those blocked from the direct light source. Real-world objects tend to have crevices, wrinkles, and depressions, which may not be directly lit by a light source the sun, for example. You also have the option to opt-out of these cookies. But opting out of some of these cookies may have an effect on your browsing experience. Necessary Necessary. Necessary cookies are absolutely essential for the website to function properly.
This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information. A lot of modellers do this already using the CPU but when the assembly gets larger, the processing time can be huge. Using shaders could solve this. Tessellation is the process of transforming data and adapting it for another purpose, on the fly.
It can take an existing mesh and enhance certain sections of a model to give more detail. It can also be used the other way round to reduce detail in a scene. For example, in a landscape the far off detail is not required, so it can be reduced to increase real time 3D performance or reduce render times. DX 11 enhances the use of these inside a viewport where there are options to interact with applying them. There is often a lot of confusion between rasteriser and ray tracing when people see realtime shader effects.
All of these functions add realism to any 3D application including CAD. In order to make use of these new capabilities, a DirectX 11 compatible graphics card is required, but the raw hardware can also be utilised by OpenGL and OpenCL, which is used to execute across heterogeneous platforms consisting of CPUs, GPUs, and other processors tinyurl.
The recently announced OpenGL 4. OpenGL 3.
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