sprite_sheet.asm

.include "x16.inc"

.org $080D
.segment "STARTUP"
.segment "INIT"
.segment "ONCE"
.segment "CODE"
   jmp start

.include "filenames.asm"
spritesheet_fn: .asciiz "spritesheet.bin"
.include "loadvram.asm"
.include "globals.asm"

hscroll: .word 0
vscroll: .word 0
select_down: .byte 0
next_scale: .byte 128


start:
   ; Disable layers and sprites
   lda VERA_dc_video
   and #$8F
   sta VERA_dc_video

   ; Setup tiles on layer 1
   lda #$02                      ; 32x32 map of 4bpp tiles
   sta VERA_L1_config
   lda #((VRAM_TILEMAP >> 9) & $FF)
   sta VERA_L1_mapbase
   lda #((((VRAM_TILES >> 11) & $3F) << 2) | $03)  ; 16x16 tiles
   sta VERA_L1_tilebase
   stz VERA_L1_hscroll_l         ; set scroll position to 0,0
   stz VERA_L1_hscroll_h
   stz VERA_L1_vscroll_l
   stz VERA_L1_vscroll_h

   ; set display to 2x scale
   lda #64
   sta VERA_dc_hscale
   sta VERA_dc_vscale

   ; load VRAM data from binaries
   lda #>(VRAM_TILEMAP>>4)
   ldx #<(VRAM_TILEMAP>>4)
   ldy #<spritesheet_fn
   jsr loadvram

   lda #>(VRAM_TILES>>4)
   ldx #<(VRAM_TILES>>4)
   ldy #<sprites_fn
   jsr loadvram

   lda #>(VRAM_palette>>4)
   ldx #<(VRAM_palette>>4)
   ldy #<palette_fn
   jsr loadvram

   ; enable layer 1
   lda VERA_dc_video
   ora #$20
   sta VERA_dc_video

mainloop:
   wai
   bra mainloop