301467-005 Datasheet, PDF (236/426 Pages) Intel Corporation – Express Chipset

Functional Description
R
and two digital (SDVO ports B and C). The ports will be explained in more detail later in the
chapter.
The entire IGD is fed with data from its memory controller. The GMCH’s graphics performance
is directly related to the amount of bandwidth available. If the engines are not receiving data fast
enough from the memory controller (e.g., single-channel DDR333), the rest of the IGD will also
be affected.
The rest of this chapter will focus on explaining the IGD components, their limitations and
dependencies.
12.6.1
3D Engine
The 3D engine of GMCH has been designed with a deep pipelined architecture, where
performance is maximized by allowing each stage of the pipeline to simultaneously operate on
different primitives or portions of the same primitive. GMCH supports Perspective-Correct
Texture Mapping, Multitextures, Bump-Mapping, Cubic Environment Maps, Bilinear, Trilinear
and Anisotropic MIP mapped filtering, Gouraud shading, Alpha-blending, Vertex and Per Pixel
Fog and Z/W Buffering.
The 3D pipeline subsystem performs the 3D rendering acceleration. The main blocks of the
pipline are the Setup Engine, Scan Converter, Texture Pipeline, and Raster Pipeline. A typical
programming sequence would be to send instructions to set the state of the pipeline followed by
rending instructions containing 3D primitive vertex data.
The engine’s performance is dependent on the memory bandwidth available. Systems that have
more bandwidth available will outperform systems with less bandwidth. The engine’s
performance is also dependent on the core clock frequency. The higher the frequency, the more
data is processed.
12.6.2
12.6.2.1
Setup Engine
The setup stage of the pipeline takes the input data associated with each vertex of a 3D primitive
and computes the various parameters required for scan conversion. In formatting this data, the
GMCH maintains sub-pixel accuracy.
3D Primitives and Data Formats Support
The 3D primitives rendered by GMCH are points, lines, discrete triangles, line strips, triangle
strips, triangle fans and polygons. In addition to this, GMCH supports the Microsoft DirectX*
Flexible Vertex Format (FVF), which enables the application to specify a variable length of
parameter list obviating the need for sending unused information to the hardware. Strips, Fans and
Indexed Vertices as well as FVF, improve the vertex rate delivered to the setup engine
significantly.
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Datasheet