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Routines |
| Prev: D730 | Up: Map | Next: D7F3 |
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Checking if:
Only one creature missile and one Maroc-fired missile (i.e. 2 missiles total) can be on-screen at any one time.
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| D794 | LD A,$00 | |||
| D796 | LD ($EAD4),A | Indicates screen/viewport - 0 = current screen/viewport | ||
| D799 | LD A,$05 | |||
| D79B | LD ($EB9A),A | Pre-set the missile type. 5 = missile fired at Maroc by creatures (rather than vice versa) | ||
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Check if a missile/bolt has been set up (and if not, set it up):
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| D79E | LD A,($EB93) | Get missile number (table at 6CDC) | ||
| D7A1 | CP $00 | |||
| D7A3 | JR Z,$D7AD | 0 = no missile present | ||
| D7A5 | CALL $DB1F | If not zero, set up this missile set data | ||
| D7A8 | LD A,$00 | Missile has now been set up and stored in the data sets at 7C00, so can now set the missile number to zero | ||
| D7AA | LD ($EB93),A | |||
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Check if Maroc has launched a missile spell:
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| D7AD | LD A,($EC98) | This byte contains an 'action' byte set when Maroc presses fire after aiming his missile-based spell cursor, and contains values for the different missile spells | ||
| D7B0 | CP $00 | If zero, Maroc hasn't fired a missile spell - skip next section | ||
| D7B2 | JR Z,$D7F3 | |||
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Maroc has launched a missile-type spell. Calculate trajectory of missile:
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| D7B4 | LD A,($EB92) | Flag indicating if Maroc has fired a missile (1 = missile fired, 0 = no missile) | ||
| D7B7 | CP $00 | |||
| D7B9 | JR NZ,$D7EE | If there's already one, skip the setup | ||
| D7BB | INC A | Increment so the flag = 1 (missile fired) | ||
| D7BC | LD ($EB92),A | ...and re-store. | ||
| D7BF | LD A,$00 | Precision/overflow byte for horizontal/vertical item position (reset both to 0) | ||
| D7C1 | LD ($EB94),A | |||
| D7C4 | LD ($EB96),A | |||
| D7C7 | LD A,($EAC0) | Maroc's horizontal (X-axis) screen position | ||
| D7CA | LD ($EB95),A | Set this as the missile's horizontal (X) co-ordinate origin | ||
| D7CD | LD A,($EAC1) | Maroc's vertical (Y-axis) screen position | ||
| D7D0 | LD ($EB97),A | Set this as the missile's vertical (Y) co-ordinate origin | ||
| D7D3 | LD A,($EAFF) | Get the vertical (Y) pixel position of the aiming cursor | ||
| D7D6 | LD ($EB99),A | Store as the target vertical pixel (Y) co-ordinate for the missile | ||
| D7D9 | LD A,($EB00) | Get the horizontal (X) pixel position of the aiming cursor | ||
| D7DC | RRA | This value is currently in pixel steps, so divide by 4 to get into 4-pixel (half-character steps) | ||
| D7DD | RRA | |||
| D7DE | AND $3F | Filter out any unnecessary carry bits | ||
| D7E0 | LD ($EB98),A | ...and store | ||
| D7E3 | LD A,$08 | Item/missile type = 8 (missile fired by Maroc) | ||
| D7E5 | LD ($EB9A),A | Store in missile data set | ||
| D7E8 | LD A,($EC98) | |||
| D7EB | CALL $DB1F | Set up missile data | ||
| D7EE | LD A,$00 | This is the action byte set when Maroc presses fire after aiming his missile-based spell cursor - contains values for the different missile spells | ||
| D7F0 | LD ($EC98),A | Now that the missile has been initialized, set this flag to 0. | ||
| Prev: D730 | Up: Map | Next: D7F3 |