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Routines |
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Used by the routine at HandlerFlame.
Starts a new direction timer for a flame (40 frames) and chooses its velocity. On every other call the velocity is random: the X velocity comes from the table at FlameVelocities and the Y velocity from the counter and the Z80 refresh register. On the other calls the flame heads towards the player (see AimFlameAtPlayer).
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| ChooseFlameDirection | 9E0E | LD (IX+$02),$40 | Set the direction timer of the flame to 40. | |||||
| 9E12 | LD A,($9693) | Fetch the low byte of the game timer from GameTimer. | ||||||
| 9E15 | AND %00000001 | Keep only bit 0. | ||||||
| 9E17 | JR NZ,AimFlameAtPlayer | Jump to AimFlameAtPlayer to aim the flame at the player if bit 0 of the pass counter is set. | ||||||
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Choose a random velocity.
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| 9E19 | LD A,($9695) | Fetch the random seed from RandomNumber. | ||||||
| 9E1C | AND %00000111 | Keep only bits 0-2. | ||||||
| 9E1E | CALL FetchFlameVelocity | Fetch a velocity from the table. | ||||||
| 9E21 | LD (IX+$06),A | Set the X velocity of the flame. | ||||||
| 9E24 | LD A,R | Fetch the Z80 refresh register as a source of randomness. | ||||||
| 9E26 | LD C,A | Stash it in C. | ||||||
| 9E27 | LD A,($9693) | Fetch the low byte of the game timer from GameTimer. | ||||||
| 9E2A | ADD A,C | Add the refresh register value. | ||||||
| 9E2B | LD (IX+$07),A | Set the Y velocity of the flame. | ||||||
| 9E2E | RET | Return. | ||||||
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