277 lines
6.2 KiB
NASM
277 lines
6.2 KiB
NASM
; -----------------------------------------------------------
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; menu.asm - full-screen menu card: big RABBIT VS SCOOTER
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; logo flanked by two hopping rabbits, and a four-item menu:
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; single player / multiplayer / credits / story
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; (joystick up/down + fire; the s, m, c, t shortcut keys and
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; the 1 / 2 player-mode keys all start their line at once)
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; -----------------------------------------------------------
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menu_init:
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lda #BLACK ; the menu plays on a black screen
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sta bg_top
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sta bg_bot
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jsr clear_screen
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+prbig 1, 8, RED, txt_rabbit, 6
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+prtext 6, 19, YELLOW, txt_vs, 2
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+prbig 7, 6, WHITE, txt_scooter, 7
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lda mp_mode ; cursor starts on the last played mode
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sta menusel
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lda #1 ; a letter still held from the previous
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sta lkheld ; screen must be released first
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; decoration: white rabbits flank the logo (sprites 1-2,
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; double-sized), the red scooter waits at the bottom
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lda #RED
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sta SPR_COL
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lda #WHITE
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sta SPR_COL+1
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sta SPR_COL+2
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lda #30 ; left rabbit
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sta SPRPOS+2
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lda #58
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sta SPRPOS+3
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sta SPRPOS+5
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lda #34 ; right rabbit: x = 290, MSB below
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sta SPRPOS+4
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lda #%00000100
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sta SPR_MSBX
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lda #%00000110 ; both rabbits double-sized
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sta SPR_XEX
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sta SPR_YEX
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lda #%00000110 ; only the two flanking rabbits
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sta SPR_EN
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+setupd menu_update
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rts
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menu_update:
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; hop the flanking rabbits through the big frames,
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; half a cycle apart
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lda framectr
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lsr
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lsr
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lsr
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and #3
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sta rtmp
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clc
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adc #SPRP_BIG
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sta SPRPTR+1
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lda rtmp
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clc
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adc #2
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and #3
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clc
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adc #SPRP_BIG
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sta SPRPTR+2
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; joystick up/down steps the cursor (edge detected)
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jsr read_joy
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lda joyb
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and #3
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beq mu_udrel
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lda udheld
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bne mu_udend
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lda #1
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sta udheld
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lda joyb
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and #1 ; up
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beq mu_down
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lda menusel
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beq mu_udend
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dec menusel
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lda #SFX_CURSOR
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jsr sfx_play
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jmp mu_udend
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mu_down:
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lda menusel
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cmp #MENU_ITEMS-1
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beq mu_udend
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inc menusel
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lda #SFX_CURSOR
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jsr sfx_play
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jmp mu_udend
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mu_udrel:
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lda #0
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sta udheld
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mu_udend:
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; letter keys pick a line and open it right away (edge
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; detected); skipped while joystick 1 fire is down, because
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; it grounds the same row line the 'm' and 'c' keys sit on
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lda #$ff
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sta CIA1_PA
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lda CIA1_PB
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and #$10
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beq mu_keydone
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ldx #$ff ; no letter key seen yet
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lda #$fd ; 's': keyboard column 1, row bit 5
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sta CIA1_PA
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lda CIA1_PB
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and #$20
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bne mu_nos
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ldx #0
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mu_nos:
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lda #$ef ; 'm': keyboard column 4, row bit 4
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sta CIA1_PA
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lda CIA1_PB
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and #$10
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bne mu_nom
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ldx #1
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mu_nom:
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lda #$fb ; 'c': keyboard column 2, row bit 4
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sta CIA1_PA
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lda CIA1_PB
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and #$10
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bne mu_noc
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ldx #2
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mu_noc:
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lda CIA1_PB ; column 2 still selected
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and #$40 ; 't': keyboard column 2, row bit 6
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bne mu_not
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ldx #3
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mu_not:
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cpx #$ff
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beq mu_lkup ; no letter key held
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lda lkheld
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bne mu_lkend ; still held from an earlier frame
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inc lkheld
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stx menusel
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jmp menu_go
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mu_lkup:
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lda #0
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sta lkheld
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mu_lkend:
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; the 1 / 2 keys pick and start right away (edge detected)
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lda #$7f ; keyboard column 7: '1' = bit 0, '2' = bit 3
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sta CIA1_PA
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lda CIA1_PB
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and #$09
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cmp #$09
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beq mu_keyup ; neither key held
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ldx k12held
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bne mu_keydone ; still held from an earlier frame
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inx
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stx k12held
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and #$01
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bne mu_key2
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lda #0
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sta menusel
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jmp menu_go
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mu_key2:
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lda #1
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sta menusel
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jmp menu_go
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mu_keyup:
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lda #0
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sta k12held
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mu_keydone:
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; footer: both control lines always visible
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+prtext 22, 9, LGREY, txt_info, 21
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+prtext 23, 9, LGREY, txt_info2, 21
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; the menu items: the picked line is yellow
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ldx #0
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mm_items:
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txa
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pha
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jsr draw_mitem
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pla
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tax
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inx
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cpx #MENU_ITEMS
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bne mm_items
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; blinking '>' cursor in front of the picked line
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lda #$20
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sta SCREEN+14*40+12
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sta SCREEN+16*40+12
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sta SCREEN+18*40+12
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sta SCREEN+20*40+12
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lda framectr
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and #16
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bne mu_start
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ldx menusel
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lda mcur_lo,x
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sta scrlo
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lda mcur_hi,x
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sta scrhi
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ldy #0
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lda #62 ; '>'
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sta (scrlo),y
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lda scrhi
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clc
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adc #$d4 ; same cell in color RAM
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sta scrhi
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lda #YELLOW
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sta (scrlo),y
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mu_start:
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; fire or space opens the picked line
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jsr start_edge
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beq mu_done
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menu_go:
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lda #SFX_SELECT
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jsr sfx_play
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lda menusel
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cmp #2
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beq mg_credits
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cmp #3
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beq mg_story
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sta mp_mode ; item 0 / 1 doubles as the player count
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jmp play_init ; its rts returns to the main loop
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mg_credits:
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jmp credits_init
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mg_story:
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jmp story_init
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mu_done:
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rts
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; ---- draw menu item X, yellow when it is the picked one ----
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draw_mitem:
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lda mitem_lo,x
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sta txtlo
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lda mitem_hi,x
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sta txthi
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lda mitem_row,x
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sta prow
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lda #14
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sta pcol
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lda mitem_len,x
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sta plen
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lda #WHITE
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cpx menusel
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bne dm_store
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lda #YELLOW
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dm_store:
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sta pcolor
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stx rtmp ; print_text trashes X
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jsr print_text
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ldx rtmp
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ldy mitem_key,x ; recolor the shortcut letter
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lda #CYAN
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sta (collo),y
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rts
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; ---- menu tables ----
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MENU_ITEMS = 4
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mitem_lo: !byte <txt_1p, <txt_2p, <txt_credits, <txt_story
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mitem_hi: !byte >txt_1p, >txt_2p, >txt_credits, >txt_story
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mitem_key: !byte 0, 0, 0, 1 ; offset of the highlighted shortcut letter
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mitem_len: !byte 13, 11, 7, 5
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mitem_row: !byte 14, 16, 18, 20
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mcur_lo: ; cursor cells: column 12 of those rows
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!byte <(SCREEN+14*40+12), <(SCREEN+16*40+12)
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!byte <(SCREEN+18*40+12), <(SCREEN+20*40+12)
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mcur_hi:
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!byte >(SCREEN+14*40+12), >(SCREEN+16*40+12)
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!byte >(SCREEN+18*40+12), >(SCREEN+20*40+12)
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; ---- menu variables ----
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menusel: !byte 0 ; picked line: 0-3
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udheld: !byte 0 ; joystick up/down edge detection state
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lkheld: !byte 0 ; shortcut letter edge detection state
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