## S

saturation
  Adjustment to the extreme value of a range when the actual value approaches the extreme. If the maximum value in a range is 1,000 and the maximum saturation point is set to 900, then any value greater than 899 is adjusted to 1,000.
scene
  The entire set of objects that make up a virtual environment, including visible objects, sounds, lights, and frames. In Direct3D, the entire set of objects is contained by a root frame.
secondary sound buffer
  A section of audio memory that stores individual sounds that are played throughout an application. The sound can be played as a single event or as a looping sound that plays repeatedly. Secondary buffers can also play sounds that are larger than available sound-buffer memory; the buffer serves as a queue that stores the portions of the sound about to be played.
service provider
  A dynamic-link library used by DirectPlay to communicate over a network. The service provider contains all the network-specific code required to send and receive messages. Online services and network operators can supply service providers to use specialized hardware, protocols, communications media, and network resources.
session
  In DirectPlay, an instance of several applications on remote machines communicating with each other.
sound buffer
  A segment of memory that stores DirectSound audio data. Sound buffers can be primary or secondary, static or streaming.
source color key
  A color that, in the case of blitting, will not be copied, or, in the case of overlays, not be visible on the destination.
specular property
  The material property that determines how a point of light on a shiny object corresponds to the reflected light source. The specular property of a material is one of two properties that determines how a material reflects light. See also emissive property.
spotlight
  A light source that emits a cone of light. Only objects within the cone are illuminated. The cone produces light of two degrees of intensity, with a central brightly lit section (the umbra) that acts as a point source, and a surrounding dimly lit section (the penumbra) that merges with the surrounding deep shadow.
static sound buffer
  A section of memory that contains a complete sound. These buffers are convenient because the entire sound can be written once to the buffer.
sticky focus
  In DirectSound, the capability to play sound buffers when the owning application does not have the input focus. For example, a DirectSound application could continue to play a sound buffer while the user was working in another application.
streaming sound buffer
  A small sound buffer that can play lengthy sounds because the application dynamically loads audio data into the buffer as it plays. For example, an application could use a buffer that can hold 3 seconds of audio data to play a 2-minute sound. A streaming buffer requires much less memory than a static buffer.
stretching
  Blitting an image into a destination with different dimensions. This operation is supported directly by some hardware.
stride
  Synonymous with pitch. See also width.
surface
  Memory that represents visual images. This is often display memory, but it can be system memory. See also complex surface, off-screen surface, overlay surface, and primary surface.
sustain
  The period when the basic magnitude of a force feedback effect is attained, after the attack and before the fade.