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Routines |
| Prev: AD46 | Up: Map | Next: ADBE |
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Sets up the drawing of the new sprite of an object. Finds the sprite from its type and state, and its position on the screen (which frees the slot if it is off screen). If the object is exploding (bit 3 of offset 17), the explosion count in the bottom three bits is increased and the slot is freed when it reaches eight; the count is also used as the dissolve step in A302. The attribute of the sprite is taken from offset 0D, which holds two colours; the choice between them depends on bit 0 of the frame counter at FrameCounter.
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| PrepareDraw | AD48 | LD ($AD46),IX | Update the current object. | |||||
| AD4C | XOR A | Clear A. | ||||||
| AD4D | LD ($A302),A | No dissolve yet. | ||||||
| AD50 | CALL FetchFrameSprite | Call FetchFrameSprite. | ||||||
| AD53 | PUSH DE | Stash DE on the stack. | ||||||
| AD54 | CALL FindObjectScreenPosition | Call FindObjectScreenPosition. | ||||||
| AD57 | POP DE | Bring DE back off the stack. | ||||||
| AD58 | BIT 3,(IX+$17) | Jump to PrepareDraw_Colour if bit 3 of offset 17 of IX is clear. | ||||||
| AD5C | JR Z,PrepareDraw_Colour | |||||||
| AD5E | LD A,(IX+$17) | The second set of flags. | ||||||
| AD61 | AND %00000111 | Keep the bits of A that are set in 07. | ||||||
| AD63 | INC A | Advance A. | ||||||
| AD64 | LD B,A | B=A. | ||||||
| AD65 | CP $08 | Jump to PrepareDraw_Attributes if A is not 08. | ||||||
| AD67 | JR NZ,PrepareDraw_Attributes | |||||||
| AD69 | LD (IX+$00),$FF | Store FF at offset 00 of IX. | ||||||
| AD6D | RES 7,(IX+$10) | Reset bit 7 of offset 10 of IX. | ||||||
| AD71 | JR PrepareDraw_Colour | Jump to PrepareDraw_Colour. | ||||||
| PrepareDraw_Attributes | AD73 | LD A,(IX+$17) | The second set of flags. | |||||
| AD76 | AND %11110000 | Keep the bits of A that are set in F0. | ||||||
| AD78 | OR B | Set the bits of A that are set in B. | ||||||
| AD79 | OR %00001000 | Set the bits of A that are set in 08. | ||||||
| AD7B | LD (IX+$17),A | Write the second set of flags. | ||||||
| AD7E | LD A,B | A=B. | ||||||
| AD7F | OR %10000000 | Set the bits of A that are set in 80. | ||||||
| AD81 | LD ($A302),A | The dissolve step of the explosion. | ||||||
| PrepareDraw_Colour | AD84 | LD A,(IX+$10) | The flags. | |||||
| AD87 | LD ($5C31),A | Update the contact flags. | ||||||
| AD8A | BIT 7,A | Return if bit 7 of A is clear. | ||||||
| AD8C | RET Z | |||||||
| AD8D | LD C,(IX+$0D) | The attribute. | ||||||
| AD90 | LD A,($9A64) | The frame counter. | ||||||
| AD93 | AND %00000001 | Keep the bits of A that are set in 01. | ||||||
| AD95 | JR Z,PrepareDraw_Colour2 | Jump to PrepareDraw_Colour2 if the zero flag is set. | ||||||
| AD97 | LD A,C | A=C. | ||||||
| AD98 | AND %00001000 | Keep the bits of A that are set in 08. | ||||||
| AD9A | ADD A,A | Double A. | ||||||
| AD9B | ADD A,A | Double A. | ||||||
| AD9C | ADD A,A | Double A. | ||||||
| AD9D | LD B,A | B=A. | ||||||
| AD9E | LD A,C | A=C. | ||||||
| AD9F | AND %00000111 | Keep the bits of A that are set in 07. | ||||||
| ADA1 | JR PrepareDraw_Attribute | Jump to PrepareDraw_Attribute. | ||||||
| PrepareDraw_Colour2 | ADA3 | LD A,C | A=C. | |||||
| ADA4 | AND %01110000 | Keep the bits of A that are set in 70. | ||||||
| ADA6 | SRL A | Shift A right. | ||||||
| ADA8 | SRL A | Shift A right. | ||||||
| ADAA | SRL A | Shift A right. | ||||||
| ADAC | SRL A | Shift A right. | ||||||
| ADAE | LD B,A | B=A. | ||||||
| ADAF | LD A,C | A=C. | ||||||
| ADB0 | AND %10000000 | Keep the bits of A that are set in 80. | ||||||
| ADB2 | SRL A | Shift A right. | ||||||
| PrepareDraw_Attribute | ADB4 | OR B | Set the bits of A that are set in B. | |||||
| ADB5 | LD ($AF03),A | The attribute of the sprite. | ||||||
| ADB8 | CALL ClipSecondSprite | Call ClipSecondSprite. | ||||||
| ADBB | JP SelectDrawSprite | Jump to SelectDrawSprite. | ||||||
| Prev: AD46 | Up: Map | Next: ADBE |