MB86296 Datasheet, PDF (24/352 Pages) Fujitsu Component Limited. – PCI Graphics Controller Specification

FUJITSU LIMITED PRELIMINARY AND CONFIDENTIAL
Alpha blending
Alpha blending blends two image colors to provide a transparent effect. CORAL supports two
types of blending; blending two different colors at drawing, and blending overlay planes at display.
Transparent color is not used for these blending options.
There are two ways of specifying alpha blending for drawing:
(1) Set a transparent coefficient to the register; the transparent coefficient is applied for
transparency processing of one plane.
(2) Set a transparent coefficient for each vertex of the plane; as with Gouraud shading, the
transparent coefficient is linear-interpolated to perform transparent processing in pixel units.
In addition to the above, the following settings can be performed at texture mapping. When the
most significant bit of each texture cell is 1, drawing or transparency can be set. When the most
significant bit of each texture cell is 0, non-drawing can be set.
Type
Drawing
Overlay display
Alpha Blending
Description
Transparent ratio set in particular register
While one primitive (polygon, pattern, etc.), being drawn,
registered transparent ratio applied
A transparent coefficient set for each vertex. A linear-
interpolated transparent coefficient applied.
This is possible only in direct color mode.
Blends top layer pixel color with lower layer pixel color
Transparent coefficient set in particular register
Registered transparent coefficient applied during one frame
scan
Gouraud Shading
Gouraud shading can be used in the direct color mode to provide 3D object real shading and color
gradation.
Gray Scale Gouraud Shading
Gray scale gouraud shading can be used in the in-direct color mode to draw a blend coefficient
layer.
MB86296S<Coral-PA>
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Specification Manual Rev0.1