Routines
Prev: CF14 Up: Map Next: CF68
CF22: Run Wandering Spark
The handler of the object type 59, which is a spark that harms the player. It falls to the floor, and then moves about at random, in a new direction along x and y each time that it is stopped. The sprite of it is turned over every other frame.
Input
IX Object record
Fall, then flip the sprite on every other frame.
RunWanderingSpark CF22 CALL SetSpriteOffset_Minus16_Minus8 Call SetSpriteOffset_Minus16_Minus8 to set the offsets of the sprite.
CF25 CALL SetDeadlyFlags Call SetDeadlyFlags to make the spark harm the player.
CF28 LD (IX+$0B),$00 Set the speed along z to zero.
CF2C CALL ApplyGravityAndMove Call ApplyGravityAndMove to apply gravity to the spark and move it.
CF2F RES 6,(IX+$07) Set the sprite to be the right way round.
CF33 LD A,($A715) Fetch the frame counter.
CF36 AND %00000001 Keep bit 0.
CF38 JR Z,RunWanderingSpark_Test Jump to RunWanderingSpark_Test if it is an even frame.
CF3A SET 6,(IX+$07) Turn the sprite over.
Pick a new direction when the spark is stopped.
RunWanderingSpark_Test CF3E BIT 0,(IX+$0C) Jump to RunWanderingSpark_Turn if the spark was stopped along x.
CF42 JR NZ,RunWanderingSpark_Turn
CF44 BIT 1,(IX+$0C) Jump to RunWanderingSpark_Turn if the spark was stopped along y.
CF48 JR NZ,RunWanderingSpark_Turn
CF4A LD A,(IX+$09) Jump to RunWanderingSpark_Finish if the spark is moving.
CF4D OR (IX+$0A)
CF50 JR NZ,RunWanderingSpark_Finish
RunWanderingSpark_Turn CF52 LD A,($A70D) Fetch the random seed.
CF55 AND %00001000 Keep bit 3.
CF57 SUB $04 Make it FC or 04.
CF59 LD (IX+$09),A Set it as the speed along x.
CF5C LD A,R Fetch a random number from the refresh register.
CF5E AND %00001000 Keep bit 3.
CF60 SUB $04 Make it FC or 04.
CF62 LD (IX+$0A),A Set it as the speed along y.
RunWanderingSpark_Finish CF65 JP SetWipeAndDrawFlags Jump to SetWipeAndDrawFlags to flag the spark as moved.
Prev: CF14 Up: Map Next: CF68