Commodore 64 Manual de usuario descargar pdf (Pagina 33)

SPRITES

A SPRITE is a special type of user definable character which can be

displayed anywhere on the screen. Sprites are maintained directly by

the VIC-II chip. And all you have to do is tell a sprite "what to look like,"

"what color to be," and "where to appear." The V/C-II chip will do the

rest! Sprites can be any of the 16 colors available.

Sprites can be used with ANY of the other graphics modes, bit

":lapped, character, multi-color, etc., and they'll keep their shape in all

of them. The sprite carries its own color definition, its own mode (HI-RES

or multi-colored), and its own shape.

Up to 8 sprites at a time can be maintained by the VIC-II chip auto-

matically. More sprites can be displayed using RASTER INTERRUPT

techniques.

The features of SPRITESinclude:

1) 24 horizontal dot by 21 vertical dot size.

2) Individual color control for each sprite.

3) Sprite multi-color mode.

4) Magnification (2X) in horizontal, vertical, or both directions.

5) Selectable sprite to background priority.

6) Fixed sprite to sprite priorities.

7) Sprite to sprite collision detection.

8) Sprite to background collision detection.

These special sprite abilities make it simple to program many arcade

style games. Because the sprites are maintained by hardware, it is even

possible to write a good quality game in BASIC!

Th( r.3 are 8 sprites supported directly by the VIC-II chip. They are

numbered from 0 to 7. Each of the sprites has it own definition location,

position registers and color register, and has its own bits for enable and

collision detection.

DEFINING A SPRITE

Sprites are defined like programmable characters are defined. How-

ever, since the size of the sprite is larger, more bytes are needed. A

sprite is 24 by 21 dots, or 504 dots. This works out to 63 bytes (504/8

PROGRAMMINGGRAPHICS 131

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Commodore 64 Manual de usuario Pagina 33