Intel 815 Manuel D’Utilisation
Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
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13.27. GFXRENDERSTATE_PROVOKING_VTX_PIXELIZATION
_RULE
The provoking vertex state variables provide the flexibility of selecting the flat-shaded vertex for the first
triangle/line of a primitive packet. The subsequent flat-shaded vertices are in incrementing order, except
in the case of triangle fans with common flat shaded vertex. Separate State variables are provided for
triangles and lines. The following tables show the sequence of flat-shaded vertices for triangles and lines.
triangle/line of a primitive packet. The subsequent flat-shaded vertices are in incrementing order, except
in the case of triangle fans with common flat shaded vertex. Separate State variables are provided for
triangles and lines. The following tables show the sequence of flat-shaded vertices for triangles and lines.
Primitive Type
Triangle Strip/List
Flat Shading SV
Triangle Fan
Flat Shading SV
Line Strip/List
Flat Shading SV
Flat Shaded
Vertex Sequence
Triangle/Rectangle List
00
XX
XX
0, 3, 6, 9, 12 ....
01
XX
XX
1, 4, 7, 10, 13 ...
10
XX
XX
2, 5, 8, 11, 14 ...
Triangle Strip/Triangle
Strip Reverse Winding
order
Strip Reverse Winding
order
00
XX
XX
0, 1, 2, 3, 4 .. ....
01
XX
XX
1, 2, 3, 4, 5. .. ....
10
XX
XX
2, 3, 4, 5, 6 .. ....
Triangle Fan
XX
00
XX
0, 0,0,0,0,0 .. ....
“
XX
01
XX
1, 2, 3, 4, 5. .. ....
“
XX
10
XX
2, 3, 4, 5, 6 .. ....
Polygon(Triangle Fan
With Common Flat
Shaded Vertex)
With Common Flat
Shaded Vertex)
XX XX XX
0,0,0,0,0,0
....
Line List
XX
XX
X0
0, 2, 4, 6, 8 ....
XX
XX
X1
1, 3, 5, 7, 9 ...
Line Strip
XX
XX
X0
0, 1, 2, 3, 4 .. ....
XX
XX
X1
1, 2, 3, 4, 5. .. ....
The Pixelization Rule state-variable sets up the hardware to follow correct pixelization rules. It should be
set in Render Mode (i.e., for GFXPrimitive packet). The Small Triangle Filter Enable, enables filtering
of small triangles. (Small Triangles are defined as triangles which do not light any pixels). It should be
set only in Render Mode when Pixelization Rule is enabled, and the Horizontal & Vertical Bias Values
are equal and are programmed to either 1000 or 0000. If other bias values are used then the results may
be unpredictable. (The Horizontal & Vertical Bias values are programmed in the
GFXRENDERSTATE_DEST_BUFFER_VARIABLES packet). The following table summarizes
acceptable values of these SVs:
set in Render Mode (i.e., for GFXPrimitive packet). The Small Triangle Filter Enable, enables filtering
of small triangles. (Small Triangles are defined as triangles which do not light any pixels). It should be
set only in Render Mode when Pixelization Rule is enabled, and the Horizontal & Vertical Bias Values
are equal and are programmed to either 1000 or 0000. If other bias values are used then the results may
be unpredictable. (The Horizontal & Vertical Bias values are programmed in the
GFXRENDERSTATE_DEST_BUFFER_VARIABLES packet). The following table summarizes
acceptable values of these SVs:
Packet
Horizontal Bias
Vertical Bias
Pixelization Rule
Small Triangle Filter
GFXPRIMITIVE 0000 0000
1
1
GFXPRIMITIVE 1000 1000
1
1
GFXPRIMITIVE XXXX XXXX 1
0
GFXPRIMITIVE XXXX XXXX 0
0
GFXBLOCK XXXX
XXXX 0
0