SH7205 Datasheet, PDF (1454/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 26 2D Graphics Engine (2DG)
• Chromakey processing example (1)
Blit mode setting:
Fill mode (GR_BLTMODE register, BTYPE bits = 10)
Chromakey type selection: Chromakey replacement (GR_BLTMODE register, CRKEY bits = 01)
Operation is the same as when the FBFA bit in the GR_BRD1CNT
register (blending coefficient selection) had been set to 01. However,
the value of the FBFA bits in the GR_BRD1CNT register does not
change.
SB output data selection: SB data selection = (GR_BLTMODE register, SBSEL bits = 01)
Target color setting:
Setting for green as the target color in the GR_DETCOL register
Replacement color setting: Setting for blue as the replacement color in the GR_BRDCOL register
Chromakey processing (Without blending)
The same operation as the
FBFA bit in the GR_BRDICNT register = 01
Blending processor (Without blending)
The pixels of the specified color in the SB area
are replaced with the replacement color
(Fa = 1, Fb = 0), and the other pixels are
output unchanged (Fa= 0, Fb = 1).
When green is target color
(as the specified color)
Green area
Yellow area
When blue is the replacement color
When color value (Cc, αc)
is set to blue
in the GR_BRDCOL register
(Color value is constantly input.)
Chromakey target color
processing block
Input B buffer
Specified color area
(Data of the specified color is added.)
Yellow area
Fa = 0 and
Fb = 1 are set
for this area.
Fa
Fb
A color specified by the color
value (α value) in the register
This area
remains yellow
Figure 26.28 Example of Chromakey Processing (1)
Rev. 1.00 Mar. 25, 2008 Page 1422 of 1868
REJ09B0372-0100