<4/86> VDP2 User's Manual / 1.4 Priority Function

★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 1 Functions of VDP2

▲ Back ｜ Forward ▼

VDP2 User's Manual / Chapter

■ 1.4 Priority function

There are four types of VDP2 priority functions: priority function, color calculation function, color offset function, and shadow function.

● Priority function

The display priority of sprites and scroll screens is determined by the size of a 3-bit value called the priority number.
You can set up to eight values for the sprite priority number, one of which is specified on a character-by-character basis.
The priority number of the scroll screen is usually specified in units of faces. You can also change by character or dot by using the special priority function.

● Color calculation function

The color calculation function is a function that adds color data from multiple screens to create an effect that allows the back screen to be seen through the front screen. Normally, it is performed on two screens, the top image and the second image, but it can also be performed on up to four screens by using the extended color calculation function.
Whether or not to perform color calculation is usually specified on a face-by-face basis. Sprites can also be specified on a character-by-character basis by setting sprite color calculation conditions. You can also specify the scroll screen in character units or dot units by using the special color calculation function.
The color calculation ratio of the top image and the second image can be specified from 32 levels. Sprites allow you to set up to eight color percentages, one of which is specified on a character-by-character basis. In addition, the scroll screen is specified in units of faces.
You can use the blur calculation function to display one specified screen with a horizontal blur.

● Color offset function

The color offset function is a function that adds (subtracts) an offset value to the color data on the screen and displays it, and is used for fade-in and fade-out. You can specify whether to use the color offset function on a face-by-face basis.
Up to two color offset values can be set for each RGB, and which one to use can be specified for each surface.

● Shadow function

The shadow function is a function that casts a shadow in the shape of a sprite character on each screen.
There are two types of shadow sprites, normal shadows and MSB shadows, depending on the data. Normal shadows can only cast shadows on the scroll screen. MSB shadows can cast shadows on sprites as well as scroll screens.

▲ Back ｜ Forward ▼

★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 1 Functions of VDP2