Japanese
★ HARDWARE Manual ★ VDP1 User's Manual
▲ Back ｜ Forward ▼
VDP1 User's Manual/Chapter 6 Command Table

■Transparent pixels disabled

Transparent pixel disable bit: see-through pixel disable (SPD), bit 6
Specifies whether to disable transparent pixels in the character pattern. When set to 0, transparent pixels are enabled; when set to 1, transparent pixels are disabled.
The transparent pixel disable bit is only valid for drawing sprites with character patterns. This bit must be set to 1 for polygons, polylines, and lines.
When transparent pixels are enabled (SPD=0), transparent color codes in character patterns become transparent pixels and are not drawn. When end codes are disabled (SPD=1), transparent color codes are treated like any other color code.
Please note that when transparent pixels are enabled (SPD=0), the number of available colors will be reduced by one. For example, when ECD=0, SPD=0 and color mode=0, only 14 colors can be displayed.

 SPD
 Handling transparent pixels
 0
 Transparent pixel enabled, does not draw transparent color code,
 Transparent color code becomes transparent
 1
 Transparent pixels disabled, transparent color codes are not processed,
 Draw with the color according to the code

The relationship between color mode and transparent color code is as follows. The number of bits of the transparent color code differs depending on the color mode.

 color mode
 transparent color code
 0
 16 colors (color bank mode)
 0H (4 bits)
 1
 16 colors (lookup table mode)
 0H (4 bits)
 2
 64 colors (color bank mode)
 00H (8 bit)
 3
 128 colors (color bank mode)
 00H (8 bit)
 4
 256 colors (color bank mode)
 00H (8 bit)
 5
 32768 colors (RGB mode)
 0000H (16 bit)

▲ Back ｜ Forward ▼
★ HARDWARE Manual ★ VDP1 User's Manual
Copyright SEGA ENTERPRISES, LTD., 1997