Commodore 64 Uživatelský manuál stáhnout pdf (Strana 44)

256 (on the left side of the screen), then the X MSB of that sprite must

be 0 (turned OFF). Bits 0 to 7 of the X MSB register correspond to sprites

o to 7, respectively.

The following program moves a sprite across the screen:

EXAMPLE:

--IDIIiI"

10 PF.:It-IT"::T'-

20 F'OKE2040.13

30 FORI=0T062:POKE832+I.129:NEXT

40 ..,.=5:324:3

50 POKE'.'!+21,. 1

6121POKE"'!+3S<..1

70 POKEV+ 1 " 1121(1

8121FOF(J=!3TOcH7

90 HX=INTeJ/256)'LX=J-256*HX

100 POKEV.LX:POKEV+16.HX:NE~T

When moving expanded sprites onto the left side of the screen in the

X direction, you have to start the sprite OFF SCREENon the RIGHTSIDE.

This

is because an expanded sprite is larger than the amount of space

available on the left side of the screen.

EXAMPLE:

,ABI"

1121pF.:nn":J"

2(1 F'OKE2!~140.

FORI=0T062:POKE832+I.129:NEXT

4121 \.':=::5::':248

50 POKE','!+21" 1

POKEV+39.1:POKEV+23.1:POKEV+29.1

70 POKE'.,!+1 . 10(~

:3121J~48:::

90 HX=INTeJ/256):LX=J-256*HX

100 POKEV,LX:POKEV+16.HX

110 J=J+l:IFJ)511THENJ=0

120 IFJ)4880RJ<348GOT090

The charts in Figure 3-3 explain sprite positioning.

By using these values, you can position each sprite anywhere. By mov-

ing the sprite a single dot position at a time, very smooth movement is

easy to achieve.

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Commodore 64 Uživatelský manuál Strana 44