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Routines |
| Prev: AEE0 | Up: Map | Next: AF19 |
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Used by the routine at MoveLights.
Starts a new light, in a slot that is not in use. The light is given a random colour and direction, and a random delay. It starts at the top left of the frame of the screen, which is made of attributes of the value 48. The lights then move along the frame, one cell a frame.
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| StartLight | AEED | PUSH HL | Copy the address of the slot into IX... | |||||
| AEEE | POP IX | Pop it into IX. | ||||||
| AEF0 | LD A,($9617) | Fetch the random number... | ||||||
| AEF3 | LD E,A | ...and keep it in E. | ||||||
| AEF4 | AND $03 | Keep the low two bits... | ||||||
| AEF6 | LD L,A | |||||||
| AEF7 | LD H,$00 | ...and clear H. | ||||||
| AEF9 | LD BC,$AF19 | Point BC at LightColours. | ||||||
| AEFC | ADD HL,BC | Add the offset. | ||||||
| AEFD | LD D,(HL) | Fetch the colour... | ||||||
| AEFE | LD A,E | ...and fetch the random number again. | ||||||
| AEFF | AND $18 | Keep the bits that choose the direction, and add the colour. | ||||||
| AF01 | OR D | |||||||
| AF02 | LD (IX+$00),A | Store the type of the light. | ||||||
| AF05 | LD A,($9617) | Fetch the random number again... | ||||||
| AF08 | AND $3F | ...keep a number between 00 and 3F, and add 20 to it... | ||||||
| AF0A | OR $20 | |||||||
| AF0C | LD (IX+$01),A | ...to find the time before the light can finish. | ||||||
| AF0F | LD (IX+$02),$21 | Store the low byte of the address of the attribute, 21... | ||||||
| AF13 | LD (IX+$03),$58 | ...and the high byte, 58. | ||||||
| AF17 | JR MoveLights_Update | Jump to move the lights. | ||||||
| Prev: AEE0 | Up: Map | Next: AF19 |