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PROGRAMMING SPRITES-ANOTHER LOOK

For those of you having trouble with graphics, this section has been

designed as a more elementary tutorial approach to sprites.

MAKING SPRITES IN BASIC-A SHORT PROGRAM

There are at least three different BASIC programming techniques

which let you create graphic images and cartoon animations on the

Commodore 64. You can use the computer's built-in graphics character

set (see Page 376). You can program your own characters (see Page

108) or . . . best of all . . . you can use the computer's built-in "sprite

graphics." To illustrate how easy it is, here's one of the shortest

spritemaking programs you can write in BASIC:

5(1

AllDramE

PR ItH "6' -

POKE2iZ14iZ1.. 13

FOF:::;=8:32TO::::32+62 : POKES, 255 : t'~EXT

11,"==5:3248

POKEV+21,l

POKE' +:39.. 1

POKE'v'.'24

POKE + 1 .' 100

This program includes the key "ingredients" you need to create any

sprite. The POKE numbers come from the SPRITEMAKINGCHART on

Page 176. This program defines the first sprite

. . . sprite 0 . . . as a

solid white square on the screen. Here's a line-by-line explanation of the

program:

LINE 10 clears the screen.

LINE 20 sets the "sprite pointer" to where the Commodore 64 will

read its sprite data from. Sprite 0 is set at 2040, sprite 1 at 2041, sprite

2 at 2042, and so on up to sprite 7 at 2047. You can set all 8 sprite

pointers to 13 by using this line in place of line 20:

20 FOR SP=2040T02047:POKE SP,13:NEXT SP

LINE

30 puts the first sprite (sprite 0) into 63 bytes of the Commodore

64's RAM memory starting at location 832 (each sprite requires 63 bytes

of memory). The first sprite (sprite 0) is "addressed" at memory locations

832 to 894.

PROGRAMMINGGRAPHICS 153

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Commodore 64 Manual do Utilizador Página 55