|
A |
|
| alpha |
A pixel's opacity in percent (0..100). A pixel with the maximum
alpha value is opaque, one with a value of zero is transparent, and one
with an intermediate value is translucent. |
| alpha channel |
Opacity of an image defined by an alpha value per each pixel,
either interleaved with the color components (for example, ARGB), or stored
in a separate alpha surface. TGA images or skins can contain an alpha
channel. |
| ambient |
Light and material property that illuminates all parts of an object
equally, regardless of their orientation, position, and surface characteristics.
|
| anisotropic filtering |
Mipmap filtering mode that compensates for anisotropic distortion.
|
| animation |
A sequence of frames withing a model (see frame).
|
| anisotropy |
Distortion visible in the image of a 3-D object whose surface
is oriented at an angle with respect to the viewing plane. The anisotropy
is measured as the elongation (length divided by width) of a screen pixel
that is inverse-mapped into texture space. |
| ARGB |
Alpha (opacity), red, green, and blue components of a pixel. Each
color is represented in memory by data in BGRA order. |
| array |
Group of elements organized into an array. Arrays make it simpler
to apply operations to the entire group. C-Script supports arrays for
variables and strings. |
| attach |
Connecting multiple objects to each other, for instance a weapon
to an actor. Done by C-Script. |
|
B |
|
| back buffer |
Nonvisible surface onto which the renderer draws the next image
while the front buffer displays the currently visible image. |
| back clipping plane |
Far boundary of a viewing frustum beyond which objects are not
rendered; set by clip_range (A5) or clip_far (A6+).
See also
"front clipping plane." |
| billboard |
Non-oriented sprite that is oriented so that it faces the viewer,
to give the appearance of a 3-D object in the scene. |
| bone |
Used for model animation. A bone controls a number of vertices of the model
mesh, and is linked to a 'parent' bone by a joint. If a bone moves or rotates,
all linked bones move or rotate with it. The model is animated by rotating
bones about their joints |
| bounding box |
A box around a model, for model collisions. Has not necessarily
the same size as the model, but is often smaller, depending on the requirements
for collision. |
| bump mapping |
Technique for simulating the appearance of rough surfaces in 3-D
scenes. Variations in depth are stored in a texture and applied to a primitive,
using standard texture-blending techniques. |
|
C |
|
| camera |
Predefined view object to define the default viewing position
and direction. |
| camera space |
The frame of reference in which the viewer is at the origin, looking
in the direction of the positive x-axis. Objects are transformed from
world space to camera space by using the view transformation. |
| client/server session |
Multiplayer mode in which only the server stores the
session's complete state. When one client changes something, it propagates the
change to the server. The server then determines which clients it must
inform of the change. |
| codec |
An abbreviation for compressor/decompressor. Software drivers
or hardware used to compress and decompress digital media for playing
media streams. |
| collision detection |
Process for determining whether objects collide with the scenery
or with other objects when moving. |
| color key |
A color value used for
pixel selection that enables transparent effects for overlay entities. Normally black is
used as transparency color. |
| color table |
Also called palette, array of n color values (normally RGB triples).
Used for 8-bit images to represent the color of pixels. |
| culling |
Removing a face from the list of faces to render. Faces can be
culled using a number of techniques including BSP or Portal Culling.
|
|
D |
|
| dark light |
Light source that removes illumination from a scene. A Dark light
is created by specifying negative values for the colors of the light.
|
| dead zone |
Area within the physical range of a joystick axis where the axis
is considered to be at the center. |
| decal |
Texture that is rendered directly onto a surface. |
| detail map |
Used for adding little details to terrain surfaces, like bumps and cracks
visible at close distance. Gamestudio uses the second skin as detail map. The
detail bitmap should be small (like 64x64), tiled, true color and medium
bright. An example (detail.pcx) is included in the template folder. Mipmaps
must be created after importing a detail map. |
| directional |
Description of a light source that is attached to a frame but
appears to illuminate all objects with equal intensity, as if it were
at an infinite distance from the objects. Directional light has orientation
but no position, and it is commonly used to simulate distant light sources,
such as the sun. |
| dither |
Method to display a range of colors with a limited palette. Each pixel on the
source image is represented by multiple pixels (usually a 2x2 square) on the
destination image. From a distance, the eye blends the multiple pixels into one
color that has more shades than the original palette. |
|
E |
|
| emissive property |
Material property that determines whether a material emits light. The emissive
property of a material is one of 3 properties that determines how the material
reflects light. |
|
F |
|
| face |
Single polygon in a mesh. |
| falloff |
Light attenuation between a spotlight's inner and outer cones.
|
| frame |
In a movie or sprite
animation, a single image. In model animation, a frame is a set of
vertex or bones positions that define a
single pose for a model. Frames have names that can be used in C-Script to
select a certain frame. A number of connected frames is a
scene. |
| front buffer |
Rectangle of memory that is translated by the graphics adapter
and displayed on the monitor or other output device. |
| front clipping plane |
Near boundary of a viewing frustum, set by clip_near.
Any object closer to the camera than the front clipping plane is not
rendered. The height of the front clipping plane defines the field
of view. See also "clipping plane." |
|
G |
|
| gamma |
The curve in the
function that maps changes in voltage to changes in brightness on a
phosphor screen. The change in voltage needed to produce a specified change in brightness is not constant across voltage
levels. Gamma correction is used to adapt brightness levels to the characteristic of
the monitor, or darken and brighten the image without loosing contrast.
|
|
H |
|
| HAL |
DirectX hardware abstraction layer (HAL) consists of hardware and
device driver mechanisms that insulate applications from device-specific
implementation details. If a capability requested by an application is
not implemented by the current hardware, the capability is emulated by
the software. |
| HEL |
DirectX hardware emulation layer. The HEL provides software-based emulation
of features that are not present in hardware. |
| host |
Also named server; in multiplayer, a virtual player who controls
the game and manages messages sent to all players in a session. |
| host byte order |
On an Intel x86
computer, the byte order for the system, or host, is little endian (low byte comes first). Network byte order is always
big endian (high byte comes first). |
| hull |
A special fixed size bounding box used for collisions with blocks, map entities
and terrain.
|
|
I |
|
| interlace |
To display a video frame in two fields. One field contains the
even lines of the frame, the other field contains the odd lines. During
playback, the lines in one field are displayed first, then the lines in
the second field are displayed. |
| interleaving |
The arrangement of video frames and audio samples in a file, such
that video data alternates with audio data at regular intervals. |
| interpolation |
A method which calculates the position of the vertices in a model between two
arbitrary frames.
|
|
K |
|
| key frame |
An animation frame containing all the data needed to render a
model without reference to previous frames. |
|
L |
|
| latency |
A delay in response. For example, in multiplayer mode, it is the
time that it takes for a packet to reach a specified destination. In playing
media streams, it is the amount of time it takes a filter to process a
sample. |
| light map |
Also named shadow map, a texture or group of textures that
contain lighting information for a 3-D scene. |
|
M |
|
| Mach bands |
Bands of color that are not smoothly blended across a 3-D primitive.
Sometimes visible when using 16-bit textures. |
| material |
Property that determines how a surface reflects light. A material
has two components: an emissive property (whether it emits light) and
a specular property, whose brightness is determined by a power setting.
|
| mesh |
Set of faces, each of which is described by a simple polygon.
|
| mipmap |
Also known as MIP map (Latin: multum in parvo, translated as "much
in little"). A sequence of textures, each of which is a progressively
lower-resolution, prefiltered representation of the same image. A higher-resolution
image is used when a visible object is close to the viewer. As the object
moves farther away (and gets smaller), lower-resolution images are used.
|
| model coordinates |
Coordinates that are relative to a local origin. See also "model
space" and "world coordinates." |
| model space |
Frame of reference (used by model coordinates) that uses vertices
relative to a single 3-D model's local origin. |
| multipass texture blending |
Repeated rendering of a 3-D primitive while blending on a texture
with each pass. This technique is widely used to achieve a variety of
special effects. |
|
N |
|
| nagling |
Algorithm to buffer small data packets into larger ones before
sending. Nagling prevents a TCP/IP protocol server from transmitting many
very small packets by requiring the server to wait either until it has
accumulated enough small data packets to combine them into a single large
packet or until it has received an acknowledgment of the prior packet.
Nagling can reduce message overhead (and decrease required bandwidth),
but also causes a delay before small data packets are sent (increasing
latency). |
| normal vector |
Imaginary ray extending perpendicularly from a surface that defines
the face's orientation. |
|
O |
|
| origin |
Position within a model or map with XYZ coordinates 0,0,0. Not necessarily
identical to the center of the model or map. |
| overlay |
An image with pixels
that are either fully opaque or fully transparent, dependent on a
transparency color (see color key). |
|
P |
|
| palette |
Set of colors used by an object or application. |
| palette index |
Integer index into the palette table array that is used to select
a particular color. |
| palettized image |
Image whose pixels contain palette indices rather than colors.
Normally an 8-bit image. |
| parallel point |
Description of a light source that illuminates objects with parallel
light, but the orientation of the light is taken from the position of
the parallel point light source. For example, two meshes on either side
of a parallel point light source are lit on the side that faces the position
of the source. |
| perspective correction |
Technique of applying a texture map to a polygon that is angled
away from the camera, interpolating so that the texture is stretched onto
the polygon appropriately for the apparent depth of the polygon. |
| pick |
To search for visuals
in a scene, given a 2-D coordinate in a viewport. Used for mouse
detection. |
| player |
Single participant in a multiplayer session. Each player is associated
with a player ID that enables messages to be exchanged among players.
|
| player ID |
Unique number that is assigned to each participant in a multiplayer
session when the participant is created. |
| point light |
Light source that radiates equally in all directions from its
origin. |
| power |
In the specular property of a material, value that determines
the sharpness of specular highlights. A value of 5 gives a metallic appearance,
and higher values give a more plastic appearance. |
| power of 2 |
A number that can be expressed as 2^n, like 16, 32, 64, 128, 256, 512, or 1024.
All textures in a game should be a power of 2 in horizontal and vertical size.
If they aren't, the engine interpolates them to the next power of 2, which
consumes video memory and rendering time and reduces the visual quality. |
| projection space |
Frame of reference containing vertices after they are modified
from their world space locations by the projection transformation. Projection
space is a homogeneous cuboid space in which all vertices in a scene have
x-coordinates and y-coordinates that range from -1.0 to 1.0, and a z-coordinate
that ranges from 0.0 to 1.0. Projection space is sometimes referred to
as post-perspective homogeneous space. |
|
Q |
|
| quality control |
Mechanism for adjusting the rate of data flow or media streams
in response to run-time conditions. |
| quaternion |
Fourth element added to the [x, y, z] values that define a vector.
Quaternions define a 3-D axis and a rotation around that axis. |
|
R |
|
| RGB |
Red, green, blue components of a color or pixel, normally in 0..255
range. Each color is represented in memory or in a vector in BGR order.
|
| rolloff |
The attenuation of sound over distance. |
|
S |
|
| scene |
Entire set of objects that make up a virtual environment, including
visible objects, sounds, lights, and frames. |
| screen space |
Frame of reference that relates 2-D coordinates to locations in
the frame buffer. Screen space coordinates typically display on a monitor.
The origin, or (0,0) is defined at the upper left corner. Y increases
in the downward direction; X increases to the right. |
| script |
A piece of text that contains a description of a behavior for
objects in a computer language. Writing a script is often referred to
as 'scripting' or 'programming'. |
| session |
In multiplayer mode, instance of several applications on remote
computers communicating with each other. Before an application can start
communicating with other computers, it must be part of a session. An application
can enumerate all the existing sessions on a network and join one of them,
or it can create a new session and wait for other computers to join it.
Once the application is part of a session, it can create a player and
exchange messages with all the other players in the session. |
| skin |
The image, or texture, that is wrapped around a model. Skins can be imported in
.PCX, .BMP, or .TGA format, 8 bit, 24 bit or 32 bit with alpha channel. Skins
can be of any size (not only 256x256), but should be powers of 2 in size for
rendering speed and quality reasons. The skin uses UV mapping, which means it
can be arbitrarily mapped onto the model parts.
|
| specular property |
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 the properties that determine how a material reflects light. |
| spotlight |
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 that acts as a point source, and a
surrounding dimly lit section that merges with the surrounding deep shadow.
|
| stretching |
Blitting an image into a destination with different dimensions. |
| surface |
A side of a block, or a triangle of a model |
|
T |
|
| TCP/IP |
Transmission Control Protocol/Internet Protocol. A protocol developed
by the Department of Defense for communications between computers. It
is built into the UNIX system and has become the standard for data transmission
over networks, including the Internet. The User Datagram Protocol (UDP)
TCP/IP service provider uses data packets for nonguaranteed and guaranteed
messaging. Using TCP/IP protocol, a single computer can host multiple
multiplayer sessions. |
| tearing |
A visual artifact that occurs when one displayed video frame contains
parts of two different source video frames. It is usually caused by improper
synchronization between video rendering and the graphics display. |
| tessellating |
Breaking an image or a polygon into small square regions. Normally
used for rendering lights on a surface. |
| texel |
Single element in a texture. When a texture has been applied to
an object, the texels rarely correspond to pixels on the screen. Applications
can use texture filtering to control how the system interpolates between
texels to create pixels in a scene. |
| texture |
Rectangular array of pixels that is applied to a visual object.
|
| texture blending |
Technique of combining the colors of a texture with the colors
of the surface to which the texture is applied. |
| texture coordinates |
Coordinates that determine which texel in each texture is assigned
to each vertex in an object. |
| texture filtering |
Process of mapping texel colors from one or more textures onto
the pixels that comprise the image of a 3-D primitive. |
| texture mapping |
Application of a texture to an object. Because a texture is a
flat image and the object is often not, the texture must be mapped to
the surface of the object, using texture coordinates and wrapping flags.
See also "texture coordinates" and "wrap." |
| thrashing |
Removing textures used in the current frame to reclaim texture
memory for subsequent frames. |
| time code |
A digital signal applied to a media stream. The signal assigns
a number to every frame of video, representing hours, minutes, seconds,
and frames. |
|
U |
|
| unit vector |
Vector with a magnitude
(length) of 1.0. Normals are always unit vectors. |
|
V |
|
| vertex |
Point in 3-D space, represented by three coordinates, it's X,
Y and Z position. |
| vertical blanking interval
|
Small period of time that elapses between video frames during
which a display device refreshes its display for the next frame. |
| vertical refresh |
Period after which the display is to begin a new screen. |
| video frame |
Single image in a video stream, comprised of one odd field and
one even field. See also "field." |
| view space |
See "camera space." |
| view state |
Accumulation of all a control's property values. |
| view transformation |
Application of a matrix to a model's vertices to change its orientation
from world space to view space. |
| viewing frustum |
3-D volume in a scene positioned relative to the viewport's camera.
Objects within the frustum are visible. For perspective viewing, the viewing
frustum is the volume of an imaginary pyramid that is between the front
clipping plane and the back clipping plane. For orthographic viewing,
the viewing frustum is cubic. |
| viewport |
Rectangle that defines how a 3-D scene is rendered into a 2-D
window, given by view parameters. |
|
W |
|
| WAV |
A file format in which Windows stores sounds as waveforms. Such
files have the extension .wav. |
| world coordinates |
Coordinates that are relative to the origin of a scene. See also
"model coordinates" and "world space." |
| world space |
Frame of reference used by world coordinates that declares vertices
relative to a single origin within a 3-D scene. |
| world transformation |
Application of a matrix to a model's vertices to change its orientation
from model space to world space. |
| wrap |
Procedure used to calculate texture coordinates for a face or
mesh. The basic wrapping types are flat, cylindrical, spherical, and chrome.
|
|
Z |
|
| z-buffer |
Buffer that stores a depth value for each pixel in a scene. Pixels
with a small z-value overwrite pixels with a large z-value. |
| z-beating |
Sawtooth like artifacts that result from a poor separation of
z-values due to far distances and low z buffer resolution. Some pixels
from the back texture are rendered onto the front texture and vice versa.
|