| ← CEB3 | Map | D00C → |
CFB1: Bee behavior handler
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Per-frame handler for the bee, which flies horizontally toward the bat's losing edge and stings on contact. A sting freezes the player's control of the bat until the player loses the last ball or the next level starts.
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Two bees can be live at once, because only the hive checks whether one is already alive. A wave script can place a bee past that check.
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| update_bee | CFB1 | CALL inhabitant_react_state | Reaction-state machine first; carry means skip this frame. | ||||||||
| CFB4 | RET C | ||||||||||
| CFB5 | LD HL,anim_bee | Run the bee animation, and wrap at its last frame. | |||||||||
| CFB8 | CALL advance_anim | ||||||||||
| CFBB | LD A,(IY+$0B) | ||||||||||
| CFBE | CP $02 | ||||||||||
| CFC0 | JR C,bee_home | ||||||||||
| CFC2 | LD (IY+$0B),$00 | ||||||||||
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Home on the bat's losing edge. The heading is rightward when the bat is on the right and leftward when it is on the left. Then advance one step. The bee tracks whichever wall the bat occupies.
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| bee_home | CFC6 | LD A,(bat_side) | Bat on the right: take the rightward heading. | ||||||||
| CFC9 | OR A | ||||||||||
| CFCA | JR NZ,bee_aim_alt | ||||||||||
| CFCC | LD A,$02 | ||||||||||
| CFCE | JR bee_set_heading | ||||||||||
| bee_aim_alt | CFD0 | LD A,$06 | Bat on the left: take the leftward heading instead. | ||||||||
| bee_set_heading | CFD2 | LD (IY+$00),A | Commit the heading and advance one step toward the bat's losing edge. | ||||||||
| CFD5 | CALL move_object | ||||||||||
| CFD8 | CALL inhabitant_offscreen | Despawn off the far edge; carry means gone. | |||||||||
| CFDB | RET C | ||||||||||
| CFDC | LD B,$0A | Award 100 points if a ball hits it. Carry means killed. | |||||||||
| CFDE | CALL ball_kill | ||||||||||
| CFE1 | RET C | ||||||||||
| CFE2 | LD A,C | Name this inhabitant (its slot in C) as the first overlap operand. | |||||||||
| CFE3 | LD (overlap_slot_1),A | ||||||||||
| CFE6 | XOR A | Name the bat as the second overlap operand. | |||||||||
| CFE7 | LD (overlap_slot_2),A | ||||||||||
| bee_check_bat | CFEA | CALL overlap_pair | Reached the bat? | ||||||||
| CFED | OR A | ||||||||||
| CFEE | JR Z,bee_sweep | ||||||||||
| bee_sting | CFF0 | LD (IY+$0B),$00 | Yes: restart the animation and die. | ||||||||
| CFF4 | LD (IY+$0C),$02 | ||||||||||
| CFF8 | LD A,$01 | Raise the sting freeze: the player loses control of the bat. | |||||||||
| CFFA | LD (bat_sting_freeze),A | ||||||||||
| CFFD | RET | ||||||||||
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The sweep's window sits a pixel the other way from the bat test above. A bee that arrives exactly 12 px below or right of the bat is killed against it, and no sting happens.
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| bee_sweep | CFFE | CALL overlap_sweep | No sting: the sweep still takes it in a plain kill. | ||||||||
| D001 | OR A | ||||||||||
| D002 | RET Z | ||||||||||
| D003 | LD (IY+$0B),$00 | Restart the animation and die. | |||||||||
| D007 | LD (IY+$0C),$02 | ||||||||||
| D00B | RET | ||||||||||
| ← CEB3 | Map | D00C → |