Matrox Mystique Glossary

Matrox Game Arcade
Confused about some of the technical 3D terms
found on these documents? The following
definitions should help you...

3D graphics Graphical representation of a scene or object along three axes of reference: height, width and depth (x,y, and z) to make it look more realistic. Technique often used in scientific modeling or visualization and growing in the entertainment market

Bitmap Two-dimensional image

Texture mapping Warping of a bitmap onto a 3D object or polygon to enhance realism

Perspective correct texture mapping Texture warping is performed with correction for proper perspective. This feature is very important in creating a realistic representation of the 3D scene, and it reduces gross artifacts, present in non-perspective correct rendering

Shaded or Lit textures Texture mapped objects or polygons to which the element of light have been added to accentuate a shape or a perspective. Especially useful to emphasize the curve of an object

Texture Transparency (or Chroma Keying) Ability of the hardware to recognize a key color within a texture map and make it "transparent" when warping the texture onto a polygon. This feature is useful as not all objects are easily modeled with polygons. Using transparency, these detailed objects can therefore be easily included in the scene as texture maps

Texture compression Reduces storage requirements of texture information in offscreen memory, therefore allowing more detailed bitmaps, or more textures maps, to be used. The Matrox Mystique uses a proprietary compression algorithm which allows it to store up to four times more CLUT8 textures, allowing for more detailed game scenes

CLUT4 This stands for 4-bit Color Look Up Table. The CLUT4 is used as a palette for a piece of artwork to be used as a source texture map. This is a way of specifying the color of each source texel in a texel map with only 4 bits of information. This means that the source texture map only has 16 different colors inherent to it. While this is limiting, it is still appropriate for simple textures such as brick patterns. The Matrox Mystique converts this palletized information into a 16-bit RGB value and then performs true color lighting, etc. on it before integrating it into the 16-bit display buffer. With the Matrox Mystique, a different palette may be associated with each source texture map

CLUT8 This stands for 8-bit Color Look Up Table. Similar to the CLUT4, the CLUT8 is extremely useful as it provides a 2-1 compression over 16-bit artwork, but provides virtually the same color content. Each source texture map may have its own unique 256 entry palette associated with it, which is dynamically converted to 16-bit color by the Matrox Mystique at runtime

Z-buffering Checking the z-value, or depth, of each pixel to be drawn against other pixels', in order to determine which pixels or polygons will be drawn and which will be hidden. The z-buffer is a portion of off-screen memory reserved to store the z-value of each pixel

Double Buffering Technique of dividing the frame buffer into two areas, one drawing buffer and one display buffer. This allows the application to display a frame of animation from one buffer while drawing the next frame into the other, therefore making 3D animation smooth

PCI Bus Master By acting as a PCI bus master, the Matrox Mystique is able to fetch data directly from system memory without requiring interaction by the host CPU. This is a vital component of making a fast 3D rendering engine, as sending both the command lists of polygons and the texture maps directly into offscreen frame buffer memory adds significant rendering speed

Direct 3D 3D application developers interface established by Microsoft under Windows 95, which allows 3D software developers to take advantage of installed Direct3D-compatible hardware

Color Space Conversion Conversion of digital information into a different color format. Generally used for digital video playback, to convert video data which is typically compressed in YUV format into RGB information for the monitor

Scaling Making an image larger (up scaling) or smaller (down scaling) than its original size. Used mostly in video playback to make video window larger

Pixel duplication (or replication) A method of upscaling where pixel values are simply repeated to make a larger overall image. This results in a blocky looking video image

Interpolation A method of upscaling where pixel values are obtained by averaging between adjacent pixels to calculate the color information displayed. This method drastically reduces the blocky artifacts found when using simple pixel replication

Front-end scaling Superior method of scaling which takes advantage of a shared frame buffer access to deliver high quality video scaling. This approach is supported by Microsoft's DirectDraw

Single-ported memory A memory device wherein both the graphics controller and the RAMDAC have to share a single port to access the memory. When the RAMDAC is reading information from the memory to refresh the display, the graphics engine is not capable of performing drawing operations. Therefore, as display refresh takes up more bandwidth in high resolutions, high refresh rates or high color depths, the graphics engine is stalled waiting for the RAMDAC to finish displaying

Dual-ported memory A memory device wherein the graphics controller and the RAMDAC each have a separate port to access the display memory. Because of this the graphics engine always has access to the memory, and drawing operations do not take a performance hit in response to higher resolutions, higher color depths or higher refresh rates

Dual Bank This term is used in reference to a feature of SGRAM which the Matrox Mystique utilizes. This feature is the capability of having two separate pages in video memory open simultaneously. Most other memory architectures can only have a single page in memory open at one time. Since page breaks - incurred by opening new pages in memory - negatively impact performance, the ability to have two pages open at once drastically improves performance



For more information on 3D technology, read "Anatomy of a 3D games accelerator" white paper.


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