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Gamer's Glossary

• DirectX: This set of application programming interfaces (APIs) was created by Microsoft to help programmers write multimedia applications that will work on any Windows PC, regardless of its hardware configuration. DirectX also allows programmers to make sure that their apps (games, for example) can take advantage of advanced hardware capabilities for faster performance, and it helps graphics board vendors create specialized drivers that get the most out of a graphics chip set.
  
  
• Direct3D: One of Microsoft's DirectX APIs, Direct3D consists of a set of procedures for interacting with computer hardware, such as a graphics card. Complex graphics and game programs use Direct3D or OpenGL to draw 3D scenes.
  
  
• OpenGL: Open Graphics Library, or OpenGL, is a set of APIs originally developed by Silicon Graphics. This programming standard is used for displaying graphics.
  
  
• Curved-surface support: This technique allows developers to model 3D objects using curves, rather than a fixed number of polygons. Graphics hardware then breaks the curves into a more manageable number of polygons to render the objects. Curved-surface support reduces the amount of information that passes from the CPU to the graphics card, and it permits more-realistic 3D models--although portraying complex objects, such as a human form, can be very difficult using curves.
  
  
• Multiple-matrix skinning: Movement of many 3D models is shown using skeletal animation, a technique in which a "skin" of polygons is stretched around invisible bones in the model. Graphics cards that support multiple-matrix skinning accelerate this animation technique, and they can use more matrices or control points around joints to provide more-realistic animation.
  
  
• Key-frame interpolation: Graphics hardware and software use this animation technique to move an object between two positions, or key frames. Using the key frames as starting and ending points, an algorithm plots a smooth path to move the object from one position to another.