MB86296 Datasheet, PDF (122/352 Pages) Fujitsu Component Limited. – PCI Graphics Controller Specification

FUJITSU LIMITED PRELIMINARY AND CONFIDENTIAL
10.5 Rendering
10.5.1 Tiling
Tiling reads the pixel color from the correlated tiling pattern and maps it onto the polygon. The tiling
determines the pixel on the pattern read by pixel coordinates to be drawn, irrespective of position and
size of primitive. Since the tiling pattern is stored in the texture memory, this function and texture
mapping cannot be used at the same time. Also, the tiling pattern size is limited to within 64 × 64
pixels. (at 16-bit color)
Example of Tiling
10.5.2 Alpha blending
Alpha blending blends the drawn in frame buffer to-be-drawn pixel or pixel already according to the
alpha value set in the alpha register. This function cannot be used simultaneously with logic operation
drawing. It can be used only when the direct color mode (16 bits/pixel) is used. The blended color C
is calculated as shown below when the color of the pixel to be drawn is C_P, the color of frame buffer is
C_F, and the alpha value is A:
C = C_P × A + (1-A) × C_F
The alpha value is specified as 8-bit data. 00h means alpha value 0% and FFh means alpha value
100%. When the texture mapping function is enabled, the following blending modes can be selected:
Normal
Blends post texture mapping color with frame buffer color
Stencil
Uses MSB of texel color for ON/OFF control:
MSB = 1: Texel color
MSB = 0: Frame buffer color
Stencil alpha
Uses MSB of texel color for α/OFF control:
MSB = 1: Alpha blend texel color and current frame buffer color
MSB = 0: Frame buffer color
Note: MSB of frame buffer is drawn MSB of texel in both stencil and stencil alpha mode.
Therefore in case MSB of texel is MSB=0, a color of frame buffer is frame buffer, but MSB of frame
buffer is set to 0.
MB86296S<Coral-PA>
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Specification Manual Rev0.1