Routines
Prev: 53012 Up: Map Next: 53096
53026: Run Wandering Spark
The handler of the object type 89, 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 53026 CALL SetSpriteOffset_Minus16_Minus8 Call SetSpriteOffset_Minus16_Minus8 to set the offsets of the sprite.
53029 CALL SetDeadlyFlags Call SetDeadlyFlags to make the spark harm the player.
53032 LD (IX+11),0 Set the speed along z to zero.
53036 CALL ApplyGravityAndMove Call ApplyGravityAndMove to apply gravity to the spark and move it.
53039 RES 6,(IX+7) Set the sprite to be the right way round.
53043 LD A,(42773) Fetch the frame counter.
53046 AND %00000001 Keep bit 0.
53048 JR Z,RunWanderingSpark_Test Jump to RunWanderingSpark_Test if it is an even frame.
53050 SET 6,(IX+7) Turn the sprite over.
Pick a new direction when the spark is stopped.
RunWanderingSpark_Test 53054 BIT 0,(IX+12) Jump to RunWanderingSpark_Turn if the spark was stopped along x.
53058 JR NZ,RunWanderingSpark_Turn
53060 BIT 1,(IX+12) Jump to RunWanderingSpark_Turn if the spark was stopped along y.
53064 JR NZ,RunWanderingSpark_Turn
53066 LD A,(IX+9) Jump to RunWanderingSpark_Finish if the spark is moving.
53069 OR (IX+10)
53072 JR NZ,RunWanderingSpark_Finish
RunWanderingSpark_Turn 53074 LD A,(42765) Fetch the random seed.
53077 AND %00001000 Keep bit 3.
53079 SUB 4 Make it 252 or 4.
53081 LD (IX+9),A Set it as the speed along x.
53084 LD A,R Fetch a random number from the refresh register.
53086 AND %00001000 Keep bit 3.
53088 SUB 4 Make it 252 or 4.
53090 LD (IX+10),A Set it as the speed along y.
RunWanderingSpark_Finish 53093 JP SetWipeAndDrawFlags Jump to SetWipeAndDrawFlags to flag the spark as moved.
Prev: 53012 Up: Map Next: 53096