SH7265 Datasheet, PDF (1535/2024 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

Section 28 2D Graphics Engine (2DG)
• Color gradation processing example (2)
The text below describes the processing where data in a specified area from the α font region and
data from a specified area on the output plane is entered into the 2DG, a color gradation
processing is performed, and the results are written back to the specified area on the output plane:
Blit mode setting: Blit mode (GR_BLTMODE register, BTYPE bits = 00)
Blending operation: With blending (GR_BLTPLY register, SB_STEN = 1 and SA_STEN bit = 1)
Blit (With blending)
The DMAC controlled by the CPU issues the
addresses of the both memories and performs
a memory-to-memory transfer.
DMAC3
Image plane in the SDRAM
Plane 1 (α value only)
04FFF40
004F400
004F400
DMAC4
Input image
04FFF40
004F400
004F400
Input image
Number of pixels Nb
Color value = Ca
α value = αa
DMAC2
A
A
Plane 2 (αRGB)
Number of pixels = Nb
α value = αb
SB
buffer
SA
buffer
DC
buffer
Number of pixels = Nb
Color value = Cout
α value = αout
Sets the number of pixels (Nb) to be transferred to the DC buffer. (By setting the GR_DCSET register)
Sets the number of pixels (Nb) to be transferred to the SA/SB buffers. (By setting the GR_SABSET register)
Sets blitter operating mode. (By setting the BTYPE bits of the GR_BLTMODE register)
Sets the SB output data mode. (By setting the SBSEL bits of the GR_BLTMODE register)
Sets the SB image format. (By setting the SB_FMT bits of the SB_FMT register)
Sets the blending coefficient value. (By setting the FBFA bits of the GR_BRD1CNT register)
GALFA = (The value set by user)
Resizing (Set by user)
Executes the processing. (By setting 11 in the GR_BLTPLY register)
Procedure
Input αb
↓
Input pixel (α color expansion)
= αb & (settings of the GR_BRDCOL
(RGB = red in the example))
↓
Weighted multiplication
(weighing each component of RGB by α value)
Cb1 = (αb × R, αb × G, αb × B)
αb = αb
↓
For example, when FBFA = 10
for blending of 2 planes,
Cout = FbCb1 + FaCa
= αbCb1 + (1 - αb) Ca
Aout = αb
Data output to the DC buffe
2DG
Figure 28.32 Example of Color Gradation Processing (2)
Rev. 1.00 Mar. 14, 2008 Page 1499 of 1984
REJ09B0351-0100