Alpha Blending : In computer graphics, each pixel
has three channels of color information--red, green, and blue--and
sometimes a fourth called the alpha channel. This channel controls the way
in which other graphics information is displayed, such as levels of
transparency or opacity. Alpha blending is the name for this type of
control, and it's used to simulate effects such as placing a piece of
glass in front of an object so that the object is completely visible
behind the glass, unviewable, or something in between.
: The extra layer of 8-bit greyscale carried by a 32-bit graphic. This
extra information is used to determine the transparency or edge
characteristics of the image.
: It is easy enough to make an object transparent when creating 3D
scenes, but in real life even glass isn't completely transparent,
particularly when viewed at an angle. Graphics cards supporting alpha
transparency are capable of taking into account the transparent and
translucent properties of particular objects.
Texture Filtering : This filtering samples from more than 8 pixels and
depends on the degree of surface tilting on X - Y - Z in different shapes
and therefore can produce better quality graphics. Anisotropic filtering
requires a higher fill rate than trilinear filtering, which means it is
slower. There are different levels of quality available depending on the
number of pixel samples (or "taps"). 64 tap anisotropic filtering offers
much higher quality than 8 tap anisotropic filtering, but again, is
slower. Anisotropic filtering is the latest filtering type to be
implemented in 3D accelerators.
: AA Hides the jagged effect of image diagonals by modulating the
intensity on either side of the diagonal boundaries. This creates a local
blurring along these edges and reduces the appearance of stepping. The
result is a smoother, far more realistic image. Also see: Real-Time
Full-Scene HW Anti-Aliasing .
API : A 3D
application programming interface which controls all aspects of the 3D
rendering process. Conflicting APIs exist, including Microsoft's DirectX
and Open GL, Glide, Intel's 3DR, Reality Lab and Brender. Most are custom
designed for either entertainment or serious 3D animation.
: Discards invisible back-facing polygons that can be eliminated from
the list of polygons that need further 3D rendering processing.
Bezier : A way
of mathematically describing a curve, used by graphics programs such as
MacroMedia FreeHand and Adobe Illustrator.
: An advanced form of filtering to simulate textures on a "cube" to
cover all sides of an image.
Filtering : 3D accelerators use an interpolation method to produce
smooth transitions between different pixels in the source texture. This is
done by sampling the four closest pixels of the source texture (or most
suitable mip-map) and interpolating these values before rendering each
single texel on screen.
Bitmap File :
A file in which every pixel on the screen is represented by a piece of
data in memory. These are usually graphics although some audio formats are
described as bitmapped as well.
Bit-Aligned- Block- Transfer. The process of copying pixels or other data
from one place in memory to another.
Lighting : Bi-directional Reflectance Distribution Function
(BRDF)-based lighting. When light makes contact with a material, three
types of interactions may occur: light reflection, light absorption, and
light transmittance. That is, some of the incident light is reflected,
some of the light is transmitted, and another portion of the light is
absorbed by the medium itself.
draw : Bresenham's line-drawing algorithm uses an iterative scheme. A
pixel is plotted at the starting coordinate of the line, and each
iteration of the algorithm increments the pixel one unit along the major,
or x-axis. The pixel is incremented along the minor, or y-axis, only when
a decision variable (based on the slope of the line) changes sign. A key
feature of the algorithm is that it requires only integer data and simple
arithmetic. This makes the algorithm very efficient and fast.
B-splines are a formulation (Barsky and Beatty, 1983) of B-spline curve
segments. Barsky introduced two new degrees of freedom- bias and tension-
which cab be applied either uniformly to the whole curve or non-uniformly
by varying their values along the curve.
Bump Mapping :
Bump mapping adds lighting detail to an otherwise flat surface, giving the
surface a "bumpy" look and feel. There are several methods for creating
bump mapping, one involves using paletted textures and the other involves
multi-pass rendering. Voodoo3 3D supports both these methods at full
rendering performance and with all filtering modes. In fact, Voodoo3
supports bump mapping at full speeds, in a single pass and single cyle.
This full speed approach to bump mapping makes Voodoo3 unique among
graphics architectures, offering full speed performance even while bump
patches : Unlike a natural cubic spline, a Catmull-Rom spline has
local control. This means that modifying one control point only affects
the part of the curve near that control point.
Clipping : The
triangle setup engine is a floating-point math processor that receives
vertex data and calculates all of the parameters that the rendering engine
will require. This unit ‘sets up’ and ‘clips’ the triangle for the
rendering engine. Clipping uses a guard band efficiently and also includes
a clip against Z<0.0 and Z>1.0. If you supply Z values outside that
range then they will not be rendered. Because polygons which are wholly
clipped out still need to be transformed it will be to your advantage to
remove many polygons before submitting them to the API.
Keying : Certain color (or a range of colors in Chroma Keying) will be
thought as totally transparent during blending of two images. For example,
a weather forecaster stands in front of a blue background and blends with
a weather map image forms the scene that you can see daily on
mapping : Cube environment mapping in hardware is a breakthrough image
quality feature that is fully supported by DirectX 7 and OpenGL that
allows developers to create accurate, real-time reflections. Accelerated
in hardware, cube environment mapping will free up the creativity of
developers to use reflections and specular lighting effects to create
interesting, immersive environments. By changing the map shape to a
six-sided cube, cube environment mapping offers a simple development path
to the creation of stunning, reflective images. With a cube map shape,
reflections are captured by the six projected faces of the cube map that
surround an object
Removing, from the processing pipeline to spare unneeded work, complete
objects and surfaces which are completely hidden by other objects, or are
facing away from the viewer (i.e. Backface culling) .
: A curved surface created from two or more curves.
Depth Cueing :
Reducing object's color and intensity as a function of its distance from
the observer. In layman's terms, the color and intensity of the surface of
an object changes depending on the distance from you.
: Diffuse lighting assumes the light hitting an object scatters in all
directions equally, so the brightness of the reflected light does not
depend at all on the position of the viewer. Sunlight on a playground is
an example in the real world of diffuse lighting.
Microsoft's API for 3D graphics. It is also one of the components of
DirectX and supported by all gaming-oriented 3D accelerators so far.
Microsoft Windows API designed to provide software developers with direct
access to low-level functions on PC periferals. Before DirectX,
programmers usually opted for the DOS environment, which was free of the
limited multimedia feature set that characterized Windows for many years.
Mapping : An extension of Bump Mapping in which textures are used to
move the surface, not just change the appearance of the texture
Dot product bump
mapping : Dot product bump mapping is a technique of encoding a bump
map in a texture, and then texture blending with a light vector. This
produces a grayscale value that can then be used to modulate with a
surface color or environment map.
Double Buffering :
All calculations and rendering steps must occur on hundreds to
thousands of polygons for each frame of an interactive program that needs
to update the display at a rate of between 15 and 30 times each second.
Double buffering gives the system a little breathing room by providing an
opportunity to render the next frame of a sequence into off-screen memory
that is then switched to the display while the memory containing the
formerly displayed frame can be cleared and re-painted with the next frame
to be displayed and so on.
Bump-mapping : Environment mapping is the process of mapping a texture
onto an object to create a mirror-like reflection effect. This is normally
done using a pre-computed spherical texture map representing the 3D space
around the object. Another method called cubic environment mapping creates
the 3D space for the static environment map using 6 textures (top, bottom,
4 sides) representing the surrounding area from the point of view of the
object. Creating the 3D space environment map is computationally expensive
which is why most are computed only once (static.) Dynamic environment
mapping recreates the texture used for the reflection every frame. This
creates a more realistic image but at a huge performance cost.
Fill Rate: The
number of pixels that can be rendered on screen per second. (Pixels, or
"picture elements," are literally the dots that appear on your computer
display.) A 3D accelerator card with extremely high pixel fill rates is a
must for serious gaming action. More...
Flat Shading :
Each polygon is drawn in a single color representing the interaction of
light with that part of the object. Flat shading results in a faceted
appearance where the underlying geometry is visible.
Fogging : Not
particularly relevant to CAD applications, fogging is a technique by which
objects can be reduced in colour intensity so that they appear to be
buried in a distant mist or fog. This technique can aid the impression of
distance, and can be used as a performance-saving feature in some games,
with fogging eliminating the need for distant objects to be drawn. It's
something of a double-edged sword, since fogging can require lots of
processing power. It is generally used to create atmospheric
Frame Buffer :
An area of RAM used to store the pixel data for a single screen image,
Frame Rate :
The number of complete screens or frames drawn per second (FPS). Higher
frame rates provide smoother motion.
Filtering : The Voodoo 3D architecture performs filtering operations
at full speeds under all single texture per pixel conditions. In fact,
Voodoo3 can perform trilinear filtering at full hardware speeds, suffering
no performance degradation. The Voodoo platform has been designed for
maximum game performance, which means sustained, high frame rates.
Functions or filtering that have substantial performance penalties are
essentially valueless to the game developer as their frame rates will
suffer an unacceptable frame rate penalty. Many other graphics
architectures claim advanced filtering techniques but perform them either
so slowly in hardware, or perform them in software, that there is a 4x,
8x, or possibly even a 16x performance penalty. These operations may
improve the visual quality of a single frame, but when enabled the game's
frame rate my drop from 30 frames per second, to 2 frames per second,
rendering the feature completely unusable. Voodoo performs advanced
filtering operations at full speed, allowing both for advanced image
quality as well as high frame rates.
Full 32-bit RGBA
with 1 pass : One subtle benefit of being able to render multiple
textures with one pass is that multiple passes can be avoided and color
computations can be performed in full 32-bit RGBA precision. For example,
to render a base texture combined with a lighting map in a graphics system
that can only render one texture per pass, the results of the first
rendering pass are typically truncated from 24-bit RGB to 16-bit RGB when
stored in the framebuffer. When this truncation is followed by a second
pass, visual anomalies often result, which can typically be seen as bands
Clipping : Guardband clipping is a way to deal with the problem of
clipping triangles to the screen in hardware. When triangles are clipped
to the screen in software - the triangles that fall off the edge of the
screen must be split into several smaller triangles that do fit on the
screen. This is expensive to do. The guardband allows our hardware to do
the same job efficiently.
: Also called "smooth shading." Rendering a polygon with smoothly
changing color across its face. Each vertex can have a unique color that
is blended evenly across the polygon. Reduces "banding," or abrupt color
changes, and enhances realism.
Accelerator : Basically, a graphics card which can (1) draw points,
lines and polygons, using only the polygons' 3-dimensional vertices, and
(2) map textures on polygons and/or shade polygons.
Surfaces (HOS) : Curved surface maps representing textures. includes
Bezier, B-Spline, Catmull-Rom spline patches.
Moving geometric objects from point A to point B… it is the mathematical
model of movement.
Level of Detail
(LOD) : Reduces depth of volumetric effects, especially when player is
near. Reduces particle counts, especially when player is inside the
Lighting is the 2ndt step in the 3D pipeline and provides high visual
impact. Lighting effects are essential for enhancing the realism of a
scene and bringing rendered images one more step closer to our perception
of the real world.
"M" stands for multi-sample. While the VSA-100 FSAA algorithm (aka
T-Buffer) relies on super-sampling FSAA method (where a unique texture
lookup is performed per subsample), in the multi-sampling method, used by
Spectre, only one texture lookup per *pixel* (so that all subsamples use
the same texture lookup value) is required. This is an optimization that
the workstation folks have done for years, and is visually unnoticeable.
However, it reduces the amount of texture lookup by a factor of 4 compared
to the VSA-100 method, so the performance for the Spectre M-buffer method
is therefore much better.
Mesh model : A
graphical model with a mesh surface constructed from polygons. The
polygons in a mesh are described by the graphics system as solid faces,
rather than as hollow polygons, as is the case with wireframe models.
Separate portions of mesh that make up the model are called polygon mesh
and quadrilateral mesh.
Mip Mapping :
This involves storing multiple copies of texture maps (generally two or
three), digitized at different resolutions. When a texture mapped polygon
is smaller than the texture image itself, undesirable effects result. Mip
mapping can provide a large version of a texture map for use when the
object is close to the viewer, and a small version of the texture map for
use when the object shrinks from view.
MIP Mapping LOD
Control : MIP Mapping LOD Control - This control changes the Level of
Detail (LOD) bias used for MIP mapping. Moving the slider control will
either add or subtract a bias from the LOD computed during MIP mapping,
making textures appear sharper or blurrier. This can result in improved
visual detail, but may reduce performance accordingly. It can also result
in texture aliasing if the sharpness level is set too high.
Textures : This is an important feature of any 3D graphics
accelerator. It refers to the ability of such an adapter to apply a
texture to a 3D object based on that object's distance from the viewpoint.
This requires modification of the texture and is applied either on a
per-pixel or per-triangle basis, with the latter being faster but less
Motion Blur :
With traditional computer generated images, a given frame showing an
object in motion will render that object with crisp, clean edges in each
frame. When viewing a full motion version of the scene based on these
images, the result is an unrealistic strobing effect (much like watching
someone move underneath a strobe light). This strobing effect is quite
different from the continuous, fluid motion of moving objects in real
MPEG : MPEG
(Moving Pictures Experts Group) is a group of people that meet under ISO
(the International Standards Organization) to generate standards for
digital video (sequences of images in time) and audio
: Voodoo 3D, by means of it's patent-pending architecture, has the
unique capability of rendering multiple textures onto a polygon in a
single pass and single cycle. Employing multiple Texture Mapping Units
(TMUs) that each render a completely independent texture onto a polygon,
makes multi-texturing a standard feature of a consumer game
spline : Between each pair of control points there is a cubic curve.
To make sure that curves join together smoothly, the first and second
derivative at the end of one curve must equal the the first and second
derivative start of the next one. Computing the natural cubic spline
essentially involves solving a system of simultaneous equations to make
sure this happens.
NCC Textures :
Voodoo3 offers a patented proprietary Narrow Channel Compression (NCC)
format for textures. NCC textures occupy 8 bits per texel just like
palettized textures, but the decompression table is 20 times smaller. This
makes switching textures much more efficient and allows applications to
use a different table per texture. Several arcade games use NCC textures
to offer the highest resolution textures possible without noticeable image
Texture Support : Support for numbers other than 2, 4, 8, 16, 32, 64,
128, 256, 512, etc. Usually this is used to describe the texture sizes
that an engine requires in order to make good use of video memory.
Textures that are not in powers of 2, like 33x24, would probably cause the
engine to run slower or maybe crash.
Open GL : A
set of specifications for a cross-platform 3D graphics API, developed
initially by Silicon Graphics Inc. There are several implementations of
Open GL, provided by different vendors. A Win32 version is provided by
Microsoft. Open GL includes routines for shading, texture mapping, texture
filtering, anti-aliasing, lighting, geometry transformations, etc. Most of
these functions can be hardware-accelerated.
color) : Increased internal precision of 52-bits (signed 13-bits per
RGBA color component), generating rendered images of substantially higher
quality. The higher dynamic range reduces darkening resulting in more
vibrant and realistic images.
: Voodoo3 fully supports 8-bit paletted textures, offering both 24-bit
RGB and RGBA formats. These formats are commonly used by game developers
and provide for high-quality artwork while greatly reducing the texture
memory requirements. Some competing designs either cannot filter paletted
textures or convert them to 16-bit or 24-bit textures in their drivers.
Voodoo2 3D can perform advanced filter on paletted textures, providing
both the texture memory savings and high-quality artwork needed by today's
Peripheral Component Interconnect. This is a self-configuring PC local
bus. Designed by Intel, PCI has gained wide acceptance (even by Apple, in
its PowerPC series).
Perlin Noise :
If you look at many things in nature, you will notice that they are
fractal. They have various levels of detail. A common example is the
outline of a mountain range. It contains large variations in height (the
mountains), medium variations (hills), small variations (boulders), tiny
variations (stones) . . . you could go on. Look at almost anything: the
distribution of patchy grass on a field, waves in the sea, the movements
of an ant, the movement of branches of a tree, patterns in marble, winds.
All these phenomena exhibit the same pattern of large and small
variations. The Perlin Noise function recreates this by simply adding up
noisy functions at a range of different scales.
Interpolated LOD : The most accurate approximation to per-pixel
mipmapping is per-pixel interpolated LOD. The host CPU typically computes
an LOD for each vertex of the polygon, and then the graphics subsystem
interpolates this LOD across the polygon. This imposes a severe
computational load on the host CPU as well as additional parameter data
transfer and setup requirements. Interpolation of LOD across a polygon is
also inaccurate resulting in both excessive blurriness as well as
: Using DOTPRODUCT3 texture blending to achieve this, it results in
true per-pixel lighting effects where the lighting equation is solved for
every pixel at render time.
Mipmapping : We believe the Voodoo architecture is in a class by
itself when it comes to mipmapping. As far as we know, Voodoo is the only
low-cost PC solution that performs accurate per-pixel mipmapping. While
every chip claims to support mipmapping, none implement an accurate
per-pixel mipmapping selection. Instead, they use a variety of short-cuts.
Voodoo computes an extremely accurate Level-Of-Detail (LOD) value for
every pixel rendered. This LOD value is used to select a mipmap for every
single pixel rendered, and can freely change from one pixel to the next.
It is very important to select the proper mipmap - an inappropriate
selection results in either excessive blurring of the texture or excessive
sharpness and therefore aliasing. This per-pixel computation requires
absolutely no host CPU intervention or assistance.
Per Polygon LOD :
The least accurate approximation to per-pixel mipmapping is per
polygon LOD. In this scheme, the host CPU or graphics subsystem computes
an LOD for each rendered polygon, and this one mipmap level is used for
rendering the entire polygon. This results in substantial errors for
larger polygons - the result being sections of the polygon that are either
excessively blurry or sharp. Even worse is an artifact known as LOD
"popping". This occurs when the graphics code decides to change the LOD
for a polygon for the new frame. When this occurs, the entire polygon
changes LOD becoming either twice as blurry or twice as sharp. This is
very noticeable and distracting, especially for large polygons. If the LOD
computation is slightly unstable, or if the frame to frame changes are
such that the LOD changes from one value to another and then back again,
the polygon will repeatedly "pop" between mipmap levels and result in an
extremely annoying visual artifact.
Correct Texture Mapping :
This texture-mapping process keeps scenery
looking realistic, particularly when looking down a long hallway or
corridor that's been rendered with large polygons. Without perspective
correction, the hallway might appear to bend into the vanishing point.
: Involves considerably more calculation than Flat and Gouraud
Shading, but results in the most realistic shading effects.
Pixel Shader :
Phong shading rendering algorythm calculates a color for every pixel
on an object's surface. The path that the light follows is not calculated
in Phong Shading, (as it is in ray tracing).
Polygon : The
basic 2D element from which 3D objects are constructed. Most polygons in
video games are triangles.
Standard geometric 3D objects - sphere, cube, cone, cylinder, square and
plane. Generic primitives are often used as building blocks for making
more complex models.
: Spot lights and head lamps can be rendered using projected textures.
In this case, the light's texture is projected onto polygons in the scene,
and a new set of texture coordinates for the projected are computed. The
projected texture is rendered at the same time the base texture for the
Color quantization is usually defined as a lossy image compression
operation that maps an original full color image to an image with a small
color palette. The goal of any quantization algorithm is minimization of a
perceived difference between the original and quantized images.
Ray Tracing :
A relatively simple algorythm with renders a scene by tracing a ray of
light pixel by pixel. Lighting values are calculated as rays travel around
the three-dimensional scene affecting the surfaces of objects.
Full-Scene HW Anti-Aliasing (FSAA): an instant upgrade to all PC games
for Windows 95 or better, Real-time Full-Scene HW Anti-Aliasing has long
been the "Holy Grail" in 3D computer graphics. The VSA-100 architecture
brings useable, full-compatible, and absolutely amazing AA to the PC for
the first time. FSAA Hides the jagged effect of image diagonals by
modulating the intensity on either side of the diagonal boundaries. This
creates a local blurring along these edges and reduces the appearance of
stepping. The result is a smoother, far more realistic image.
: Texturing flexibility by supporting N (8 for Spectre) independent,
unique textures applied per pixel in a single rendering pass. From
per-pixel bump mapping to turbulence and glass distortion types of
effects, 3D developers now have the flexibility and power to generate
Hollywood-quality visual effects in real-time. Also reflection on
: (also called soft reflectance) is a natural visual phenomenon. In
the real world, there are some semi-glossy surfaces, like polished wood or
brushed stainless steel, that will reflect objects with different degrees
of focus, depending on how close the object is to the surface. Hold a
pencil perpendicular to the surface, for example, and the part of the
pencil that's closest to the surface will reflect in sharp focus, but the
reflection will become increasingly blurry for parts of the pencil that
are further and further away from the surface.
: A simple reflection can be implemented using a reflection map. One
example of a reflection map is the effect of clouds reflected in a car's
rear window. When the rear window polygon is rendered, rays can be cast
from the viewer towards the vertices and upwards into the sky, indexing
into a sky texture. The sky texture and the texture for the rear window
(streaky glass for example) are then rendered simultaneously. This same
technique can also be applied to other shiny surfaces on the car, e.g. the
car's roof. Mirrors can also be rendered using this technique assuming
that a reflection map of the surrounding environment has been created
The process of creating an image on the screen from polygons,
textures, lights, and other graphical information, as opposed to
displaying pre-computed graphics and animation.
The number of pixels in height and width on a screen.
: Moving bone elements, textures wrapped around bone. "Skins" on
texture of elbow will stretch.
SLI : Scanline
Interleave is a mode in which two Pixelfx are connected and render in
alternate turns, one handling odd, the other handling even scanlines of
the actual output. Each Pixelfx stores only half of the image and half of
the depth buffer data in its own local framebuffer, effectively doubling
the number of pixels.
: Specular lighting is different than diffuse lighting because it does
depend on the position of the viewer as well as the direction of light and
orientation of the triangle being rendered. Shining a spotlight into a
dark corner of a room onto a TV set and looking at the hot spots on the
picture tube will show you specular lighting. Specular lighting captures
the mirror-like properties of an object so effects such as reflection and
glare are achievable.
: The stencil buffer is used to eliminate certain pixels from being
drawn. The stencil buffer acts the same way as a cardboard stencil used
with a can of spray paint. You can 'draw' values into the stencil buffer
using the normal rendering primitives. Then a stencil test can be defined
and stenciling enabled.
: Lines that are jagged, or stair-stepped, due to
Correction : Sub-pixel correction simply means drawing things
correctly. In other words, if a pixel is at position 0.1356, it is drawn
at exactly 0.1356 rather than at 0. The pixel is interpolated from the
actual coordinate, rather than just integer values.
The T-Buffer allows several key digital effects for improving photorealism
in real-time 3D graphics rendering. The primary purpose of 3dfx's T-Buffer
technology is to improve image quality. The challenge is exactly how to
narrow this gap between computer-generated 3D graphics and what users
typically see in real life, photography, and motion pictures. The T-Buffer
attempts to narrow the gap considerably by offering real-time hardware
acceleration of spatial anti-aliasing, motion blur, depth of field, and
some other closely-related effects.More...
Voodoo3 supports texture compression in the form of
palettized textures and a patent-pending proprietary Narrow Channel
Compression format. Texture compression allows applications to have
greater effective texture memory, making more efficient use of the
available texture storage, as well as maximizing texturing performance as
each texture downloaded can be smaller in size, minimizing the bandwidth
: Bilinear or trilinear filtering, also known as sub-texel
positioning. If a pixel is in between texels, the program colors the pixel
with an average of the texels' colors instead of assigning it the exact
color of a single texel.
Texture Mapping :
The process of placing a bitmap image, or texture, on a surface during
rendering. For example, a photograph of bricks is placed on a polygon to
create the illusion of a brick wall. Texture mapping is essential to
creating realistic 3D worlds.
Transition minimized differential signal. This signaling is required to
connect graphics engines to the DVI (digital video interface)
The transform engine converts 3D data from one frame of reference to a
new frame of reference. The system must transform the data to the current
view before performing the following steps (lighting, triangle setup and
rendering). Every object that is displayed and some objects that are not
displayed must be transformed every time the scene is redrawn.
Lighting, & Clipping :
Geometry setup of vertices of 3D model
before entering 3D pipeline
: Employed to smooth out edges of mip mapped polygons and prevent
moving objects from displaying a distracting 'sparkle' resulting from
mismatched texture intersections.
Trilinear mipmapping is one of the highest quality texture
filtering methods available, requiring 8 texture samples and three linear
interpolations (thus the name trilinear). Trilinear mipmapping looks
better than bilinear mipmapping because it eliminates mipmap bands which
appear within a polygon when the rendering engine switches from one mipmap
level to another mipmap level. Trilinear mipmapping blends between mipmap
levels, producing a smooth transition between mipmap levels with no
banding. In many textures, mipmap bands are not noticeable, but in other
textures they are very distracting.
Filtering : Samples eight pixels and interpolates these before
rendering. This is twice as much as bi-linear does. Tri-linear filtering
always uses mip-mapping.
Vertex : A
point in 3D space that defines a corner of one or more
Vertex cache :
Can save on AGP B/W & transform cost. Vertex cache typically lies
after the transformation and lighting engines and before the setup engine.
This means that data which has already been transformed and lit can be
accessed more rapidly than data which needs to be fetched anew. The cache
allows higher peak polygon throughput rates and is of most importance when
the main load is on the lighting engine. The vertex cache only applies if
you use indexed data.
: DX8 shading operations.
W-Buffer : The
W-Buffer is basically the same as the Z-Buffer, but it inverts the Z
values. For hidden surfaces, if you use a Z-buffer, it would grab straight
Z values to determine locations. Using a W-buffer, the Z values are stored
inverted, therefore more precise (because of extra decimal precision
required for inverted values). This in turn would likely have less
artifacts than the simple Z value calculations.
Z-Buffer : An
area in graphics memory reserved for storing the Z-axis value of each
pixel. This Z-axis value is the measurement of how close the object is to
the viewer. The lower the value, the closer the object. This accounts for
certain objects overlaping others in a 3D environment.
Copyright 2000, 3dfx Interactive, Inc.
All rights reserved.