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New Age Graphics Moving Closer to Photorealism
What's the first thing that comes to mind when we talk of rendering a character for a game or an animation movie? Creepy monsters or funnily moving computer generated images that struggle to match the vivaciousness of our real life heroes. With newer and more powerful graphics equipment, all this is changing as we move closer and closer to achieving an artist's dream-photorealism
Monday, May 14, 2007
Tucked in a corner of a large, swanky office, a group of animators form a quiet huddle, glued to a large monitor, where an actress is portraying a series of human emotions ranging from laughter, confusion, relief, stress and depression. On another screen, you find a computer generated image trying to mimic those emotions. This is another test of the kind of photorealism that the latest graphics equipment in studios can achieve. The virtual characters seem to completely embody the personality of their real life counterparts.
More than the prominent cheek bones and the checkered brow, there is that intensity that seems to be emanating from deep inside the character's rendered body. And of course it's more than being a little bit weird. You can feel the subtleness of the inner part of the lips, the movement of the tongue or the eyes, to almost every aspect of human emotion. Then you notice the physics involved in the movements of the character, imitating those of the real character with full glory. Artists might love to call that soul transformation from the real to the reel character. But can you even imagine what kind of technologies or designs are involved in achieving such pristine graphics animation. It goes beyond the 700 million odd transistors that you normally have on processors. It even goes beyond the multi-core or multi-processor architecture that is almost ubiquitous or the ever more complex APIs to realize their full potential.
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Dermal Nanotech Display |
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Do these visuals look scary or exciting? Depends on whether you want to put your body to such use or not. This is an artist's imagination of a 'programmable dermal display' where about 3 billion pixel robots for display are permanently implanted just about a fraction of a mm under the epidermis, making up a 6 cm x 5 cm display area on the back of your palm. The display image is formed by photons emitted by these pixel bots. Each display shows the data received from all the medical bots flowing inside the body. And this is a two-way traffic. The same bots can be instructed by the user to perform specific tasks. What's more, the display can be activated or deactivated by a gentle tap of the finger on the skin surface! |
By the end of the 1990s, the usage of dedicated GPUs to provide visually intense, interactive 3D experience had become a norm. These GPUs grew in popularity as more and more graphics intensive applications such as Google Earth, Picasa and games such as Crysis, Halo 2, Flight Simulator, etc became available. To get into the minutest of detail of an object, you need processing power of several hundred cores and at extremely high speeds. In the quest to reach closer to life-like realism, the major graphics hardware and animation software vendors are involved in continuous research and development. The technology should ideally enable you to fathom each and every minute detail, be it the texture of the skin or the crevices in the walls of a building, the clouds in the sky or the discrete water drops in a waterfall. With the advancement in technologies to pack more and more transistors on a single die, the parallel processing power of a GPU can be harnessed in more ways than one.
Today, the processing power of even a multi-core CPU pales in comparison to the mammoth power that you can generate out of a GPU, and this chasm is steadily widening. Moreover, GPUs have crossed the thin line from being a fixed 3D graphics processing pipeline to become flexible general-purpose computational engines. These GPUs implement many parallel algorithms that use all the underlying computational power to achieve tremendous computing speeds. Let's take a look at some of the new techniques in this highly mesmerizing field.
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| Previously, there were separate processing pipelines for pixel and vertex shaders. But now these pipelines can be used by all shaders
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Unified Shader Architecture
The advent of DirectX 10 means that GPUs need to have an architecture to support its unified pipeline model. So we have graphics vendors coming up with Unified Shader Architecture. Earlier, game programmers had no control over transformation, lighting and pixel rendering mainly because all calculation models were fixed on the chip. Unified architecture has a single floating point shader core with multiple independent processors called stream processors. Each of these processors is capable of handling all shading operations: pixel, vertex, geometry and now even physics acceleration. In simpler terms, earlier you had separate pipelines for different shaders, where one of the pipelines used to be fully clogged while the other ones were under utilized, but now you have 100% utilization (see the infographic), thanks to unified shader processors (stream processors), that can be utilized simultaneously. So, the more the number of shader processors the better the processor utilization, resulting in more computing power and faster rendering. Previous generation shader units operate on data in a vector fashion, but now each is a scalar and thus can operate on only one component at a time, making them simple while being flexible at the same time. All this makes today's GPU much more efficient and powerful.
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