Implement TGM3 and world modes fully.

README.md

@@ -12,11 +12,14 @@ The Randomizer uses a TGM2-style 4-history randomizer preloaded with SSZZ, and w
 The game itself runs at a constant 60fps as well as at the traditional 20 row visible grid.
 
 There are five available game modes:
-- TGM1: 4 history, 4 rerolls, no sonic drop, never start with O, S or Z.
+- TGM1: 4 history w/ 4 rerolls, never start with O, S or Z.
-- TGM2: 4 history, 6 rerolls, sonic drop, never start with O, S or Z.
+- TGM2: 4 history w/ 6 rerolls, never start with O, S or Z. Sonic drop.
-- TGM3: 6 history, 6 rerolls, sonic drop, never start with O, S or Z. (Note, not the actual 35-bag as used in TGM3, and floor kicks are not implemented (yet) either.)
+- TGM3: 4 history w/ 6 rerolls and drought protection, never start with O, S or Z. Sonic drop. Extra floor and wall kicks for I and T pieces.
-- HELL: No history, no rerolls, no sonic drop, never start with O, S or Z.
+- HELL: Pure random piece generation.
-- EASY: 6 history, 256 rerolls, sonic drop, never start with O, S or Z.
+- EASY: 4 history w/ 256 rerolls, never start with O, S or Z. Sonic drop.
+- TGW2: TGM2 but with hard drop.
+- TGW3: TGM3 but with hard drop.
+- EAWY: EASY but with hard drop.
 
 
 ## Playing

src/constants.asm

@@ -467,5 +467,17 @@ sPieceRotationStates:: ; How each piece is rotated.
     db %0100
     db %0000
 
+sTGM3Bag::
+    db 0, 0, 0, 0, 0
+    db 1, 1, 1, 1, 1
+    db 2, 2, 2, 2, 2
+    db 3, 3, 3, 3, 3
+    db 4, 4, 4, 4, 4
+    db 5, 5, 5, 5, 5
+    db 6, 6, 6, 6, 6
+
+sTGM3Droughts::
+    db 0, 0, 0, 0, 0, 0, 0
+
 
 ENDC

src/field.asm

@@ -50,6 +50,7 @@ hDelayState: ds 1
 hClearedLines: ds 4
 hLineClearCt: ds 1
 hComboCt: ds 1
+hLockDelayForce: ds 1
 
 
 SECTION "Field Functions", ROM0
@@ -496,6 +497,8 @@ ForceSpawnPiece::
 
 TrySpawnPiece::
     ; Always reset these for a new piece.
+    xor a, a
+    ldh [hLockDelayForce], a
     ldh a, [hCurrentLockDelay]
     ldh [hCurrentLockDelayRemaining], a
     ldh a, [hCurrentFramesPerGravityTick]
@@ -679,13 +682,15 @@ FindMaxG:
 
 
 FieldProcess::
+    ; **************************************************************
+    ; SETUP
     ; Wipe out the piece.
     ldh a, [hCurrentPieceY]
     ldh [hYPosAtStartOfFrame], a
     call FromShadowField
 
 
-    ; Check if we're about to hold.
+    ; Check if we're about to hold. Return if so.
     ldh a, [hSelectState]
     cp a, 1
     jr nz, :+
@@ -693,19 +698,32 @@ FieldProcess::
     cp a, $FF
     ret nz
 
-
     ; How deep can we go?
 :   call FindMaxG
 
-    ; If we press up, we want to do a sonic drop, but not in TGM1 or HELL mode.
+
-    ldh a, [hSimulationMode]
+    ; **************************************************************
-    cp a, MODE_TGM1
+    ; HANDLE UP
-    jr z, :+
+    ; Is a hard/sonic drop requested?
-    cp a, MODE_HELL
-    jr z, :+
     ldh a, [hUpState]
     cp a, 1
-    jr nz, :+
+    jr nz, .postdrop
+
+    ; What kind, if any?
+    ldh a, [hSimulationMode]
+    cp a, MODE_TGM1
+    jr z, .postdrop
+    cp a, MODE_HELL
+    jr z, .postdrop
+    cp a, MODE_TGW2
+    jr z, .harddrop
+    cp a, MODE_TGW3
+    jr z, .harddrop
+    cp a, MODE_EAWY
+    jr z, .harddrop
+
+    ; Sonic drop.
+.sonicdrop
     ld a, 20
     ldh [hWantedG], a
     ldh a, [hTicksUntilG]
@@ -716,15 +734,32 @@ FieldProcess::
     ldh [hTicksUntilG], a
     jr .grav
 
+    ; Hard drop.
+.harddrop
+    ld a, 20
+    ld b, a
+    ldh a, [hActualG]
+    cp a, b
+    jr nc, :+
+    ld b, a
+:   ldh a, [hCurrentPieceY]
+    add a, b
+    ldh [hCurrentPieceY], a
+    xor a, a
+    ldh [hCurrentLockDelayRemaining], a
+    call SFXKill
+    ld a, SFX_LOCK
+    call SFXEnqueue
+    jp .draw
 
     ; If we press down, we want to do a soft drop.
-:   ldh a, [hDownState]
+.postdrop
+    ldh a, [hDownState]
     cp a, 0
     jr z, :+
     ld a, 1
     ldh [hTicksUntilG], a
 
-
     ; Gravity?
 :   ldh a, [hTicksUntilG]
     dec a
@@ -735,7 +770,7 @@ FieldProcess::
     ldh a, [hCurrentGravityPerTick]
     ldh [hWantedG], a
 
-
+    ; Can we drop the full requested distance?
 .grav
     ldh a, [hWantedG]
     ld b, a
@@ -743,7 +778,7 @@ FieldProcess::
     cp a, b
     jr c, .smallg
 
-
+    ; Yes. Do it.
 .bigg
     ldh a, [hWantedG]
     ld b, a
@@ -752,7 +787,7 @@ FieldProcess::
     ldh [hCurrentPieceY], a
     jr .nograv
 
-
+    ; No. Smaller distance.
 .smallg
     ldh a, [hActualG]
     ld b, a
@@ -760,14 +795,16 @@ FieldProcess::
     add a, b
     ldh [hCurrentPieceY], a
 
-
+    ; No gravity, or post gravity.
 .nograv
     ldh a, [hCurrentPieceX]
     ldh [hWantX], a
     ldh a, [hCurrentPieceRotationState]
     ldh [hWantRotation], a
 
-    ; We check rotation first.
+
+    ; **************************************************************
+    ; HANDLE ROTATION
     ; Want rotate CCW?
 .wantrotccw
     ldh a, [hSwapAB]
@@ -787,7 +824,6 @@ FieldProcess::
     ldh [hWantRotation], a
     jr .tryrot
 
-
     ; Want rotate CW?
 .wantrotcw
     ldh a, [hSwapAB]
@@ -806,7 +842,6 @@ FieldProcess::
     and a, $03
     ldh [hWantRotation], a
 
-
     ; Try the rotation.
 .tryrot
     ldh a, [hCurrentPieceY]
@@ -836,26 +871,40 @@ FieldProcess::
     call SetPieceDataOffset
     jp .norot
 
-
     ; 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
+    ; O pieces never kick, obviously.
-    jr z, .norot
     cp a, PIECE_O
-    jr z, .norot
+    jp z, .norot
+
+    ; S/Z always kick.
     cp a, PIECE_S
     jr z, .trykickright
     cp a, PIECE_Z
     jr z, .trykickright
-    ld a, c
+
+    ; I piece only kicks in TGM3/TGW3/EASY/EAWY
+    cp a, PIECE_I
+    jr nz, :+
+    ldh a, [hSimulationMode]
+    cp a, MODE_TGM1
+    jp z, .norot
+    cp a, MODE_TGM2
+    jp z, .norot
+    cp a, MODE_HELL
+    jp z, .norot
+    jr .trykickright
+
+    ; T/L/J only kick if not through the middle axis.
+:   ld a, c
     cp a, 1
-    jr z, .norot
+    jr z, .maybetgm3rot
     cp a, 5
-    jr z, .norot
+    jr z, .maybetgm3rot
     cp a, 9
-    jr z, .norot
+    jr z, .maybetgm3rot
 
     ; A step to the right.
 .trykickright
@@ -888,8 +937,7 @@ FieldProcess::
     ldh a, [hWantRotation]
     ldh [hCurrentPieceRotationState], a
     call SetPieceDataOffset
-    jr .norot
+    jp .norot
-
 
     ; And a step to the left.
 .trykickleft
@@ -915,15 +963,185 @@ FieldProcess::
     pop bc
     call CanPieceFitFast
     cp a, $FF
-    jr nz, .norot
+    jr nz, .maybetgm3rot
     ldh a, [hCurrentPieceX]
     dec a
     ldh [hCurrentPieceX], a
     ldh a, [hWantRotation]
     ldh [hCurrentPieceRotationState], a
     call SetPieceDataOffset
+    jp .norot
+
+    ; In TGM3, TGW3, EASY, and EAWY modes, there are a few other kicks possible.
+.maybetgm3rot
+    ldh a, [hSimulationMode]
+    cp a, MODE_TGM1
+    jp z, .norot
+    cp a, MODE_TGM2
+    jp z, .norot
+    cp a, MODE_HELL
+    jp z, .norot
+
+    ; In the case of a T piece, try the space above.
+.checkt
+    ldh a, [hCurrentPiece]
+    cp a, PIECE_T
+    jr nz, .checki
+
+    ldh a, [hCurrentPieceY]
+    dec a
+    ld b, a
+    ldh a, [hCurrentPieceX]
+    call XYToSFieldPtr
+    ld d, h
+    ld e, l
+    ldh a, [hPieceDataBaseFast]
+    ld l, a
+    ldh a, [hPieceDataBaseFast+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 CanPieceFitFast
+    cp a, $FF
+    jp nz, .norot
+    ldh a, [hCurrentPieceY]
+    dec a
+    ldh [hCurrentPieceY], a
+    ldh a, [hWantRotation]
+    ldh [hCurrentPieceRotationState], a
+    call SetPieceDataOffset
+    ld a, $FF
+    ldh [hLockDelayForce], a
+    jp .norot
+
+    ; In the case of an I piece...
+.checki
+    ldh a, [hCurrentPiece]
+    cp a, PIECE_I
+    jp nz, .norot
+
+    ; Are we grounded?
+    ; If not, we can only kick right twice.
+    ldh a, [hActualG]
+    cp a, 0
+    jr nz, .tryiright2
+
+    ; Try up once.
+.tryiup1
+    ldh a, [hCurrentPieceY]
+    dec a
+    ld b, a
+    ldh a, [hCurrentPieceX]
+    call XYToSFieldPtr
+    ld d, h
+    ld e, l
+    ldh a, [hPieceDataBaseFast]
+    ld l, a
+    ldh a, [hPieceDataBaseFast+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 CanPieceFitFast
+    cp a, $FF
+    jr nz, .tryiup2
+    ldh a, [hCurrentPieceY]
+    dec a
+    ldh [hCurrentPieceY], a
+    ldh a, [hWantRotation]
+    ldh [hCurrentPieceRotationState], a
+    call SetPieceDataOffset
+    ld a, $FF
+    ldh [hLockDelayForce], a
+    jr .norot
+
+    ; Try up twice.
+.tryiup2
+    ldh a, [hCurrentPieceY]
+    dec a
+    dec a
+    ld b, a
+    ldh a, [hCurrentPieceX]
+    call XYToSFieldPtr
+    ld d, h
+    ld e, l
+    ldh a, [hPieceDataBaseFast]
+    ld l, a
+    ldh a, [hPieceDataBaseFast+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 CanPieceFitFast
+    cp a, $FF
+    jr nz, .tryiright2
+    ldh a, [hCurrentPieceY]
+    dec a
+    dec a
+    ldh [hCurrentPieceY], a
+    ldh a, [hWantRotation]
+    ldh [hCurrentPieceRotationState], a
+    call SetPieceDataOffset
+    ld a, $FF
+    ldh [hLockDelayForce], a
+    jr .norot
+
+    ; Try right twice.
+.tryiright2
+    ldh a, [hCurrentPieceY]
+    ld b, a
+    ldh a, [hCurrentPieceX]
+    inc a
+    inc a
+    call XYToSFieldPtr
+    ld d, h
+    ld e, l
+    ldh a, [hPieceDataBaseFast]
+    ld l, a
+    ldh a, [hPieceDataBaseFast+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 CanPieceFitFast
+    cp a, $FF
+    jr nz, .norot
+    ldh a, [hCurrentPieceX]
+    inc a
+    inc a
+    ldh [hCurrentPieceX], a
+    ldh a, [hWantRotation]
+    ldh [hCurrentPieceRotationState], a
+    call SetPieceDataOffset
 
 
+    ; **************************************************************
+    ; HANDLE MOVEMENT
     ; Do we want to move left?
 .norot
     ldh a, [hLeftState]
@@ -940,8 +1158,7 @@ FieldProcess::
     ldh [hWantX], a
     jr .trymove
 
-
+    ; Do we want to move right?
-    ; Want right?
 .wantright
     ldh a, [hRightState]
     cp a, 1
@@ -956,7 +1173,6 @@ FieldProcess::
     inc a
     ldh [hWantX], a
 
-
     ; Try the movement.
 .trymove
     ldh a, [hCurrentPieceY]
@@ -973,6 +1189,8 @@ FieldProcess::
     ldh [hCurrentPieceX], a
 
 
+    ; **************************************************************
+    ; HANDLE LOCKING
     ; Are we grounded?
 .donemanipulating
     ldh a, [hCurrentPieceY]
@@ -1011,18 +1229,32 @@ FieldProcess::
     ldh [hCurrentLockDelayRemaining], a
     ; If we're out of lock delay, play a sound.
     cp a, 0
-    jr nz, .draw
+    jr nz, .forcelockmaybe
     call SFXKill
     ld a, SFX_LOCK
     call SFXEnqueue
     jr .draw
 
+    ; TGM3 sometimes forces a piece to immediately lock.
+.forcelockmaybe
+    ldh a, [hLockDelayForce]
+    cp a, $FF
+    jr nz, .draw
+    xor a, a
+    ldh [hCurrentLockDelayRemaining], a
+    call SFXKill
+    ld a, SFX_LOCK
+    call SFXEnqueue
+    jr .draw
+
+    ; If we weren't grounded, reset the lock delay.
 .notgrounded
-    ; Otherwise reset the lock delay.
     ldh a, [hCurrentLockDelay]
     ldh [hCurrentLockDelayRemaining], a
 
 
+    ; **************************************************************
+    ; HANDLE DRAWING
     ; Draw the piece.
 .draw
     ; If the gravity is <= 1G, draw a ghost piece.

src/include/globals.asm

@@ -164,6 +164,9 @@ DEF MODE_TGM2           EQU 1
 DEF MODE_TGM3           EQU 2
 DEF MODE_HELL           EQU 3
 DEF MODE_EASY           EQU 4
+DEF MODE_TGW2           EQU 5
+DEF MODE_TGW3           EQU 6
+DEF MODE_EAWY           EQU 7
 
 
 ENDC

src/res/tiles.inc

@@ -432,18 +432,18 @@ Tiles::
     DB $8A,$00,$EA,$00,$00,$00,$00,$00
     DB $00,$00,$6A,$00,$8A,$00,$44,$00
     DB $24,$00,$C4,$00,$00,$00,$00,$00
-    DB $00,$00,$AA,$00,$AA,$00,$44,$00
+    DB $00,$00,$EE,$00,$48,$00,$4A,$00
-    DB $AA,$00,$AA,$00,$00,$00,$00,$00
+    DB $4A,$00,$4E,$00,$00,$00,$00,$00
-    DB $00,$00,$AA,$00,$AA,$00,$44,$00
+    DB $00,$00,$AC,$00,$A2,$00,$A4,$00
-    DB $AA,$00,$AA,$00,$00,$00,$00,$00
+    DB $E8,$00,$AE,$00,$00,$00,$00,$00
-    DB $00,$00,$AA,$00,$AA,$00,$44,$00
+    DB $00,$00,$EE,$00,$48,$00,$4A,$00
-    DB $AA,$00,$AA,$00,$00,$00,$00,$00
+    DB $4A,$00,$4E,$00,$00,$00,$00,$00
-    DB $00,$00,$AA,$00,$AA,$00,$44,$00
+    DB $00,$00,$AC,$00,$A2,$00,$A4,$00
-    DB $AA,$00,$AA,$00,$00,$00,$00,$00
+    DB $E2,$00,$AC,$00,$00,$00,$00,$00
-    DB $00,$00,$AA,$00,$AA,$00,$44,$00
+    DB $00,$00,$E4,$00,$8A,$00,$CE,$00
-    DB $AA,$00,$AA,$00,$00,$00,$00,$00
+    DB $8A,$00,$EA,$00,$00,$00,$00,$00
-    DB $00,$00,$AA,$00,$AA,$00,$44,$00
+    DB $00,$00,$AA,$00,$AA,$00,$A4,$00
-    DB $AA,$00,$AA,$00,$00,$00,$00,$00
+    DB $E4,$00,$A4,$00,$00,$00,$00,$00
     DB $7C,$7C,$42,$42,$41,$41,$5D,$48
     DB $6E,$4C,$5B,$4A,$79,$49,$00,$00
     DB $68,$58,$58,$68,$68,$58,$48,$78
@@ -508,30 +508,30 @@ Tiles::
     DB $8A,$8A,$EA,$EA,$00,$00,$00,$00
     DB $00,$00,$6A,$6A,$8A,$8A,$44,$44
     DB $24,$24,$C4,$C4,$00,$00,$00,$00
-    DB $00,$00,$AA,$AA,$AA,$AA,$44,$44
+    DB $00,$00,$EE,$EE,$48,$48,$4A,$4A
-    DB $AA,$AA,$AA,$AA,$00,$00,$00,$00
+    DB $4A,$4A,$4E,$4E,$00,$00,$00,$00
-    DB $00,$00,$AA,$AA,$AA,$AA,$44,$44
+    DB $00,$00,$AC,$AC,$A2,$A2,$A4,$A4
-    DB $AA,$AA,$AA,$AA,$00,$00,$00,$00
+    DB $E8,$E8,$AE,$AE,$00,$00,$00,$00
-    DB $00,$00,$AA,$AA,$AA,$AA,$44,$44
+    DB $00,$00,$EE,$EE,$48,$48,$4A,$4A
-    DB $AA,$AA,$AA,$AA,$00,$00,$00,$00
+    DB $4A,$4A,$4E,$4E,$00,$00,$00,$00
-    DB $00,$00,$AA,$AA,$AA,$AA,$44,$44
+    DB $00,$00,$AC,$AC,$A2,$A2,$A4,$A4
-    DB $AA,$AA,$AA,$AA,$00,$00,$00,$00
+    DB $E2,$E2,$AC,$AC,$00,$00,$00,$00
-    DB $00,$00,$AA,$AA,$AA,$AA,$44,$44
+    DB $00,$00,$E4,$E4,$8A,$8A,$CE,$CE
-    DB $AA,$AA,$AA,$AA,$00,$00,$00,$00
+    DB $8A,$8A,$EA,$EA,$00,$00,$00,$00
-    DB $00,$00,$AA,$AA,$AA,$AA,$44,$44
+    DB $00,$00,$AA,$AA,$AA,$AA,$A4,$A4
-    DB $AA,$AA,$AA,$AA,$00,$00,$00,$00
+    DB $E4,$E4,$A4,$A4,$00,$00,$00,$00
-    DB $00,$00,$00,$00,$00,$00,$00,$00
+    DB $00,$00,$00,$00,$A0,$A0,$A0,$A0
-    DB $00,$00,$00,$00,$00,$00,$00,$00
+    DB $A0,$A0,$A0,$A0,$48,$48,$00,$00
-    DB $FF,$00,$FF,$00,$FF,$00,$FF,$00
+    DB $00,$00,$00,$00,$C4,$C4,$2A,$2A
-    DB $FF,$00,$FF,$00,$FF,$00,$FF,$00
+    DB $4A,$4A,$8A,$8A,$E4,$E4,$00,$00
-    DB $00,$FF,$00,$FF,$00,$FF,$00,$FF
+    DB $00,$00,$00,$00,$CC,$CC,$22,$22
-    DB $00,$FF,$00,$FF,$00,$FF,$00,$FF
+    DB $4C,$4C,$82,$82,$EC,$EC,$00,$00
-    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
+    DB $00,$00,$00,$00,$44,$44,$CA,$CA
-    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
+    DB $4A,$4A,$4A,$4A,$E4,$E4,$00,$00
-    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
+    DB $00,$00,$00,$00,$CC,$CC,$22,$22
-    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
+    DB $44,$44,$88,$88,$EE,$EE,$00,$00
-    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
+    DB $00,$00,$00,$00,$04,$04,$0A,$0A
-    DB $FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF
+    DB $0E,$0E,$0A,$0A,$0A,$0A,$00,$00
 TilesEnd::
 
 

src/res/title_map.inc

@@ -22,7 +22,7 @@ DEF TITLE_MAP_INC EQU 1
 SECTION "Title Screen Tilemap", ROM0
 TitleScreenTilemap::
     DB $01,$01,$01,$01,$01,$01,$01,$01,$01,$01
-    DB $01,$01,$01,$01,$01,$01,$01,$01,$01,$01
+    DB $01,$01,$01,$01,$FA,$FB,$FC,$FD,$FE,$FF
     DB $01,$01,$01,$01,$01,$01,$01,$01,$01,$01
     DB $01,$01,$01,$01,$01,$01,$01,$01,$01,$01
     DB $01,$01,$01,$01,$01,$01,$01,$01,$01,$01

src/rng.asm

@@ -24,10 +24,17 @@ INCLUDE "globals.asm"
 
 SECTION "High RNG Variables", HRAM
 hRNGSeed:      ds 4
-hPieceHistory: ds 6
+hPieceHistory: ds 4
 hNextPiece::   ds 1
 
 
+SECTION "TGM3 RNG Variables", WRAM0
+wTGM3Bag:             ds 35
+wTGM3Droughts:        ds 7
+wTGM3GeneratedIdx:    ds 1
+wTGM3WorstDroughtIdx: ds 1
+
+
 section "RNG Functions", ROM0
 RNGInit::
     ; Do some bit fuckery on the seed using the gameboy's free-running timers.
@@ -47,18 +54,41 @@ RNGInit::
     xor a, [hl]
     ldh [hRNGSeed+3], a
 
-    ; Initialize the next history.
+    ; TGM3 vars
+    ld de, sTGM3Bag
+    ld hl, wTGM3Bag
+    ld bc, 35
+    call UnsafeMemCopy
+    ld de, sTGM3Droughts
+    ld hl, wTGM3Droughts
+    ld bc, 7
+    call UnsafeMemCopy
+
+    ; If we're in HELL mode, we don't care about anything but a random piece to start with.
+    ldh a, [hSimulationMode]
+    cp a, MODE_HELL
+    jr nz, .complexinit
+    call Next7Piece
+    ld [hNextPiece], a
+    ret
+
+    ; Otherwise do complex init.
+.complexinit
     ld a, PIECE_Z
     ldh [hPieceHistory], a
     ldh [hPieceHistory+1], a
-    ldh [hPieceHistory+4], a
+    ldh [hPieceHistory+2], a
-    ldh [hPieceHistory+5], a
+    ldh [hPieceHistory+3], a
+
+    ldh a, [hSimulationMode]
+    cp a, MODE_TGM1
+    jr z, :+
     ld a, PIECE_S
     ldh [hPieceHistory+2], a
     ldh [hPieceHistory+3], a
 
     ; Get the first piece and make sure it's not Z, S or O.
-:   call NextPiece
+:   call Next7Piece
     cp a, PIECE_Z
     jr z, :-
     cp a, PIECE_S
@@ -66,99 +96,296 @@ RNGInit::
     cp a, PIECE_O
     jr z, :-
 
-    ; Store it.
+    ; Save the generated piece and put it in the history.
     ldh [hPieceHistory], a
     ld [hNextPiece], a
     ret
 
 
-GetNextPiece::
+    ; Shift the generated piece into the history and save it.
-:   ldh a, [hSimulationMode] ; Hell?
+ShiftHistory:
-    cp a, MODE_HELL
-    jr nz, :+
-    call NextPiece
-    jr .donerolling
-
-:   ldh a, [hSimulationMode] ; TGM1?
-    cp a, MODE_TGM1
-    jr nz, :+
-    ld a, 5
-    ld e, a
-    jr .rollloop
-
-:   ldh a, [hSimulationMode] ; EASY?
-    cp a, MODE_EASY
-    jr nz, :+
-    ld a, 0
-    ld e, a
-    jr .rollloop
-
-:   ld a, 7 ; TGM2/3.
-    ld e, a
-
-.rollloop
-    dec e
-    jr z, .donerolling
-
-    call NextPiece
-    ld hl, hPieceHistory
-    cp a, [hl]
-    jr z, .rollloop
-    inc hl
-    cp a, [hl]
-    jr z, .rollloop
-    inc hl
-    cp a, [hl]
-    jr z, .rollloop
-    inc hl
-    cp a, [hl]
-    jr z, .rollloop
-
-    ; Are we in TGM3 or EASY mode?
-    ld b, a
-    ldh a, [hSimulationMode]
-    cp a, MODE_TGM3
-    jr z, .6hist
-    cp a, MODE_EASY
-    jr z, .6hist
-    jr .donerolling ; If not, we're done rolling.
-
-    ; If we are, extend the history by 2.
-.6hist
-    ld a, b
-    inc hl
-    cp a, [hl]
-    jr z, .rollloop
-    inc hl
-    cp a, [hl]
-    jr z, .rollloop
-
-.donerolling
     ldh [hNextPiece], a
-    ld b, a
-    ldh a, [hPieceHistory+4]
-    ldh [hPieceHistory+5], a
-    ldh a, [hPieceHistory+3]
-    ldh [hPieceHistory+4], a
     ldh a, [hPieceHistory+2]
     ldh [hPieceHistory+3], a
     ldh a, [hPieceHistory+1]
     ldh [hPieceHistory+2], a
     ldh a, [hPieceHistory]
     ldh [hPieceHistory+1], a
-    ld a, b
+    ldh a, [hNextPiece]
     ldh [hPieceHistory], a
     ret
 
 
-NextPiece:
+    ; A random piece. Get fucked.
-    call NextByte
+GetNextHellPiece:
+    call Next7Piece
+    ldh [hNextPiece], a
+    ret
+
+
+    ; 4 history, 4 rerolls.
+GetNextTGM1Piece:
+    ld a, 5
+    ld e, a
+
+:   dec e
+    jr z, :+
+
+    call Next7Piece
+    ld hl, hPieceHistory
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+
+:   jr ShiftHistory
+
+
+    ; 4 history, 6 rerolls.
+GetNextTGM2Piece:
+    ld a, 7
+    ld e, a
+
+:   dec e
+    jr z, :+
+
+    call Next7Piece
+    ld hl, hPieceHistory
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+
+:   jr ShiftHistory
+
+
+    ; 4 History, (basically) infinite rerolls.
+GetNextEasyPiece:
+    ld a, 0
+    ld e, a
+
+:   dec e
+    jr z, :+
+
+    call Next7Piece
+    ld hl, hPieceHistory
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+
+:   jr ShiftHistory
+
+
+    ; TGM3 mode... It's complex.
+GetNextTGM3Piece:
+    ld a, 7
+    ld e, a
+
+:   dec e
+    jr z, :+
+
+    ; Get a random index into the 35bag
+    call Next35Piece
+    ld [wTGM3GeneratedIdx], a
+
+    ; Fetch the piece from the 35bag.
+    ld c, a
+    xor a, a
+    ld b, a
+    ld hl, wTGM3Bag
+    add hl, bc
+    ld a, [hl]
+
+    ; Is it in the history?
+    ld hl, hPieceHistory
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+    inc hl
+    cp a, [hl]
+    jr z, :-
+
+    ; We have a piece. Save it.
+:   call ShiftHistory
+
+    ; Increment all drought counters.
+:   ld hl, wTGM3Droughts
+    inc [hl]
+    inc hl
+    inc [hl]
+    inc hl
+    inc [hl]
+    inc hl
+    inc [hl]
+    inc hl
+    inc [hl]
+    inc hl
+    inc [hl]
+    inc hl
+    inc [hl]
+
+    ; Set the drought of our most recently drawn piece to 0.
+:   ldh a, [hCurrentPiece]
+    ld c, a
+    xor a, a
+    ld b, a
+    ld hl, wTGM3Droughts
+    add hl, bc
+    ld [hl], a
+
+    ; We pick an arbitrary piece to have the worst drought.
+:   call Next7Piece
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; And then save that drought in e.
+    ld c, a
+    xor a, a
+    ld b, a
+    ld hl, wTGM3Droughts
+    add hl, bc
+    ld e, [hl]
+
+    ; Is idx 0 worse?
+:   ld hl, wTGM3Droughts
+    ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 0
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; Is idx 1 worse?
+:   ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 1
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; Is idx 2 worse?
+:   ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 2
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; Is idx 3 worse?
+:   ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 3
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; Is idx 4 worse?
+:   ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 4
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; Is idx 5 worse?
+:   ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 5
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; Is idx 6 worse?
+:   ld a, [hl+]
+    cp a, e
+    jr z, :+    ; Same.
+    jr c, :+    ; Nope.
+    ld e, a
+    ld a, 6
+    ld [wTGM3WorstDroughtIdx], a
+
+    ; We now have the worst drought index as well as the slot in the bag that needs to be replaced.
+:   ld a, [wTGM3GeneratedIdx]
+    ld c, a
+    xor a, a
+    ld b, a
+    ld hl, wTGM3Bag
+    add hl, bc
+    ld a, [wTGM3WorstDroughtIdx]
+
+    ; Replace that slot.
+    ld [hl], a
+    ret
+
+
+GetNextPiece::
+    ldh a, [hSimulationMode]
+    cp a, MODE_HELL
+    jp z, GetNextHellPiece
+    cp a, MODE_TGM1
+    jp z, GetNextTGM1Piece
+    cp a, MODE_TGM2
+    jp z, GetNextTGM2Piece
+    cp a, MODE_TGW2
+    jp z, GetNextTGM2Piece
+    cp a, MODE_TGM3
+    jp z, GetNextTGM3Piece
+    cp a, MODE_TGW3
+    jp z, GetNextTGM3Piece
+    cp a, MODE_EASY
+    jp z, GetNextEasyPiece
+    cp a, MODE_EAWY
+    jp z, GetNextEasyPiece
+
+
+Next35Piece:
+:   call NextByte
+    and a, $3F
+    cp a, 35
+    jr nc, :-
+    ret
+
+
+Next7Piece:
+:   call NextByte
     and a, $07
     cp a, 7
-    ret nz
+    jr nc, :-
-    dec a
     ret
 
+
 NextByte:
     ; Load seed
     ld hl, hRNGSeed+3

src/state_title.asm

@@ -95,7 +95,7 @@ TitleEventLoopHandler::
     jr nz, :+
     ldh a, [hSimulationMode]
     inc a
-    cp a, 5
+    cp a, 8
     jr nz, .write
     xor a, a
 .write