MB86293 Datasheet, PDF (86/285 Pages) Fujitsu Component Limited. – Grraphiics Conttrrollllerr Speciiffiicattiions

FUJITSU LIMITED
PRELIMINARY and CONFIDENTIAL
8.5 R e n d e r i n g
8.5.1 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.
The tiling pattern size is limited to within 64 × 64 pixels. (at 16-bit color)
8.5.2 Alpha blending
Example of Tiling
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 texcel color for ON/OFF control:
MSB = 1: Texcel color
MSB = 0: Frame buffer color
Stencil alpha
Uses MSB of texcel color for α/OFF control:
MSB = 1: Alpha blend texcel color and current frame buffer color
MSB = 0: Frame buffer color
Note: MSB of frame buffer is drawn MSB of texcel in both stencil and stencil alpha mode.
Therefore in case MSB of texcel is MSB=0, a color of frame buffer is frame buffer, but MSB of
frame buffer is set to 0.
MB86293 CORAL_LQ
Graphics Controller
86
Specifications Rev. 1.1