845GL datasheet(121/193 Pages) INTEL

121 / 193 page

Intel® 82845G/82845GL/82845GV GMCH Datasheet

121

Functional Description

Zone Rendering

Zone Rendering Technology is a unique mechanism that addresses memory bandwidth limitations

by reducing the required memory bandwidth for graphics. The 3D graphics engine divides the

frame buffer into rectangular zones and then sorts the triangles into memory by zone. The 3D

graphics engine then completely processes the zone, writing the pixel data to memory and then

proceeds to the next zone. By processing only a single zone of the frame buffer at a time, the use of

on-chip memory (cache) is highly optimized and each pixel in each scene is drawn only one time.

As a result, the system memory bandwidth required to render each scene is greatly reduced.

Depth-Bias

The GMCH supports source Depth biasing. The Depth bias value is specified in the vertex

command packet on a per primitive basis. The value ranges from -1 to 1. The Depth bias value is

added to the z or w value of the vertices. This is used for coplanar polygon priority. By using Depth

bias, it is possible to offset the destination z value (compare value) before comparing with the new

z value.

Backface Culling

The GMCH discards polygons from further processing, if they are facing away from or towards the

user’s viewpoint. This operation, referred to as “Back Face Culling,” is accomplished based on the

“clockwise” or “counter-clockwise” orientation of the vertices on a primitive. This can be enabled

or disabled by the driver.

4.4.1.2

Scan Converter

The Scan Converter takes the vertex and edge information is used to identify all pixels that are

affected by features being rendered. It works on a per-polygon basis.

Pixel Rasterization Rules

The GMCH supports both OpenGL and D3D pixel rasterization rules to determine whether a pixel

is filled by the triangle or line. For both D3D and OpenGL modes, a top-left filling convention for

filling geometry is used. Pixel rasterization rule on rectangle primitive is also supported using the

top-left fill convention.

4.4.1.3

2D Functionality

The alpha stretch BLT function can stretch source data in the X and Y directions to a destination

larger or smaller than the source. Stretch BLT functionality expands a region of memory into a

larger or smaller region using replication and interpolation. The stretch BLT function also provides

format conversion and data alignment.

4.4.1.4

Texture Engine

The GMCH allows an image, pattern, or video to be placed on the surface of a 3D polygon. The

texture processor performs texture color or chromakey matching, texture filtering (anisotropic,

trilinear and bilinear interpolation), and YUV-to-RGB conversions.

845GL bảng dữ liệu(PDF) 121 Page - Intel Corporation

845GL bảng dữ liệu(HTML) 121 Page - Intel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL