IF !DEF(FIELD_ASM) DEF FIELD_ASM EQU 1 INCLUDE "globals.asm" DEF DELAY_STATE_DETERMINE_DELAY EQU 0 DEF DELAY_STATE_LINE_CLEAR EQU 1 DEF DELAY_STATE_ARE EQU 2 SECTION "Field Variables", WRAM0 wField:: ds (10*24) wShadowField:: ds (14*26) SECTION "Field High Variables", HRAM hPieceDataBase: ds 2 hPieceDataOffset: ds 1 hCurrentLockDelayRemaining:: ds 1 hDeepestY: ds 1 hWantedTile: ds 1 hWantedG: ds 1 hActualG: ds 1 hTicksUntilG: ds 1 hWantX: ds 1 hYPosAtStartOfFrame: ds 1 hWantRotation: ds 1 hRemainingDelay:: ds 1 hDelayState: ds 1 hClearedLines: ds 4 SECTION "Field Functions", ROM0 FieldInit:: ld hl, wField ld bc, 10*24 ld d, 1 call UnsafeMemSet ld hl, wShadowField ld bc, 14*26 ld d, $FF call UnsafeMemSet ret FieldClear:: ld hl, wField ld bc, 10*24 ld d, TILE_FIELD_EMPTY call UnsafeMemSet ret ToShadowField:: ld hl, wField ld de, wShadowField+2 ld c, 24 .outer ld b, 10 .inner ld a, [hl+] ld [de], a inc de dec b jr nz, .inner inc de inc de inc de inc de dec c jr nz, .outer ret FromShadowField: ld hl, wField ld de, wShadowField+2 ld c, 24 .outer ld b, 10 .inner ld a, [de] ld [hl+], a inc de dec b jr nz, .inner inc de inc de inc de inc de dec c jr nz, .outer ret ; This routine will copy wField onto the screen. BlitField:: ; What to copy ld de, wField + 40 ; Where to put it ld hl, FIELD_TOP_LEFT ; How much to increment hl after each row ld bc, 32-10 ; The first 14 rows can be blitted without checking for vram access. REPT 14 REPT 10 ld a, [de] ld [hl+], a inc de ENDR add hl, bc ENDR : ldh a, [rLY] cp a, 0 jr nz, :- ; The last 6 rows need some care. REPT 6 ; Wait until start of drawing, then insert 35 nops. : ldh a, [rSTAT] and a, 3 cp a, 3 jr nz, :- REPT 35 nop ENDR ; Blit a line. REPT 10 ld a, [de] ld [hl+], a inc de ENDR ; Increment HL so that the next line can be blitted. add hl, bc ENDR ; This has to finish just before the first LCDC interrupt of the frame or stuff will break in weird ways. jp EventLoop SetPieceData: ldh a, [hCurrentPiece] ld hl, sPieceRotationStates ld de, 16 : cp a, 0 jr z, :+ add hl, de dec a jr :- : ld a, l ldh [hPieceDataBase], a ld a, h ldh [hPieceDataBase+1], a ret SetPieceDataOffset: ldh a, [hCurrentPieceRotationState] rlc a rlc a ldh [hPieceDataOffset], a ret ; Converts piece Y in B and a piece X in A to a pointer to the shadow field in HL. XYToSFieldPtr: ld hl, wShadowField ld de, 14 inc a inc b : dec b jr z, :+ add hl, de jr :- : dec a ret z inc hl jr :- ret ; Converts piece Y in B and a piece X in A to a pointer to the field in HL. XYToFieldPtr: ld hl, wField-2 ld de, 10 inc a inc b : dec b jr z, :+ add hl, de jr :- : dec a ret z inc hl jr :- ret GetPieceData: ldh a, [hPieceDataBase] ld l, a ldh a, [hPieceDataBase+1] ld h, a ldh a, [hPieceDataOffset] ld c, a xor a, a ld b, a add hl, bc ret ; Checks if the piece can fit at the current position. ; HL should point to the piece's rotation state data. ; DE should be pointing to the right place in the SHADOW field. CanPieceFit: xor a, a ld b, a ; Row 1 bit 3, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 2, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 1, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 0, [hl] jr z, .r1end ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz .r1end REPT 11 inc de ENDR ; Row 2 inc hl bit 3, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 2, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 1, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 0, [hl] jr z, .r2end ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz .r2end REPT 11 inc de ENDR ; Row 3 inc hl bit 3, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 2, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 1, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 0, [hl] jr z, .r3end ld a, [de] cp a, TILE_FIELD_EMPTY ret nz .r3end REPT 11 inc de ENDR ; Row 4 inc hl bit 3, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 2, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 1, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz : inc de inc b bit 0, [hl] jr z, :+ ld a, [de] cp a, TILE_FIELD_EMPTY ld a, b ret nz ; If we got here, the piece can fit. : ld a, $FF ret TrySpawnPiece:: ; Always reset these for a new piece. ldh a, [hCurrentLockDelay] ldh [hCurrentLockDelayRemaining], a ldh a, [hCurrentFramesPerGravityTick] ldh [hTicksUntilG], a ld a, $FF ldh [hRemainingDelay], a ld a, DELAY_STATE_DETERMINE_DELAY ldh [hDelayState], a ; Copy the field to the shadow field. call ToShadowField ; Point the piece data to the correct piece. call SetPieceData call SetPieceDataOffset ; Get the piece's spawn position. ldh a, [hCurrentPieceY] ld b, a ldh a, [hCurrentPieceX] call XYToSFieldPtr ; Check if the piece can spawn. ld d, h ld e, l call GetPieceData call CanPieceFit ; A will be $FF if the piece can fit. cp a, $FF ret z ; Otherwise check the rotation, and if it's not zero, try to reset it. ldh a, [hCurrentPieceRotationState] cp a, 0 ret nz ; Reset the rotation. xor a, a ldh [hCurrentPieceRotationState], a call SetPieceDataOffset ldh a, [hCurrentPieceY] ld b, a ldh a, [hCurrentPieceX] call XYToSFieldPtr ld d, h ld e, l call GetPieceData jp CanPieceFit ; Draws the piece onto the field. ; B is the tile. ; DE should point to the piece's rotation state data. ; HL should be pointing to the right place in the NORMAL field. DrawPiece: ld a, [de] inc de bit 3, a jr z, :+ ld [hl], b : inc hl bit 2, a jr z, :+ ld [hl], b : inc hl bit 1, a jr z, :+ ld [hl], b : inc hl bit 0, a jr z, .r1end2 ld [hl], b .r1end2 REPT 7 inc hl ENDR ld a, [de] inc de bit 3, a jr z, :+ ld [hl], b : inc hl bit 2, a jr z, :+ ld [hl], b : inc hl bit 1, a jr z, :+ ld [hl], b : inc hl bit 0, a jr z, .r2end2 ld [hl], b .r2end2 REPT 7 inc hl ENDR ld a, [de] inc de bit 3, a jr z, :+ ld [hl], b : inc hl bit 2, a jr z, :+ ld [hl], b : inc hl bit 1, a jr z, :+ ld [hl], b : inc hl bit 0, a jr z, .r3end2 ld [hl], b .r3end2 REPT 7 inc hl ENDR ld a, [de] inc de bit 3, a jr z, :+ ld [hl], b : inc hl bit 2, a jr z, :+ ld [hl], b : inc hl bit 1, a jr z, :+ ld [hl], b : inc hl bit 0, a ret z ld [hl], b ret FindMaxG: ; Find the deepest the piece can go. ; We cache this pointer, cause it otherwise takes too much time. ldh a, [hCurrentPieceY] ld b, a ldh a, [hCurrentPieceX] call XYToSFieldPtr push hl ld a, 2 ldh [hActualG], a .try ld de, 28 pop hl add hl, de push hl ld d, h ld e, l call GetPieceData call CanPieceFit cp a, $FF jr nz, .foundmaybe ldh a, [hActualG] inc a inc a ldh [hActualG], a jr .try .foundmaybe ldh a, [hActualG] dec a ldh [hActualG], a ld de, -14 pop hl add hl, de push hl ld d, h ld e, l call GetPieceData call CanPieceFit cp a, $FF jr nz, .found pop hl ret .found pop hl ldh a, [hActualG] dec a ldh [hActualG], a ret FieldProcess:: ; Wipe out the piece. ldh a, [hCurrentPieceY] ldh [hYPosAtStartOfFrame], a call FromShadowField ; Check if we're about to hold. ld a, [hSelectState] cp a, 1 jr nz, :+ ld a, [hHoldSpent] cp a, $FF ret nz ; How deep can we go? : call FindMaxG ; If we press up, we want to do a sonic drop. ldh a, [hUpState] cp a, 1 jr nz, :+ ld a, 20 ldh [hWantedG], a ldh a, [hTicksUntilG] dec a ldh [hTicksUntilG], a jr nz, .grav ldh a, [hCurrentFramesPerGravityTick] ldh [hTicksUntilG], a jr .grav ; If we press down, we want to do a soft drop. : ldh a, [hDownState] cp a, 0 jr z, :+ ld a, 1 ldh [hTicksUntilG], a ; Gravity? : ldh a, [hTicksUntilG] dec a ldh [hTicksUntilG], a jr nz, .nograv ldh a, [hCurrentFramesPerGravityTick] ldh [hTicksUntilG], a ldh a, [hCurrentGravityPerTick] ldh [hWantedG], a .grav ldh a, [hWantedG] ld b, a ldh a, [hActualG] cp a, b jr c, .smallg .bigg ldh a, [hWantedG] ld b, a ldh a, [hCurrentPieceY] add a, b ldh [hCurrentPieceY], a jr .nograv .smallg ldh a, [hActualG] ld b, a ldh a, [hCurrentPieceY] add a, b ldh [hCurrentPieceY], a .nograv ldh a, [hCurrentPieceX] ldh [hWantX], a ldh a, [hCurrentPieceRotationState] ldh [hWantRotation], a ; Want left? .wantleft ldh a, [hLeftState] cp a, 1 jr z, :+ ld b, a ldh a, [hCurrentDAS] ld c, a ld a, b cp a, c jr c, .wantright : ldh a, [hWantX] dec a ldh [hWantX], a ; Want right? .wantright ldh a, [hRightState] cp a, 1 jr z, :+ ld b, a ldh a, [hCurrentDAS] ld c, a ld a, b cp a, c jr c, .wantrotccw : ldh a, [hWantX] inc a ldh [hWantX], a ; Want rotate CCW? .wantrotccw ldh a, [hAState] cp a, 1 jr nz, .wantrotcw ldh a, [hWantRotation] inc a and a, $03 ldh [hWantRotation], a ; Want rotate CW? .wantrotcw ldh a, [hBState] cp a, 1 jr nz, .moverotrequested ldh a, [hWantRotation] dec a and a, $03 ldh [hWantRotation], a ; Do we need to try to move/rotate the piece? .moverotrequested ldh a, [hWantRotation] ld b, a ldh a, [hCurrentPieceRotationState] cp a, b jr nz, .trymoverot ; Move and rotate. ldh a, [hWantX] ld b, a ldh a, [hCurrentPieceX] cp a, b jp z, .postmove ; Neither move nor rotate. ; Move only. ldh a, [hCurrentPieceY] ld b, a ldh a, [hWantX] call XYToSFieldPtr ld d, h ld e, l call GetPieceData call CanPieceFit cp a, $FF jp nz, .postmove ldh a, [hWantX] ldh [hCurrentPieceX], a jp .postmove .trymoverot ldh a, [hCurrentPieceY] ld b, a ldh a, [hWantX] call XYToSFieldPtr ld d, h ld e, l ldh a, [hPieceDataBase] ld l, a ldh a, [hPieceDataBase+1] ld h, a ldh a, [hWantRotation] rlc a rlc a push bc ld c, a xor a, a ld b, a add hl, bc pop bc call CanPieceFit cp a, $FF jr nz, .maybekick ldh a, [hWantX] ldh [hCurrentPieceX], a ldh a, [hWantRotation] ldh [hCurrentPieceRotationState], a call SetPieceDataOffset jp .postmove ; Try kicks if the piece isn't I or O. And in the case of J L and T, only if the blocked side is the left or right. .maybekick ld c, a ldh a, [hCurrentPiece] cp a, PIECE_I jr z, .postmove cp a, PIECE_O jr z, .postmove cp a, PIECE_S jr z, .trykickright cp a, PIECE_Z jr z, .trykickright ld a, c cp a, 1 jr z, .postmove cp a, 5 jr z, .postmove cp a, 9 jr z, .postmove .trykickright ldh a, [hCurrentPieceY] ld b, a ldh a, [hWantX] inc a call XYToSFieldPtr ld d, h ld e, l ldh a, [hPieceDataBase] ld l, a ldh a, [hPieceDataBase+1] ld h, a ldh a, [hWantRotation] rlc a rlc a push bc ld c, a xor a, a ld b, a add hl, bc pop bc call CanPieceFit cp a, $FF jr nz, .trykickleft ldh a, [hWantX] inc a ldh [hCurrentPieceX], a ldh a, [hWantRotation] ldh [hCurrentPieceRotationState], a call SetPieceDataOffset jr .postmove .trykickleft ldh a, [hCurrentPieceY] ld b, a ldh a, [hWantX] dec a call XYToSFieldPtr ld d, h ld e, l ldh a, [hPieceDataBase] ld l, a ldh a, [hPieceDataBase+1] ld h, a ldh a, [hWantRotation] rlc a rlc a push bc ld c, a xor a, a ld b, a add hl, bc pop bc call CanPieceFit cp a, $FF jr nz, .postmove ldh a, [hWantX] dec a ldh [hCurrentPieceX], a ldh a, [hWantRotation] ldh [hCurrentPieceRotationState], a call SetPieceDataOffset .postmove ; Are we grounded? ldh a, [hCurrentPieceY] inc a ld b, a ldh a, [hCurrentPieceX] call XYToSFieldPtr ld d, h ld e, l call GetPieceData call CanPieceFit cp a, $FF jr z, .notgrounded ; We're grounded. ; If the y position changed, play a sound. ldh a, [hCurrentPieceY] ld b, a ldh a, [hYPosAtStartOfFrame] cp a, b jr z, :+ ldh a, [hDownState] cp a, 0 jr nz, :+ ld a, SFX_DROP call SFXEnqueue ; If the down button is held, lock. : ldh a, [hDownState] cp a, 0 jr z, :+ ld a, 1 ldh [hCurrentLockDelayRemaining], a : ldh a, [hCurrentLockDelayRemaining] dec a ldh [hCurrentLockDelayRemaining], a ; If we're out of lock delay, play a sound. cp a, 0 jr nz, .draw ld a, SFX_LOCK call SFXEnqueue jr .draw .notgrounded ; Otherwise reset the lock delay. ldh a, [hCurrentLockDelay] ldh [hCurrentLockDelayRemaining], a ; Draw the piece. .draw ; If the gravity is <= 1G, draw a ghost piece. ldh a, [hWantedG] cp a, 1 jr nz, :+ ldh a, [hEvenFrame] cp a, 1 jr nz, :+ ldh a, [hYPosAtStartOfFrame] ld b, a ldh a, [hActualG] add a, b ld b, a ldh a, [hCurrentPieceX] call XYToFieldPtr ld d, h ld e, l call GetPieceData ld a, 0 ld b, a push hl push de pop hl pop de call DrawPiece ; If the lock delay is at the highest value, draw the piece normally. : ldh a, [hCurrentPiece] ld b, TILE_PIECE_0 add a, b ldh [hWantedTile], a ldh a, [hCurrentLockDelay] ld b, a ldh a, [hCurrentLockDelayRemaining] cp a, b jr z, .drawpiece ; If the lock delay is 0, draw the piece in the final color. ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+7 add a, b ldh [hWantedTile], a ldh a, [hCurrentLockDelayRemaining] cp a, 0 jr z, .drawpiece ; Otherwise, look it up. call GetTileShade ; TODO: What tile do we use to draw the piece? .drawpiece ldh a, [hCurrentPieceY] ld b, a ldh a, [hCurrentPieceX] call XYToFieldPtr ld d, h ld e, l call GetPieceData ldh a, [hWantedTile] ld b, a push hl push de pop hl pop de call DrawPiece ret GetTileShade: ; Possible values for tile delay: ; 30, 25, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 1 ; We don't need to handle the 1 case. ld a, 0 ld b, a : ldh a, [hCurrentLockDelay] cp a, 30 jr z, .max30 : cp a, 25 jr z, .max25 : cp a, 20 jr z, .max20 : cp a, 18 jp z, .max18 : cp a, 16 jp z, .max16 : cp a, 14 jp z, .max14 : cp a, 12 jp z, .max12 : cp a, 10 jp z, .max10 : cp a, 8 jp z, .max8 : cp a, 6 jp z, .max6 : cp a, 4 jp z, .max4 : cp a, 2 jp z, .max2 ret .max30 ld a, [hCurrentLockDelayRemaining] cp a, 4 ret c cp a, 8 jp c, .s6 cp a, 12 jp c, .s5 cp a, 16 jp c, .s4 cp a, 20 jp c, .s3 cp a, 24 jp c, .s2 cp a, 28 jp c, .s1 jp .s0 .max25 ld a, [hCurrentLockDelayRemaining] cp a, 3 ret c cp a, 6 jp c, .s6 cp a, 9 jp c, .s5 cp a, 12 jp c, .s4 cp a, 15 jp c, .s3 cp a, 18 jp c, .s2 cp a, 21 jp c, .s1 jp .s0 .max20 ld a, [hCurrentLockDelayRemaining] cp a, 2 ret c cp a, 5 jp c, .s6 cp a, 7 jp c, .s5 cp a, 10 jp c, .s4 cp a, 12 jp c, .s3 cp a, 15 jp c, .s2 cp a, 17 jp c, .s1 jp .s0 .max18 ld a, [hCurrentLockDelayRemaining] cp a, 2 ret c cp a, 4 jp c, .s6 cp a, 6 jp c, .s5 cp a, 9 jp c, .s4 cp a, 11 jp c, .s3 cp a, 13 jp c, .s2 cp a, 15 jp c, .s1 jp .s0 .max16 ld a, [hCurrentLockDelayRemaining] cp a, 2 ret c cp a, 4 jp c, .s6 cp a, 6 jp c, .s5 cp a, 8 jp c, .s4 cp a, 10 jp c, .s3 cp a, 12 jp c, .s2 cp a, 14 jp c, .s1 jp .s0 .max14 ld a, [hCurrentLockDelayRemaining] cp a, 2 ret c cp a, 4 jp c, .s6 cp a, 6 jp c, .s5 cp a, 7 jp c, .s4 cp a, 9 jp c, .s3 cp a, 11 jp c, .s2 cp a, 13 jp c, .s1 jp .s0 .max12 ld a, [hCurrentLockDelayRemaining] cp a, 1 ret c cp a, 3 jp c, .s6 cp a, 4 jp c, .s5 cp a, 6 jp c, .s4 cp a, 7 jp c, .s3 cp a, 9 jp c, .s2 cp a, 10 jp c, .s1 jp .s0 .max10 ld a, [hCurrentLockDelayRemaining] cp a, 1 ret c cp a, 2 jp c, .s6 cp a, 3 jp c, .s5 cp a, 5 jr c, .s4 cp a, 6 jr c, .s3 cp a, 7 jr c, .s2 cp a, 8 jr c, .s1 jr .s0 .max8 ld a, [hCurrentLockDelayRemaining] cp a, 1 ret c cp a, 2 jr c, .s6 cp a, 3 jr c, .s5 cp a, 4 jr c, .s4 cp a, 5 jr c, .s3 cp a, 6 jr c, .s2 cp a, 7 jr c, .s1 jr .s0 .max6 ld a, [hCurrentLockDelayRemaining] cp a, 1 ret c cp a, 2 jr c, .s5 cp a, 3 jr c, .s3 cp a, 4 jr c, .s2 cp a, 5 jr c, .s1 jr .s0 .max4 ld a, [hCurrentLockDelayRemaining] cp a, 1 ret c cp a, 2 jr c, .s4 jr .s0 .max2 ld a, [hCurrentLockDelayRemaining] jr .s4 .s0 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0 add a, b ldh [hWantedTile], a ret .s1 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+(2*7) add a, b ldh [hWantedTile], a ret .s2 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+(3*7) add a, b ldh [hWantedTile], a ret .s3 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+(4*7) add a, b ldh [hWantedTile], a ret .s4 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+(5*7) add a, b ldh [hWantedTile], a ret .s5 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+(6*7) add a, b ldh [hWantedTile], a ret .s6 ldh a, [hCurrentPiece] ld b, TILE_PIECE_0+(7*7) add a, b ldh [hWantedTile], a ret FieldDelay:: ldh a, [hDelayState] cp DELAY_STATE_DETERMINE_DELAY jr z, .determine cp DELAY_STATE_LINE_CLEAR jr z, .lineclear cp DELAY_STATE_ARE jr z, .are .determine call FindClearedLines ldh a, [hClearedLines] ld b, a ldh a, [hClearedLines+1] ld c, a ldh a, [hClearedLines+2] ld d, a ldh a, [hClearedLines+3] and a, b and a, c and a, d cp a, $FF jr z, .skip ld a, DELAY_STATE_LINE_CLEAR ldh [hDelayState], a ldh a, [hCurrentLineClearDelay] ldh [hRemainingDelay], a call MarkClear jr .lineclear .skip ld a, DELAY_STATE_ARE ldh [hDelayState], a ldh a, [hCurrentARE] ldh [hRemainingDelay], a jr .are .lineclear ldh a, [hRemainingDelay] dec a ldh [hRemainingDelay], a cp a, 0 ret nz call ClearLines call SFXKill ld a, SFX_DROP call SFXEnqueue ld a, DELAY_STATE_ARE ldh [hDelayState], a ldh a, [hCurrentARE] ldh [hRemainingDelay], a .are ldh a, [hRemainingDelay] dec a ldh [hRemainingDelay], a cp a, 0 ret nz ; If we're out of delay, spawn a new piece. call SFXKill ret AppendClearedLine: ldh a, [hClearedLines+2] ldh [hClearedLines+3], a ldh a, [hClearedLines+1] ldh [hClearedLines+2], a ldh a, [hClearedLines] ldh [hClearedLines+1], a ld a, b ldh [hClearedLines], a ret FindClearedLines: ld a, $FF ld c, 0 ldh [hClearedLines], a ldh [hClearedLines+1], a ldh [hClearedLines+2], a ldh [hClearedLines+3], a DEF row = 23 REPT 24 ld hl, wShadowField+2+(row*14) ld b, 11 : ld a, [hl+] dec b cp a, $FF jr z, :+ cp a, TILE_FIELD_EMPTY jr nz, :- : xor a, a cp a, b jr nz, .next\@ ld b, 23-row call AppendClearedLine inc c ld a, 4 cp a, c ret z DEF row -= 1 .next\@ ENDR ret MarkClear: ld a, [hClearedLines] cp a, $FF ret z ld hl, wField+(24*10) : ld bc, -10 add hl, bc dec a cp a, $FF jr nz, :- ld bc, 10 ld d, TILE_CLEARING call UnsafeMemSet ld a, [hClearedLines+1] cp a, $FF ret z ld hl, wField+(24*10) : ld bc, -10 add hl, bc dec a cp a, $FF jr nz, :- ld bc, 10 ld d, TILE_CLEARING call UnsafeMemSet ld a, [hClearedLines+2] cp a, $FF ret z ld hl, wField+(24*10) : ld bc, -10 add hl, bc dec a cp a, $FF jr nz, :- ld bc, 10 ld d, TILE_CLEARING call UnsafeMemSet ld a, [hClearedLines+3] cp a, $FF ret z ld hl, wField+(24*10) : ld bc, -10 add hl, bc dec a cp a, $FF jr nz, :- ld bc, 10 ld d, TILE_CLEARING call UnsafeMemSet ret ClearLines: ld de, 0 DEF row = 23 REPT 24 ; Check if the row begins with a clearing tile. ld hl, wField+(row*10) ld a, [hl] cp a, TILE_CLEARING ; If it does, increment the clearing counter, but skip this line. jr nz, .clear\@ inc de inc de inc de inc de inc de inc de inc de inc de inc de inc de jr .r\@ .clear\@ ; If there's 0 lines that need to be moved down, skip this line. xor a, a cp a, e jr z, .r\@ ; Otherwise... ld bc, wField+(row*10) add hl, de : ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc ld a, [bc] ld [hl+], a inc bc .r\@ DEF row -= 1 ENDR ret ENDC