910GL datasheet(237/426 Pages) INTEL

237 / 426 page

Functional Description

Datasheet

237

12.6.2.2

Pixel Accurate “Fast” Scissoring and Clipping Operation

The GMCH supports 2D clipping to a scissor rectangle within the drawing window. Objects are

clipped to the scissor rectangle, avoiding processing pixels that fall outside the rectangle. The

GMCH’s clipping and scissoring in hardware reduce the need for software to clip objects, and

thus improve performance. During the setup stage, GMCH clips objects to the scissor window.

A scissor rectangle accelerates the clipping process by allowing the driver to clip to a bigger

region than the hardware renders to. The scissor rectangle needs to be pixel accurate, and

independent of line and point width. The GMCH will support a single scissor box rectangle that

can be enabled or disabled. The rectangle is defined as an Inclusive box. Inclusive is defined as

“draw the pixel if it is inside the scissor rectangle”.

12.6.2.3

Depth Bias

The GMCH supports source Depth Biasing in the Setup Engine. 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. If two polygons are to be rendered that are coplanar, due to the inherent

precision differences induced by unique x, y and z values, there is no guarantee which polygon

will be closer or farther. By using Depth Bias, it is possible to offset the destination z value

(compare value) before comparing with the new z value.

12.6.2.4

Backface Culling

As part of the setup, 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.

12.6.2.5

Scan Converter

Working on a per-polygon basis, the Scan Converter uses the vertex and edge information is used

to identify all pixels affected by features being rendered.

12.6.2.6

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 will be used. Pixel rasterization rule on rectangle primitive is also

supported using the top-left fill convention.

12.6.2.7

2D Functionality

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 memory into a larger or

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

conversion and data alignment.

910GL датащи(PDF) 237 Page - Intel Corporation

910GL датащи(HTML) 237 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

датащи скачать

ссылки URL