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

Texels

Blending Stages

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 F0–F3. 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 (ME0 – ME3) 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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F0

 

F1

F2

F3

 

 

 

 

 

 

 

 

 

0

Arbitrary Attribute

8

Alpha, Intensity, Luminance,

I

 

I

I

I

 

 

 

Chromanance, etc. (I: 8)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

Alpha Attribute

16

Alpha and Luminance,

Y

 

Y

Y

A

 

 

 

Chromanance, etc. (AY: 88)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.

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Intel 815 manual Gfxrenderstatemapinfo