VT8601 Via, VT8601 Datasheet - Page 131

• Manufacturer Part Number: VT8601
• Description: Slot-1 / Socket-370 PCI North Bridge
• Manufacturer: Via

Specular / Fog Start Value
The specular / fog start value is used for specular shading or
fogging.
DoubleWord 0 – Start Value
Specular Parameters
Specular parameters are used for specular shading. These
parameters are not present in flat color mode and consist of
starting values incremental along the main direction ((dx, dy) =
(M1, 1)), and incremental along the X axis.
DoubleWord 0 – X-Axis Blue Gradient
DoubleWord 1 – Y-Axis Blue Gradient
DoubleWord 2 – X-Axis Green Gradient
DoubleWord 3 – Y-Axis Green Gradient
DoubleWord 4 – X-Axis Red Gradient
DoubleWord 5 – Y-Axis Red Gradient
Revision 1.3 September 8, 1999
31-24 Initial Fog Value
23-16 Initial Red Value
15-8 Initial Green Value
31-0 X-Axis Blue Gradient
31-0 Y-Axis Blue Gradient
31-0 X-Axis Green Gradient
31-0 Y-Axis Green Gradient
31-0 X-Axis Red Gradient
31-0 Y-Axis Red Gradient
7-0
7HFKQRORJLHV ,QF
Initial Fog value on main edge (left edge of trapezoid
or long edge of triangle). Unsigned integer.
Initial Red value on main edge (left edge of trapezoid
or long edge of triangle). Unsigned integer.
Initial Green value on main edge (left edge of
trapezoid or long edge of triangle). Unsigned integer.
Initial Blue Value
Initial Blue value on main edge (left edge of
trapezoid or long edge of triangle). Unsigned integer.
Gradient of Blue along the X axis over the primitive
surface. Signed 20.12 number.
Gradient of Blue along the Y axis over the primitive
surface. Signed 20.12 number.
Gradient of Green along the X axis over the primitive
surface. Signed 20.12 number.
Gradient of Green along the Y axis over the primitive
surface. Signed 20.12 number.
Gradient of Red along the X axis over the primitive
surface. Signed 20.12 number.
Gradient of Red along the Y axis over the primitive
surface. Signed 20.12 number.
:H &
:H &R R QQHFW
QQHFW
-125
Fog Parameters
Fog parameters are used for fogging. These parameters are
not present in flat color mode and consist of starting values
incremental along the X and Y axis.
DoubleWord 0 – X-Axis Fog Gradient
DoubleWord 1 – Y-Axis Fog Gradient
31-0 X-Axis Fog Gradient
31-0 Y-Axis Fog Gradient
Gradient of Fog along the X axis over the primitive
surface. Signed 20.12 number.
Gradient of Fog along the Y axis over the primitive
surface. Signed 20.12 number.
VT8601 Apollo ProMedia
3D Graphics Engine Registers