JG82852GMSL7VP Datasheet, PDF (134/176 Pages) Intel Corporation – Intel® 852GM/852GMV Chipset Intel® 852GM/852GMV Chipset Hub (GMCH)

Functional Description
R
5.4.3.10.
Projective Textures
The GMCH supports two simultaneous projective textures at full rate processing. These textures require
three floating-point texture coordinates to be included in the FVF format. Projective textures enable
special effects such as projecting spot light textures obliquely onto walls, etc.
5.4.4.
5.4.4.1.
5.4.4.2.
2D Engine
The GMCH provides an extensive set of 2D instructions and 2D HW acceleration for block transfers of
data (BLTs). The BLT engine provides the ability to copy a source block of data to a destination and
perform operations (e.g., ROP1, ROP2, and ROP3) on the data using a pattern, and/or another
destination. The Stretch BLT engine is used to move source data to a destination that need not be the
same size, with source transparency. Performing these common tasks in hardware reduces CPU load,
and thus improves performance.
256-Bit Pattern Fill and BLT Engine
Use of this BLT engine accelerates the Graphical User Interface (GUI) of Microsoft* Windows*. The
GMCH BLT Engine provides hardware acceleration of block transfers of pixel data for many common
Windows operations. The term BLT refers to a block transfer of pixel data between System Memory
locations. The BLT engine can be used for the following:
Move rectangular blocks of data between System Memory locations
Data Alignment
Perform logical operations (raster ops)
The rectangular block of data does not change as it is transferred between System Memory locations.
Data to be transferred can consist of regions of System Memory, patterns, or solid color fills. A pattern
will always be 8x8 pixels wide and may be 8-bits, 16-bits, or 32-bits per pixel.
The GMCH BLT engine has the ability to expand monochrome data into a color depth of 8-bits, 16-bits,
or 32-bits. BLTs can be either opaque or transparent. Opaque transfers, move the data specified to the
destination. Transparent transfers compare destination color to source color and write according to the
mode of transparency selected.
Data is horizontally and vertically aligned at the destination. If the destination for the BLT overlaps with
the source System Memory location, the GMCH can specify which area in System Memory to begin the
BLT transfer. Hardware is included for all 256 raster operations (Source, Pattern, and Destination)
defined by Microsoft, including transparent BLT.
The GMCH has instructions to invoke BLT operations, permitting software to set up instruction buffers
and use batch processing as described in the Instruction Processing Section. The GMCH can perform
hardware clipping during BLTs.
Alpha Stretch BLT
The 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 System Memory into a larger or
smaller region using replication and interpolation. The stretch BLT function also provides format
conversion and data alignment.
134
Intel^® 852GM/852GMV Chipset GMCH Datasheet