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Routines |
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Used by the routines at UpdateSpore and UpdateVillageItem.
Chooses a new random velocity along both axes for an object when the timer has run out (the lowest six bits of the direction and timer) or when the object is not moving. The velocity along each axis is an even number, chosen from the random seeds. A new timer is set from the memory refresh register.
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| ChooseRandomVelocity | DDCF | DEC (IX+$06) | Count down the timer, and jump to ChooseRandomVelocity_Choose if it has run out. | |||||||
| DDD2 | LD A,(IX+$06) | |||||||||
| DDD5 | AND $3F | |||||||||
| DDD7 | JR Z,ChooseRandomVelocity_Choose | |||||||||
| DDD9 | LD A,(IX+$0A) | Return if the object is moving. | ||||||||
| DDDC | OR (IX+$0B) | |||||||||
| DDDF | RET NZ | |||||||||
| ChooseRandomVelocity_Choose | DDE0 | LD A,($BBAA) | Choose the velocity along the X axis from the first random seed. | |||||||
| DDE3 | LD C,A | |||||||||
| DDE4 | CALL ChooseVelocity | |||||||||
| DDE7 | LD (IX+$0A),A | |||||||||
| DDEA | LD A,($BBAB) | Choose the velocity along the Y axis from the second random seed. | ||||||||
| DDED | LD C,A | |||||||||
| DDEE | CALL ChooseVelocity | |||||||||
| DDF1 | LD (IX+$0B),A | |||||||||
| DDF4 | LD A,R | Set a random timer. | ||||||||
| DDF6 | AND $3F | |||||||||
| DDF8 | LD (IX+$06),A | |||||||||
| DDFB | RET | Return. | ||||||||
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