Routines
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45486: Face Direction Of Movement
Used by the routine at HandleBouncingMouse.
Sets the way a robot mouse faces to match the direction in which it is moving, if it is moving along one axis. The way it faces is held in bit 0 of its sprite number and bit 6 of its flags (see TurnMouseOneWay).
Input
IX The address of the object
Face along the axis with the larger speed.
FaceDirectionOfMovement 45486 LD A,(IX+9) Return if the mouse is not moving.
45489 OR (IX+10)
45492 RET Z
45493 LD A,(IX+9) Fetch the speed along the x axis.
45496 CP (IX+10) Jump to FaceDirectionOfMovement_MovingAlongY if the mouse is moving along the y axis.
45499 JR C,FaceDirectionOfMovement_MovingAlongY
45501 BIT 7,A Jump to FaceDirectionOfMovement_West if the mouse is moving west.
45503 JR NZ,FaceDirectionOfMovement_West
45505 SET 0,(IX+0) Set bit 0 of the sprite number.
FaceDirectionOfMovement_Unflip 45509 RES 6,(IX+7) Reset bit 6 of the flags.
45513 RET Return.
The mouse is moving west.
FaceDirectionOfMovement_West 45514 RES 0,(IX+0) Reset bit 0 of the sprite number.
45518 JR FaceDirectionOfMovement_Unflip Jump to FaceDirectionOfMovement_Unflip.
The mouse is moving along the y axis.
FaceDirectionOfMovement_MovingAlongY 45520 BIT 7,(IX+10) Jump to FaceDirectionOfMovement_North if the mouse is moving north.
45524 JR Z,FaceDirectionOfMovement_North
45526 SET 0,(IX+0) Set bit 0 of the sprite number.
FaceDirectionOfMovement_Flip 45530 SET 6,(IX+7) Set bit 6 of the flags.
45534 RET Return.
The mouse is moving north.
FaceDirectionOfMovement_North 45535 RES 0,(IX+0) Reset bit 0 of the sprite number.
45539 JR FaceDirectionOfMovement_Flip Jump to FaceDirectionOfMovement_Flip.
View the equivalent code in;
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