;license:MIT
;(c) 2018-2021 by 4am & qkumba
;
; Super hi-res slideshows
;
; Public functions
; - SHRSlideshow
; - SHRSingle
;

;------------------------------------------------------------------------------
; SHRSlideshow
; execute a slideshow of super hi-res artwork
;
; safe to call if machine can not display super hi-res graphics (does nothing
; and exits)
;
; in:    none
; out:   everything clobbered
;        graphics mode reset to display hi-res screen, which is blank
;------------------------------------------------------------------------------
SHRSlideshow
         lda   MachineStatus         ; only show SHR on IIgs or if we have a VidHD card
         and   #SUPPORTS_SHR
         beq   SHRRTS
         jsr   LoadSHRTransition
         jsr   okvs_iter
         !word gSlideshowStore
         !word SHRArtworkCallback
         beq   jmpblank              ; always taken

;------------------------------------------------------------------------------
; SHRSingle
; display a single super hi-res artwork
;
; safe to call if machine can not display super hi-res graphics (does nothing
; and exits)
;
; in:    none
; out:   everything clobbered
;        graphics mode reset to display hi-res screen, which is blank
;------------------------------------------------------------------------------
SHRSingle
         +ST16 IndexedSHRFilename
         lda   MachineStatus         ; only show SHR on IIgs or if we have a VidHD card
         and   #SUPPORTS_SHR
         beq   SHRRTS
         jsr   BlankSHR
         jsr   LoadIndexedSHRFile
         jsr   DecompressSHR
         jsr   LoadSHRTransition
         jsr   ExecuteTransitionAtA000AndWait
jmpblank
         jmp   BlankHGR

;------------------------------------------------------------------------------
; LoadSHGRTransition [private]
; load the SHR transition effect code (currently always the same file)
;
; in:    none
; out:   all registers and flags clobbered
;        $A000..$BFFF/main contains transition effect code
;------------------------------------------------------------------------------
LoadSHRTransition
         jsr   LoadFile
         !word kFXDirectory
         !word kSFXFizzleFile
         !word $A000
SHRRTS   rts

;------------------------------------------------------------------------------
; SHRArtworkCallback [private]
; callback called by okvs_iter on gSlideshowStore
; to load and display a single SHR graphic

; in:    A/Y contains address of filename (name only, path is always /ARTWORK.SHR/)
;        $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
;        $2000..$5FFF/aux clobbered
;------------------------------------------------------------------------------
SHRArtworkCallback
         bit   KBD
         bmi   SHRRTS

         +ST16 IndexedSHRFilename
         +ST16 gLastMegaAttractGame

         jsr   FindGame
         ; if game is not found (C will be set here), it means it can't be played on
         ; this machine due to memory or joystick requirements, so we don't display
         ; it in slideshows
         bcs   SHRRTS

         jsr   BlankSHR
         jsr   LoadIndexedSHRFile
         jsr   DecompressSHR
         jmp   ExecuteTransitionAtA000AndWait

LoadIndexedSHRFile
; in:    caller has populated IndexedSHRFilename
; out:   all flags & registers clobbered
         jsr   LoadIndexedFile       ; load index file into $2000
         !word kTotalIndexFile
-        !word $2000
         !word kSHRArtworkIndexRecord

         jsr   okvs_find
         !word -
IndexedSHRFilename
         !word $FDFD                 ; SMC
         +ST16 @indexRecordPtr

         jsr   LoadIndexedFile       ; load compressed SHR artwork at $1FF8/main (not aux)
         !word kTotalDataFile
         !word $1FF8
@indexRecordPtr
         !word $FDFD                 ; SMC
         rts

;------------------------------------------------------------------------------
; BlankSHR [private]
; clear and show SHR mode without flickering
;
; in:    Machine is a IIgs or has a VidHD card that responds appropriately to
;        IIgs-specific softswitches for graphics and memory modes.
;        NOTE: THIS ROUTINE WILL CRASH ON AN APPLE //C due to writing to $C029,
;        so it is imperative that the caller ensures the machine type.
;        Thanks to John Brooks for explaining all of this to me. Twice.
; out:   text page clobbered (but screen holes preserved)
;        $2000..$9FFF/aux cleared
;------------------------------------------------------------------------------
BlankSHR
         jsr   Home

         lda   #%01000001             ; set GS NEWVIDEO mode to turn on linearize
         sta   NEWVIDEO

         sta   WRITEAUXMEM           ; writes go to auxmem

         ldx   #$00                  ; enable auxmem-to-bank-E1 shadowing on IIgs
         stx   SHADOW

; VIDHD-SPECIFIC HACK HERE!
; On the II/II+/IIe, all $C03x addresses are aliases for $C030, i.e. the speaker.
; Any single access of the speaker register requires a second access within a short
; time to balance the level if we want to avoid an audible click, which we do here.
; Since we can't read from SHADOW before writing to it (it returns random values on
; 8-bit machines, which VidHD interprets as invalid graphic modes and crashes hard),
; we instead balance the speaker access with a second write to the same speaker-
; aliased softswitch. Do not remove.
         stx   SHADOW

         lsr                         ; clear $2000..$9FFF in auxmem
         ldx   #$80
         jsr   ClearMem

         sta   WRITEMAINMEM          ; writes go to main memory

         lda   #%11000001            ; set GS NEWVIDEO mode to turn on SHR mode
         sta   NEWVIDEO

         rts