Graphics Superguide: GeForce GTX200, CUDA, Dunia, Far Cry 2, S.T.A.L.K.E.R Clear Sky
There’s a new engine – Dunia – which the developers describe as being ‘kickass enough’ for the environment they want to create and they intend that Far Cry 2 will be the first of many games to use it. The demo we saw at Nvidia Editor’s Day on the GTX280 showed fabulously high resolution, high frame-rate, high-quality gameplay. There’s not just a full world: there’s also weather, 24-hour changes over four hours of game time, levels of intersecting shadows in the environment and independent behaviours for fire, trees and movements. Everything is animated, rather than programmed, and it looks amazing.
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| The goal for the Far Cry 2 team is not just to have great static screenshots, but also to have the best looking dynamic beauty. (Click image to enlarge) |
Other games we saw showed off aspects of the new PhysX inclusion, Morpheme – which allows completely interactive tackling in American Football game Backbreaker, for example, as each player behaves independently. RealTime Worlds, but the makers of Grand Theft Auto, looks to be particularly ambitious, boasting thousands of simultaneously physical objects, sychronised to the computers of millions of players around the world, each with independent behaviour, so if you kick a can on your screen, it’ll richochet through someone elses, too.
S.T.A.L.K.E.R Clear Sky showed off improved, more realistic shadows and dynamic wetting as well as incredibly realistic volumetric smoke and lighting in its demo.
Tegra – perpetual motion machine anyone?
We had a sneak preview of Nvidia’s new low-power platform Tegra at the Nvidia Editor’s day, fitted into the shell of a 12in laptop, showing a 720p video on-screen. The whole operation consumed three Watts – which Nvidia claims is around 10% that used by the new Atom-based Eee PC. The Tegra is built with portable devices in mind, much like Intel’s Atom, but where Intel opted for a CPU, Tegra has an inbuilt CPU, GeForce GPU and controllers for all other core operations in just 144mm2.
Tiny size doesn’t mean tiny performance, though. Both models of Tegra code and decode 720p for up to 30 hours of playback, play Quake 3 at playable framerates or play up to 130 hours of audio. The Tegra 650 can also play 10 hours of 1080p on a single battery charge.
Nvidia is planning Tegra II and Tegra III over the next couple of years to continue meeting consumer expectations of power and energy efficiency. By early 2009, we’re likely to see Nvidia’s first Tegra-based Eee-killer, sporting the next generation of Windows Mobile operating systems.
CUDA – the powerhouse behind the chip
Over the last 15 years Nvidia has focused on the graphics pipeline, but more recently its been concentrating on programmability to extend the use of the GPU beyond gaming. GPGPU (General-Purpose computation on GPUs) started out in universities, using the Cg programming language to program shaders and run programs deep inside the graphics pipeline. CUDA lets you write the same kind of program and run it outside of the graphics pipeline. That meant that it had applications outside gaming, for computational methods and database management.
Not only that, but CUDA’s programming environment can control both CPU and GPU cores for maximum processing power. CUDA is included with everything Nvidia ships, from GeForce through to professional level Quadro and Tesla GPUs, so developers can work on a laptop before porting the application to a larger scale.
If you have a series 8 GeForce GPU, it’s CUDA capable – giving you a free processor with your GPU. Over 60,000 people are using CUDA worldwide in just that manner.
For scientists, it’s meant that programs and tools run 100 times faster. An example of CUDA’s impact is The US National Centre for Atmospheric Research, which used CUDA to trim a week off the month-long weather research and forecast calculations (used to predict the weather 4-5 days in advance).
The programmable graphics of CUDA also has applications in future gaming. Traditonally, GPUs can be used to render and simulate complex light scattering, including subsurface scattering, to create very realistic shapes and surfaces.
However, with most of the traditional rendering techniques, objects like a hairball are very difficult to create because of the interaction of light with complex geometry, and because of shadows. To recreate that effect requires very small pieces of geometry that are very time-consuming to generate.
Nvidia’s view is that the next generation of high quality rendering will mix APIs and programming with CUDA and other C/C++ languages using rasterisation and ray tracing. Nvidia is putting a lot of money into ray tracing – in particular, it acquired University of Utah spinoff RayScale as part of its plans. The downside is that raytracing is computationally intensive, and until recently GPUs couldn’t manage it. In the envisaged scenario, the GPU does the rendering and physical simulation – the parallel supercomputer doing its work – while lighting and reflections are handled by raytracing.
We were showed a demo of a car and plane created entirely on GPU, with first pass all done with rasteriser and all reflections done using a raytracer coded in CUDA. The demo included interobject reflections, which gaming engines can’t do, but ray-tracing can. Nvidia aim to enable real time rendering and ray-tracing in their next generation processors.
The types of performance improvement that CUDA can add are useful even for desktop applications, such as transcoding HD video to H.264 for portable video. Nvidia claims, for example, that a 2hr HD movie transcode takes 10 hours using 1.6 GHz dual-core and integrated graphics, 5hr 33min with a 3GHz quad-core and integrated graphics, but only 35mins using a 1.6GHz dual-core and a GeForce GTX280.
The exciting range of upcoming games, and the ability to speed up video and audio encoding are just a few of the areas where we’ll reap rewards in the near future.
This article appeared in the August, 2008 issue of PC Authority.
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