; *** S P L A T F O R M 2 6 0 0 *** ; Atari 2600 version of the 2002 Minigames Competition ; 1K winning game by Robin Harbron ; (C)2003 - Thomas Jentzsch ; TODOs: ; + better collision detection ; o improved platform generation (TODO: various platform offsets?) ; + P0 easy = non-random, hard = random ; x animated Bouncy (no space!) ; o scoring (TODO: more points at higher levels?) ; + sounds ; + variable x-speed ; + lifes ; + lifes display at left ; + wait at start (firebutton) ; + loose life at 0 points ; + high score ; - show version number at start (0 points before start) ; + limit minimum platform density (table?) ; x no flicker at RESET/next level (level generation is a problem) ; ? visual end of level ; + smooth scrolling ; + scroll in new playfield ; + lenghtLst ; o new bouncing physics (TODO: different sounds?) ; + P1 easy = height (new), hard = const (old) processor 6502 include vcs.h ;=============================================================================== ; A S S E M B L E R - S W I T C H E S ;=============================================================================== VERSION = $0101 BASE_ADR = $f800 DEBUG = 0 INVINCIBLE = 0 ; invincible Bouncy UNLIMITED = 0 NTSC = 1 LARGE_BOUNCY = 1 ; (+ ?) Bouncy size: 7x12 or 5x8 MULTI_COLOR = 1 ; (+12) multiple colors for Bouncy RANDOM = 1 ; (+13) RIGHT_SCORE = 1 ; ( +2) NEW_BUMP = 1 ; ( +7) FLICKER = 1 ; ( +4) background flicker when losing life ;=============================================================================== ; C O N S T A N T S ;=============================================================================== SCW = 160 DIGIT_HEIGHT = 9 NUM_ROWS = 18 ROW_H = 8 KERNEL_TOP = 45 ; = 45 KERNEL_H = NUM_ROWS * ROW_H + KERNEL_TOP ; = 189 ;total: DIGIT_HEIGHT + 2 + KERNEL_H = 200 IF LARGE_BOUNCY BOUNCY_H = 12 BOUNCY_W = 7 ELSE BOUNCY_H = 8 BOUNCY_W = 5 ENDIF BOUNCY_Y = KERNEL_H-BOUNCY_H IF NTSC BOUNCY_COL = $1c ; yellow BOUNCY_COL_STOP = $3a ; orange BOUNCY_COL_BACK = $46 ; red SCORE_COLOR = $0a ; white HISCORE_COLOR = $46 ; red ELSE BOUNCY_COL = $2e ; yellow BOUNCY_COL_STOP = $4a ; orange BOUNCY_COL_BACK = $66 ; red SCORE_COLOR = $0a ; white HISCORE_COLOR = $66 ; red ENDIF RAND_EOR_8 = $b4 ;$b2; $e7; $c3 RAND_SEED = $-1 ; (unused?) ; difficulty speed parameters: GRAVITY = 55 BUMP = $550 ;GRAVITY = 50 ;BUMP = $510 ;GRAVITY = 45 ;BUMP = $4d0 SPEED_X = $18 SPEED_MAX_X = 2 BOUNCY_MIN_X = 8 BOUNCY_MAX_X = SCW*3/8-BOUNCY_W/2 ; platform generation parameters: MAX_PLATFORM = 8-1 ; maximum platform length FACTOR = (255+NUM_ROWS)/(NUM_ROWS*2) ; 7.58 = 7 (~1/18/2) INIT_SPEED = 2 ; initial scrolling speed ;DENSITY = $2c0 ; initial plattfrom density ($2d0) DENSITY = ($3c)*(FACTOR+(MAX_PLATFORM+1)/2) ; initial plattfrom density DENSITY_MASK = >DENSITY|>DENSITY/2 ADVANCE = 16 ; advance of difficulty (1/ADVANCE) NUM_LEVEL = 10 ;=============================================================================== ; Z P - V A R I A B L E S ;=============================================================================== SEG.U variables ORG $80 tmpVars ds 9 tmpVar = tmpVars tmpVar2 = tmpVars+1 tmpVar3 = tmpVars+2 frameCnt .byte random .byte xPosLst ds NUM_ROWS hmPosLst ds NUM_ROWS pfLst ds NUM_ROWS lenghtLst ds NUM_ROWS ; saves *1* byte ySpeed ds 2 ySpeedHi = ySpeed ySpeedLo = ySpeed+1 xSpeed ds 2 xSpeedHi = xSpeed xSpeedLo = xSpeed+1 ;cxRowY .byte ; 0..NUM_ROWS-1 sound .byte levelCnt .byte yBouncy ds 2 yBouncyHi = yBouncy yBouncyLo = yBouncy+1 xBouncy ds 2 xBouncyHi = xBouncy xBouncyLo = xBouncy+1 scrollIn .byte scrollSum .byte pfSum ds 2 pfSumHi = pfSum pfSumLo = pfSum+1 end_of_next = . ; variables not resetted for next level: level .byte score ds 2 scoreHi = score scoreLo = score+1 end_of_reset = . compMode .byte ; random mode? ; variables initialized at start of game: initVars = . saveRandom .byte colorP1 .byte ; cccc111. bits lifes .byte cxRowY .byte ; 0..NUM_ROWS-1 scoreMax ds 2 scoreMaxHi = scoreMax scoreMaxLo = scoreMax+1 NUM_INIT = . - initVars ECHO "*** RAM: ", ., " ***" ;=============================================================================== ; M A C R O S ;=============================================================================== MAC DEBUG_BRK IF DEBUG brk ; ENDIF ENDM MAC BIT_B .byte $24 ENDM MAC BIT_W .byte $2c ; 4 cylces ENDM MAC SLEEP IF {1} = 1 ECHO "ERROR: SLEEP 1 not allowed !" END ENDIF IF {1} & 1 nop $00 REPEAT ({1}-3)/2 nop REPEND ELSE REPEAT ({1})/2 nop REPEND ENDIF ENDM MAC CHECKPAGE IF >. != >{1} ECHO "" ECHO "ERROR: different pages! (", {1}, ",", ., ")" ECHO "" ERR ENDIF ENDM MAC DEC2BCD IF {1} > 99 ECHO "ERROR: Value too large for BCD! (", {1}, ")" ERR ENDIF .byte ({1}) / 10 << 4 | ({1}) % 10 ENDM ;=============================================================================== ; R O M - C O D E ;=============================================================================== SEG Bank0 ORG BASE_ADR ;--------------------------------------------------------------- Start SUBROUTINE ;--------------------------------------------------------------- ; cart inserted cld ldx #NUM_INIT-1 ;--------------------------------------------------------------- Reset: ;--------------------------------------------------------------- ; RESET pressed .loopInit: lda InitTbl,x sta initVars,x dex bpl .loopInit IF RANDOM lda SWCHB sta compMode ENDIF ldx #end_of_reset ;--------------------------------------------------------------- StartLevel: ;--------------------------------------------------------------- ; (re)start level ; x contains number of resetted variables lda #0 .clearLoop: dex txs pha bne .clearLoop IF DEBUG lda #$80 sta COLUBK lda #$04 sta COLUPF ENDIF ;--------------------------------------------------------------- GameInit SUBROUTINE ;--------------------------------------------------------------- ; lda #BOUNCY_Y ; sta yBouncy ; dec yBouncy lda saveRandom sta random lda #(SCW-8)/INIT_SPEED sta scrollIn ; lda #$10 ; sta scrollSum .byte $a9 DEC2BCD 100-(SCW-8)/4 ; add missing ~60 points (total: 100 points) jsr Add16_ScorePos ; lda #$01 ; sta scoreHi ; lsr ; sta scoreLo ;GameInit ;; lda #%100000 ;; sta CTRLPF ; lda #$30 ; sta HMBL ; sta WSYNC ; sta HMOVE ;; lda #157+3 ;; ldx #4 ;; jsr XPosObject ; sta WSYNC ; sta HMCLR ;--------------------------------------------------------------- OverScan SUBROUTINE ;--------------------------------------------------------------- lda #36-6 ; 2 sta TIM64T ; 4 stx GRP0 ; 3 @02 stx VDELP1 ; 3 ; *** handle collisions: *** ; lda #0 ; sta COLUBK ; calculate old row: ; sec ; almost doesn't matter lda yBouncyLo ; C=1! sbc ySpeedLo lda yBouncyHi sbc ySpeedHi sbc #ROW_H*2 ; C=0! bcc .skipCollision ; no, skip sbc cxRowY ; was previous row above? bcc .skipCollision ; no, skip ; *** bump *** lda #BUMP bit compMode ; constant bump mode? bmi .contBump ; yes sbc ySpeedLo ; no, 50% additional bump for previous height tay txa sbc ySpeedHi lsr tax tya ror .contBump: sta ySpeedLo stx ySpeedHi ; start bouncing sound: ; clc ; adc #5 ; sta sound lda #$0c sta AUDC0 sta sound lda #$95 ; -5 points ldy #$99 jsr Add16_Score bcc .resetScore ; score below zero, loose life! .skipCollision: ldy #-1 ; reinitialize collision variable sty cxRowY ; *** play sounds: *** lax sound beq .skipSound bpl .bounce dex asl bpl .falling asl ; falling sound over? beq .nextLevel stx AUDV0 lda #$04 sta AUDC0 txa bne .setAudF0 ; goto next level .nextLevel: inc level ; yes, increase level,... lda colorP1 ; ...calculate new level color,... adc #$2f ; C=1! (color repeats after 16 levels) sta colorP1 lda random ; ...save new initial random value,... sta saveRandom .startLevel: ldx #end_of_next ; ...and start new level bne StartLevel ; 3 ; make falling sound: .falling: bne .contFalling ; loose one life: IF UNLIMITED = 0 lsr lifes lsr lifes ; any more lifes? bne .startLevel ; yes, restart current level ; no, game over!!! ELSE beq .startLevel ENDIF jsr CheckHigh ; new high score? bcc .skipHigh stx scoreMaxLo sty scoreMaxHi .skipHigh: ldx #0 stx scrollIn .contFalling: txa IF FLICKER sta COLUBK ENDIF lsr lsr sta AUDV0 lda #$03 sta AUDC0 lda #$0c bne .setAudF0 ;--------------------------------------- .resetScore: ; set score to zero lda #0 sta scoreLo sta scoreHi .looseLife: lda #$b8 ; start dying sound ($0b..$00) sta sound .endMoveJmp: jmp .endMove ;--------------------------------------- ; make bouncing sound: .bounce: dex txa sta AUDV0 adc #$13 ; C=1! .setAudF0: sta AUDF0 stx sound .skipSound: ; *** check RESET switch: *** ldx #NUM_INIT-3 ; number of initialized variables lsr SWCHB bcc .doReset ; brk! ; *** wait at start of level: *** lda scrollIn bmi .skipWait bne .endMoveJmp bit INPT4 bmi .endMoveJmp lda lifes beq .doReset ; brk! dec scrollIn ; .skipWait: bit sound bmi .endMoveJmp ; *** move Bouncy vertically: *** ; ldy #-1 lda #-GRAVITY ; y = -1! ldx #ySpeed jsr Add16 tay lda ySpeedLo ldx #yBouncy jsr Add16 ; check for falling down: IF INVINCIBLE = 0 cmp #-18 bcs .looseLife ELSE clc ENDIF ; lda #BOUNCY_H+ROW_H-3-1 ; -> just above bottom row ; lda #KERNEL_H-1 ; -> directly at top ; lda #-1 ; sta yBouncyHi ; *** horizontal movement: *** ; *** move Bouncy horizontally: *** .doReset = . + 1 ; check joystick: ldy #0 ; brk! lda #SPEED_X bit SWCHA bpl .addSpeedX tya bvs .addSpeedX dey lda #-SPEED_X ; brakes faster than accelerating .addSpeedX: ldx #xSpeed jsr Add16 ; friction: asl ; positive or negative speed? ldy #0 lda #SPEED_X/3 bcs .subSpeedX dey lda #-SPEED_X/3 .subSpeedX: jsr Add16 ; x = Zero ; 2 sta .ptrScore,x ; 4 sta .ptrScore+4,x ; 4 dex ; 2 sty .tmpY ; 3 lda score,y ; 4 pha ; 3 lsr ; 2 lsr ; 2 lsr ; 2 lsr ; 2 tay ; 2 lda DigitTbl,y ; 4 sta .ptrScore,x ; 4 pla ; 4 and #$0f ; 2 tay ; 2 lda DigitTbl,y ; 4 sta .ptrScore+4,x ; 4 ldy .tmpY ; 3 dey ; 2 dex ; 2 bpl .loopScore ; 2³ ;total: 133 .waitTim: lda INTIM bne .waitTim ; sta VBLANK ;=============================================== ldy #DIGIT_HEIGHT .loopDigits: sta WSYNC ;--------------------------------------- ldx #NUM_ROWS ; 2 stx .rows ; 3 lda lifes ; 3 sta GRP0 ; 3 @11 lda (.ptrScore+4),y ; 5 sta GRP1 ; 3 @19 IF RIGHT_SCORE lda (.ptrScore,x) ; 6 = SLEEP 6 ENDIF lax (.ptrScore+6),y ; 5 lda (.ptrScore),y ; 5 sta GRP0 ; 3 @38 lda (.ptrScore+2),y ; 5 sta GRP0 ; 3 @46 stx GRP1 ; 3 @49 dey ; 2 bne .loopDigits ; 2³ @53³ sty GRP1 ; 3 sty GRP0 ; 3 = 6 lda xBouncy ; 3 jsr XPosObject0 ; 6 = 9 @68/@09 lda #Y & DENSITY_MASK) Y2 SET (Y2 * (ADVANCE-1) + ADVANCE/2)/ADVANCE REPEND InitTbl: .byte RAND_SEED ; saveRandom .byte $2e ; colorP1 .byte %01010101 ; lifes (4 lifes, only three are shown!) .byte -1 ; cxRowY .byte >VERSION ; scoreMaxHi .byte