4cade/src/ui.attract.gr.a

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;license:MIT
;(c) 2018-2020 by 4am
;
; GR action slideshows
;
; Public functions
; - GRActionSlideshow
; - GRSingle
;
;------------------------------------------------------------------------------
; GRActionSlideshow
; display a slideshow of lo-res action screenshots
;
; in: none
; out: everything clobbered
; graphics mode set to display hi-res screen
;------------------------------------------------------------------------------
GRActionSlideshow
jsr LoadGRTransition ; load transition effect code at $6000
jsr BlankGR ; switch GR mode with initial blank screen
jsr okvs_iter ; cycle through all listed GR files
!word gSlideshowStore
!word GRActionCallback ; address of callback (called on each file)
jmp BlankHGR ; switch back to HGR mode with initial blank screen on exit
;------------------------------------------------------------------------------
; GRSingle
; display a single lo-res screenshot, with transition effect
;
; in: none
; out: everything clobbered
; graphics mode set to display hi-res screen
;------------------------------------------------------------------------------
GRSingle
+ST16 IndexedGRFilename
jsr BlankGR ; switch to GR mode with initial blank screen
jsr LoadIndexedGRFile ; load GR screen at $4000
jsr LoadGRTransition ; load transition effect code at $6000
jsr ExecuteTransitionAt6000AndWait
jmp BlankHGR ; switch back to HGR mode with initial blank screen on exit
;------------------------------------------------------------------------------
; BlankGR [private]
; clear and show GR page 1 without flickering
;
; in: none
; out: text page clobbered
; graphics mode set to display lo-res screen
;------------------------------------------------------------------------------
BlankGR
ldy #$2C ; BIT
sty PageFrom
ldx #$04
stx PageTo+2
lda #0
jsr ClearGR
bit PAGE1
bit $C056 ; set GR mode
jmp GRMode
;------------------------------------------------------------------------------
; LoadGRTransition [private]
;
; in: none
; out: all registers and flags clobbered
; $6000..$BFFF/main contains transition effect code (probably not all
; of that, but no promises)
;------------------------------------------------------------------------------
LoadGRTransition
jsr LoadIndexedFile
!word $6000
!word kGRFizzleRecord
GRRTS rts
;------------------------------------------------------------------------------
; GRActionCallback [private]
; callback called by okvs_iter on gSlideshowStore
; to load and display a single GR action screenshot
; in: A/Y contains address of filename (name only, path is always /ACTION.GR/)
; $WINDEX contains 0-based index of the current record in gSlideshowStore (word)
; out: all registers and flags clobbered
; $0800..$1EFF preserved (this contains the gSlideshowStore OKVS data)
; $2000..$BFFF clobbered by graphics data and transition code
;------------------------------------------------------------------------------
GRActionCallback
bit KBD
bmi GRRTS
+ST16 IndexedGRFilename
jsr FindGame
; if game name is not found (C will be set here), it means the game
; can't be played due to memory or joystick requirements, so we hide
; it from slideshows
bcs GRRTS
jsr LoadIndexedGRFile
jmp ExecuteTransitionAt6000AndWait
LoadIndexedGRFile
; in: caller has set IndexedGRFilename
; out: all flags & registers clobbered
jsr LoadIndexedFile ; load index file into $4600
- !word $4600
!word kGRActionIndexRecord
jsr okvs_find
!word -
IndexedGRFilename
!word $FDFD ; SMC
+ST16 @indexRecordPtr
jsr LoadIndexedFile ; load GR screenshot at $4000
!word $4000 ; because that's where the transition code expects to find it
@indexRecordPtr
!word $FDFD ; SMC
rts