ATi Radeon X800 XT & X800 Pro - Heart Burn For The NV40

Article Index

3Dc Normal Map Compression Technology


While the R420 may be lacking in future PS3.0 support, it does bring to the table support for performance optimization and better resource utilization for another forward looking technique called a "Normal Map".

Radeon X800 XT and Pro Memory Controller and 3Dc
High Speed GDDR3 Interface and Compression For Normal Maps

Think of a Normal Map as method of increasing character or scenery detail, without having to rely as heavily on high resolution textures or higher polygon counts, both of which are frame rate killers and resource hogs.


Without getting into a mother-load of techno-babble, in short, a Normal Map is developed by calculating the differences in lighting and shading on surfaces of a high polygon count model versus it's base low polygon count version.  This surface lighting on an image gives a feeling of depth and 3D detail.  Rather than utilizing high res textures or high polygon counts to make more life-like models, Game Developers can apply Normal Maps to low polygon count models, allowing for better performance with the same level of intricate detail.  In a nut-shell, Normal Maps are essentially a type of texture that stores the "normals" of lighting effects on highly detailed surfaces.

Of course there's no such thing as a free lunch and Normal Maps, since they are basically textures, also require large amounts of texture memory as a result.  If used on all surfaces, they double required texture memory.  As such, compression techniques are essential but Normal Maps don't work well with current texture compression techniques like those used in DXTC.  This is where ATi's new 3Dc technology comes into play, since it has the ability to compress Normal Maps with little or no loss, as you can see in the screen shot above.

Obviously, 3Dc and the use of Normal Maps, are things that have to be supported at the developer level for next generation game engines.  As a result, like NVIDIA is pushing PS3.0 adoption, we'll see ATi leading the Normal Map charge.  

Here's a brief list of game engines that will make use of Normal Maps and take advantage of ATi's new 3Dc compression technology:

  • Valve - Half Life 2
  • Croteam - Serious Sam 2
  • Irrational Games - Tribes Vengeance
  • Pseudo Interactive - darkSector
  • Ritual Entertainment
  • Firaxis - Pirates
  • Digital Extremes


Related content