Commodore 64 Uživatelský manuál stáhnout pdf (Strana 75)

LINE 75:

IFP=193THEN

GOSUB300

UNE 80:

POKE2040,P

FORT= lT060:

LINE85:

P=P+1

IFP>194THEN

P= 192

If the sprite pointer is set to '193 (the second

sprite shape) the waveform control for the second

sound effect (Voice 2) is set to 129 and 128 per

line 300.

Sets the SPRITE POINTER to location 1-92 (re-

member P=192 in line 451 Here's where we use

the P).

A simple time delay loop which sets the speed at

.which the mouse dances. (Try a faster or slower

speed by increasing/decreasing the number t>0.)

Nowwe increase the value,of the pointer by add-

ing 1 'to the original value ofP.

We only w.ant to point the sprite YO3 memory lo-

cations. '192 points to locations 1"2288 to ,12350,

193 points to locatio'ns 12352 to 12414, and 194

points to locations 12416 to 12478. This line tells

the computer to reset P back to 192 as ,soon as P

becomes 195 so P never really becomes 195. P is

192, '193, 194 and then resets back to 192 and

the pointer winds up pointing consecutively to the

three sprite shapes in the three 64-byte groups of

memory locations containing the' DATA.

PROGRAMMING GRAPHICS 173

1 2 ... 70 71 72 73 74 75 76 77 78 79 80 81 82 83

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Commodore 64 Uživatelský manuál Strana 75