Routines
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70D2: Prepare Actor Sprite
Used by the routines at DisplayEntity and DrawEntity.
Prepares to draw the sprite of an actor at its new position. Points DE to the sprite data and HL to the screen address, stores the pixel shift in NewSpriteShift, the width in bytes in WidthBytes and the number of lines to draw in HeightLines and HeightPixels.
Input
IX Actor entity
Output
DE Sprite data (after the height)
HL Screen address of the bottom left of the sprite
C 00
PrepareActorSprite 70D2 CALL FetchActorSprite Call FetchActorSprite to fetch the sprite.
PrepareActorSprite_Position 70D5 LD L,(IX+$01) L=X position of the actor.
70D8 LD H,(IX+$02) H=Y position of the actor.
This entry point is used by the routines at DisplayCupsCollected and DisplayPlayerLives.
PrepareActorSprite_Shift 70DB LD A,L A=L.
70DC NEG Make A negative.
70DE AND %00000111 Keep only bits 0-2.
70E0 LD ($5E41),A Write the pixel shift to NewSpriteShift.
70E3 LD A,$02 Set the width of the sprite in bytes, 02.
70E5 JR Z,PrepareActorSprite_Width Jump to PrepareActorSprite_Width if the sprite is not shifted.
70E7 INC A Increment A by one (a shifted sprite is one byte wider).
PrepareActorSprite_Width 70E8 LD ($5E24),A Write the width to WidthBytes.
70EB LD ($5E27),HL Write the position to ActorScreenPosition.
70EE CALL GetVisibleHeight Work out how many lines can be drawn using GetVisibleHeight.
70F1 CALL ScreenAddress Convert the position into a screen address using ScreenAddress.
70F4 LD A,(DE) Fetch the height of the sprite.
70F5 CP C Jump to PrepareActorSprite_Rows if the height is no more than the number of lines that can be drawn.
70F6 JR C,PrepareActorSprite_Rows
70F8 LD A,C Use the number of lines that can be drawn, as the sprite is too tall.
PrepareActorSprite_Rows 70F9 LD ($5E26),A Write the number of lines to HeightLines.
70FC LD ($5E23),A Write the number of lines to HeightPixels.
70FF JR NextSprite Jump to NextSprite.
View the equivalent code in;
Prev: 70CE Up: Map Next: 7101