User's Manual

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
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13.7. GFXRENDERSTATE_MAP_INFO
The Mapping Engine is capable of fetching texels from at most two maps per pixel. This instruction
specifies the attributes relating to the location and format of the map. Two different texels can be fetched
from the same map.
Figure 33. State Variable Relationships
Coordinate Sets Map Information
Blending Stages
Texels
Table 14 identifies four classes of surface formats for the supported maps in the GC. The various
attributes of the texels/pixels are placed on 4 abstract channels named F
0
–F
3
. These channels can be
switched into 4 output channels, which are delivered by the Mapping Engine to the Color Calculator. The
switching of these channels (ME
0
– ME
3
) is controlled by the Output Channel Selection field described
below.
Table 14. Summary of Source Surface Formats with Filter Output Channel Mappings
# Source Format Bpt Attribute Types and Formats Filter Channels
F
0
F
1
F
2
F
3
0 Arbitrary Attribute 8 Alpha, Intensity, Luminance,
Chromanance, etc. (I: 8)
I I I I
1 Alpha Attribute 16 Alpha and Luminance,
Chromanance, etc. (AY: 88)
Y Y Y A
2 Alpha Red Grn Blue 16 ARGB: 0565/1555/4444 R G B A
3 4:2:2 YCrCb 4:2:2 Cr Y Cb 1’s
Certain memory tiling properties are supported directly by this instruction. This functionality is provided
primarily for discrete graphics devices and for surfaces that do not need transparent processor access
(such as optimized texture maps). Bits [31:26] of the Base Address are used to identify memory access
from discrete graphics devices, which are intended to bypass the Graphics Translation Table (GTT). The
following table identifies which fields are used (
✔) or ignored (⊗) for various permutations. The first two
columns identify which cases (either discrete or integrated) graphics devices use. The Pitch field must be
specified in all cases.