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Routines |
| Prev: 68ED | Up: Map | Next: 696B |
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Used by the routine at UpdateMidges.
Finds the object that the midges are chasing. This is Robbie, unless he is too close to either edge of the play area or the flower is nearer. The distances are measured as the sum of the horizontal and vertical distances at half resolution.
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| FindBugTarget | 690F | LD A,($5E6D) | A=the X position of Robbie. | |||||||||
| 6912 | CP $18 | Jump to FindBugTarget_Flower to use the flower if Robbie is too far to the left. | ||||||||||
| 6914 | JR C,FindBugTarget_Flower | |||||||||||
| 6916 | CP $D8 | Jump to FindBugTarget_Flower to use the flower if Robbie is too far to the right. | ||||||||||
| 6918 | JR NC,FindBugTarget_Flower | |||||||||||
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Distance from the midges to Robbie.
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| 691A | SRL A | B=the X position of Robbie / 02. | ||||||||||
| 691C | LD B,A | |||||||||||
| 691D | LD A,(IX+$01) | A=the X position of the midges / 02. | ||||||||||
| 6920 | SRL A | |||||||||||
| 6922 | SUB B | Subtract the X position of Robbie. | ||||||||||
| 6923 | JP P,FindBugTarget_Robbie_X | Make sure we have a positive byte. | ||||||||||
| 6926 | NEG | |||||||||||
| FindBugTarget_Robbie_X | 6928 | LD B,A | B=the horizontal distance. | |||||||||
| 6929 | LD A,($5E6E) | A=the Y position of Robbie. | ||||||||||
| 692C | SRL A | C=the Y position of Robbie / 02. | ||||||||||
| 692E | LD C,A | |||||||||||
| 692F | LD A,(IX+$02) | A=the Y position of the midges / 02. | ||||||||||
| 6932 | SRL A | |||||||||||
| 6934 | SUB C | Subtract the Y position of Robbie. | ||||||||||
| 6935 | JP P,FindBugTarget_Robbie_Y | Make sure we have a positive byte. | ||||||||||
| 6938 | NEG | |||||||||||
| FindBugTarget_Robbie_Y | 693A | ADD A,B | Add the horizontal distance to get the distance to Robbie. | |||||||||
| 693B | LD D,A | D=the distance to Robbie. | ||||||||||
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Distance from the midges to the flower.
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| 693C | LD A,($5E8D) | A=the X position of the flower. | ||||||||||
| 693F | SRL A | B=the X position of the flower / 02. | ||||||||||
| 6941 | LD B,A | |||||||||||
| 6942 | LD A,(IX+$01) | A=the X position of the midges / 02. | ||||||||||
| 6945 | SRL A | |||||||||||
| 6947 | SUB B | Subtract the X position of the flower. | ||||||||||
| 6948 | JP P,FindBugTarget_Flower_X | Make sure we have a positive byte. | ||||||||||
| 694B | NEG | |||||||||||
| FindBugTarget_Flower_X | 694D | LD B,A | B=the horizontal distance. | |||||||||
| 694E | LD A,($5E8E) | A=the Y position of the flower. | ||||||||||
| 6951 | SRL A | C=the Y position of the flower / 02. | ||||||||||
| 6953 | LD C,A | |||||||||||
| 6954 | LD A,(IX+$02) | A=the Y position of the midges / 02. | ||||||||||
| 6957 | SRL A | |||||||||||
| 6959 | SUB C | Subtract the Y position of the flower. | ||||||||||
| 695A | JP P,FindBugTarget_Flower_Y | Make sure we have a positive byte. | ||||||||||
| 695D | NEG | |||||||||||
| FindBugTarget_Flower_Y | 695F | ADD A,B | Add the horizontal distance to get the distance to the flower. | |||||||||
| 6960 | CP D | Compare the distance to the flower with the distance to Robbie. | ||||||||||
| 6961 | JR C,FindBugTarget_Flower | Jump to FindBugTarget_Flower if the flower is nearer. | ||||||||||
| 6963 | LD HL,$5E6D | HL=State_Robbie_Pos_X (Robbie). | ||||||||||
| 6966 | RET | Return. | ||||||||||
| FindBugTarget_Flower | 6967 | LD HL,$5E8D | HL=State_Flower_Pos_X (the flower). | |||||||||
| 696A | RET | Return. | ||||||||||
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