Routines
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25306: Locate Radar Cup
Used by the routine at UpdateRadar.
Finds a cup to show on the radar. Each of the 8 cups in CupTable is checked in turn: if the map entry still has the cup sprite ID (32) and the cup is less than 12 cells (of 32 map units) from the player horizontally, then it is placed on the radar by LocateRadarBlip. Only the first such cup is used. If there is no cup then the blip is hidden.
Input
IX Radar blip record
Find the player's horizontal position in cells.
CollisionCup 25306 LD HL,(24069) Fetch the player's X position on the map from PlayerMapPosition.
25309 SLA L Double the value so it matches the scale used by the radar.
25311 RL H
25313 CALL MultiplyHLByFour Call MultiplyHLByFour to multiply the position by 4 which leaves the position in cells in H.
25316 LD C,H Keep the player's X position in cells in C.
25317 LD HL,29215 Point HL at the table of cup map addresses (CupTable).
25320 LD B,8 Set the cup counter to 8 one for each cup.
Fetch the address of the cup from CupTable.
CollisionCup_Loop 25322 LD E,(HL) Fetch the low byte of the map address of this cup.
25323 INC HL Move on to the high byte.
25324 LD D,(HL) Fetch the high byte of the map address of this cup.
25325 INC HL Move on to the next cup in the table.
Check this is still a valid cup (that it hasn't been collected already).
25326 INC DE Point DE at the sprite ID of the map entry.
25327 INC DE
25328 LD A,(DE) If this is not a cup (the sprite ID is not 32) then jump to CollisionCup_Next.
25329 CP 32
25331 JR NZ,CollisionCup_Next
This is still a valid cup, so process it.
25333 DEC DE Point DE back at the start of the map entry.
25334 DEC DE
25335 LD A,(DE) Fetch the X position of the cup.
25336 SUB C Subtract the player's X position to give the horizontal distance.
25337 JR NC,CollisionCup_Test_X Make the distance positive.
25339 NEG
CollisionCup_Test_X 25341 CP 12 If the cup is less than 12 cells away then jump to CollisionCup_Test_Y.
25343 JR C,CollisionCup_Test_Y
CollisionCup_Next 25345 DJNZ CollisionCup_Loop Decrease the cup counter by one and loop back to CollisionCup_Loop until all of the cups have been checked.
25347 JP HideRadarBlip There is no cup in range so jump to HideRadarBlip to hide the blip.
Convert the position of the cup to the same scale used by LocateRadarBlip.
CollisionCup_Test_Y 25350 LD A,(DE) Fetch the X position of the cup.
25351 INC DE Point DE at the Y position of the cup.
25352 LD H,A Keep the X position of the cup in H.
25353 LD A,(DE) Fetch the Y position of the cup.
25354 LD D,A Keep the Y position of the cup in D.
25355 CALL ScaleValue_DivideByEight Call ScaleValue_DivideByEight to set DE to the cup Y position multiplied by 32.
25358 EX DE,HL Swap the DE and HL registers.
25359 CALL ScaleValue Call ScaleValue to set DE to the cup X position multiplied by 64.
25362 EX DE,HL Swap the DE and HL registers.
25363 LD B,H Move the high byte of the doubled X position into B.
25364 LD C,L Move the low byte of the doubled X position into C.
25365 JP LocateRadarBlip Jump to LocateRadarBlip to place the blip (BC is the cup X position and DE is the cup Y position, both doubled).
View the equivalent code in;
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