SH7764 Datasheet, PDF (1129/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Saturation processing
Section 23 G2D
Pre-clipping
Pre-clipping
Pre-clipping
Z=0 ZSATVMINR
ZCLPMINR
ZCLPMAXR
Note : POLYGON4 type and CLRWC : Four vertices after coordinate transformation
BITBLT type, AAFA and AAFC : One vertex for center coordinates after coordinate transformation
(R)FTRAPC :
Four vertices of circumscribed quadrangle after coordinate transformation
(4) Perspective W Division
TX and TY after matrix operation are processed as follows, according to the affine transformation
enable bit (AFE) in the coordinate transformation control register (GTRCR).
• AFE = 0
The output X coordinate X' and output Y coordinate Y' becomes: X' = TX/WC + GTROFSX,
Y' = TY/WC + GTROFSY.
GTROFSX and GTROFSY are set in the coordinate transformation offset X register
(GTROFSX) and coordinate transformation offset Y register (GTROFSY), respectively.
GTROFSX and GTROFSY are set as 16-bit integers (two's complement).
• AFE = 1
The output X coordinate X' and output Y coordinate Y' becomes: X' = TX, Y' = TY. Z
clipping, perspective W division, and offset addition are not performed.
When AFE = 0, if the W division result TX/WC or TY/WC exceeds the corresponding range of
−H'7FFF ≤ TX/WC, TY/WC ≤ H'7FFF, saturation processing is performed. Then after adding the
offset (GTROFSX or GTROFSY), if TX/WC + GTROFSX or TY/WC + GTROFSY exceeds the
corresponding range of −H'7FFF ≤ TX/WC + GTROFSX, TY/WC + GTROFSY ≤ H'7FFF,
saturation processing is performed likewise. Even if saturation processing has been performed, the
command is continuously executed at the vertex coordinates which have been saturated.
Rev. 1.00 Nov. 22, 2007 Page 1073 of 1692
REJ09B0360-0100