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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 8 Window
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VDP2 User's Manual/Chapter 8 Window

■8.2 Window processing

There are three types of window processing:

  1. Transparency processing window
  2. Rotation parameter window
  3. Color calculation window

A transparent processing window is a window that forcibly makes the specified window effective area transparent, and can be used for each screen.

The rotation parameter window is a window that specifies whether to display the image obtained by rotation parameter A or the image obtained by rotation parameter B when displaying the RBG0 screen. The image obtained using rotation parameter B is displayed in the specified window effective area, and the image obtained using rotation parameter A is displayed outside the window effective area.

The color calculation window is a window that prevents color calculations from being performed in the specified window effective area, and is valid for screens that use the color calculation function.

Window processing is shown in Figure 8.7.

Figure 8.7.1 Window processing 1

Figure 8.7.2 Window processing 2

Figure 8.7.3 Window processing 3

●Window control register

Window control registers specify how windows are used for each screen. This is a 16-bit write-only register located at addresses 1800D0H to 1800D6H. The value is cleared to 0 after power-on or reset, so be sure to set it.

WCTLA 1800D0H
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 N1LOG
 -
 N1SWE
 N1SWA
 N1W1E
 N1W1A
 N1W0E
 N1W0A

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 N0LOG
 -
 N0SWE
 N0SWA
 N0W1E
 N0W1A
 N0W0E
 N0W0A

WCTLB 1800D2H
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 N3LOG
 -
 N3SWE
 N3SWA
 N3W1E
 N3W1A
 N3W0E
 N3W0A

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 N2LOG
 -
 N2SWE
 N2SWA
 N2W1E
 N2W1A
 N2W0E
 N2W0A

WCTLC 1800D4H
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 SPLOG
 -
 SPSWE
 SPSWA
 SPW1E
 SPW1A
 SPW0E
 SPW0A

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 R0LOG
 -
 R0SWE
 R0SWA
 R0W1E
 R0W1A
 R0W0E
 R0W0A

WCTLD 1800D6H
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 CCLOG
 -
 CCSWE
 CCSWA
 CCW1E
 CCW1A
 CCW0E
 CCW0A

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 RPLOG
 -
 RPSWE
 RPSWA
 RPW1E
 RPW1A
 RPW0E
 RPW0A

　
Window logic bit : Logic bit
(N0LOG, N1LOG, N2LOG, N3LOG, R0LOG, SPLOG, RPLOG, CCLOG)
Specifies the window stacking method used for each screen.

N0LOG 1800D0H bit 7 For NBG0 (or for RBG1) in the transparency processing window
N1LOG 1800D0H bit 15 For NBG1 (or for EXBG) in the transparency processing window
N2LOG 1800D2H bit 7 For NBG2 of transparent processing window
N3LOG 1800D2H bit 15 For NBG3 of transparent processing window
R0LOG 1800D4H bit 7 For RBG0 of transparency processing window
SPLOG 1800D4H bit 15 For sprites in the transparency processing window
RPLOG 1800D6H bit 7 For rotation parameter window
CCLOG 1800D6H bit 15 For color calculation window

xxLOG superposition logic
0 OR
1 AND
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, RP, or CC.

If the window enable bits of W0, W1, and SW are all 0, setting this bit to 0 will make the entire screen no longer a window valid area, and setting this bit to 1 will make the entire screen a window valid area.

　

Window enable bit (for W0) : W0 enable bit
(N0W0E, N1W0E, N2W0E, N3W0E, R0W0E, SPW0E, RPW0E, CCW0E)
Specify whether to use normal window W0 for each screen.

N0W0E 1800D0H bit 1 For NBG0 (or for RBG1) in the transparency processing window
N1W0E 1800D0H bit 9 For NBG1 (or for EXBG) in the transparency processing window
N2W0E 1800D2H bit 1 For NBG2 of transparent processing window
N3W0E 1800D2H bit 9 For NBG3 of transparent processing window
R0W0E 1800D4H bit 1 For RBG0 of transparency processing window
SPW0E 1800D4H bit 9 For sprites in the transparency processing window
RPW0E 1800D6H bit 1 For rotation parameter window
CCW0E 1800D6H bit 9 For color calculation window

xxW0E process
0 Don't use W0 window
1 Use W0 window
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, RP, or CC.

Window enable bit (for W1) : W1 enable bit
(N0W1E, N1W1E, N2W1E, N3W1E, R0W1E, SPW1E, RPW1E, CCW1E)
Specify whether to use normal window W1 for each screen.

N0W1E 1800D0H bit 3 For NBG0 (or for RBG1) in the transparency processing window
N1W1E 1800D0H bit 11 For NBG1 (or for EXBG) in the transparency processing window
N2W1E 1800D2H bit 3 For NBG2 of transparent processing window
N3W1E 1800D2H bit 11 For NBG3 of transparent processing window
R0W1E 1800D4H bit 3 For RBG0 of transparency processing window
SPW1E 1800D4H bit 11 For sprites in the transparency processing window
RPW1E 1800D6H bit 3 For rotation parameter window
CCW1E 1800D6H bit 11 For color calculation window

xxW1E process
0 Don't use W1 window
1 Use W1 window
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, RP, or CC.

Window enable bit (for SW) : SW enable bit
(N0SWE, N1SW, N2SWE, N3SWE, R0SWE, SPSWE, CCSWE)
Specify whether to use sprite window SW for each screen.

N0SWE 1800D0H bit 5 For NBG0 (or for RBG1) in the transparency processing window
N1SWE 1800D0H bit 13 For NBG1 (or for EXBG) in the transparency processing window
N2SWE 1800D2H bit 5 For NBG2 of transparent processing window
N3SWE 1800D2H bit 13 For NBG3 of transparent processing window
R0SWE 1800D4H bit 5 For RBG0 of transparency processing window
SPSWE 1800D4H bit 13 For sprites in the transparency processing window
CCSWE 1800D6H bit 13 For color calculation window

xxSWE process
0 Do not use SW window
1 Use SW window
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, or CC.

When using the sprite window, set the sprite window enable bit (SPWINEN) in the sprite control register to 1.

Window area bit (for W0) : W0 area bit
(N0W0A, N1W0A, N2W0A, N3W0A, R0W0A, SPW0A, RPW0A, CCW0A)
Specify which area is the valid area of normal window W0 to be used for each screen.

N0W0A 1800D0H bit 0 For NBG0 (or for RBG1) in the transparency processing window
N1W0A 1800D0H bit 8 For NBG1 (or for EXBG) in the transparency processing window
N2W0A 1800D2H bit 0 For NBG2 of transparent processing window
N3W0A 1800D2H bit 8 For NBG3 of transparent processing window
R0W0A 1800D4H bit 0 For RBG0 of transparency processing window
SPW0A 1800D4H bit 8 For sprites in the transparency processing window
RPW0A 1800D6H bit 0 For rotation parameter window
CCW0A 1800D6H bit 8 For color calculation window

xxW0A process
0 Enable inside W0 window
1 Enable outside W0 window
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, RP, or CC.

Window area bit (for W1) : W1 area bit
(N0W1A, N1W1A, N2W1A, N3W1A, R0W1A, SPW1A, RPW1A, CCW1A)
Specify the effective area of normal window W1 to be used for each screen.

N0W1A 1800D0H bit 2 For NBG0 (or for RBG1) in the transparency processing window
N1W1A 1800D0H bit 10 For NBG1 (or for EXBG) in the transparency processing window
N2W1A 1800D2H bit 2 For NBG2 of transparent processing window
N3W1A 1800D2H bit 10 For NBG3 of transparent processing window
R0W1A 1800D4H bit 2 For RBG0 of transparency processing window
SPW1A 1800D4H bit 10 For sprites in the transparency processing window
RPW1A 1800D6H bit 2 For rotation parameter window
CCW1A 1800D6H bit 10 For color calculation window

xxW1A process
0 Enable inside W1 window
1 Enable W1 outside window
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, RP, or CC.

Window area bit (for SW) : SW area bit
(N0SWA, N1SWA, N2SWA, N3SWA, R0SWA, SPSWA, CCSWA)
Specify the effective area of the sprite window SW to be used for each screen.

N0SWA 1800D0H bit 4 For NBG0 (or for RBG1) in the transparency processing window
N1SWA 1800D0H bit 12 For NBG1 (or for EXBG) in the transparency processing window
N2SWA 1800D2H bit 4 For NBG2 of transparent processing window
N3SWA 1800D2H bit 12 For NBG3 of transparent processing window
R0SWA 1800D4H bit 4 For RBG0 of transparency processing window
SPSWA 1800D4H bit 12 For sprites in the transparency processing window
CCSWA 1800D6H bit 12 For color calculation window

xxSWA process
0 Enable inside SW window
1 Enable outside SW window
[Note] xx in the bit name is N0, N1, N2, N3, R0, SP, or CC.

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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 8 Window
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