Have successfully written a background tile to screen!
This commit is contained in:
greg 2016-12-07 01:13:29 -08:00
parent 2c6631c87e
commit da806439a5
3 changed files with 68 additions and 11 deletions

View File

@ -21,6 +21,11 @@ lvl3\@:
bne lvl3\@ bne lvl3\@
.ENDM .ENDM
.MACRO Set_A_8_XY_16
; 16-bit xy, 8-bit a
rep #%00010000
sep #%00100000
.ENDM
.MACRO Reset_Palette_Offset .MACRO Reset_Palette_Offset
stz $2121 stz $2121
@ -37,6 +42,6 @@ sta $2122
.MACRO Set_Screen_Brightness .MACRO Set_Screen_Brightness
lda #\1 lda #\1
sta $2100 sta $2100 ; $2100 is the screen brightness register
.ENDM .ENDM

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@ -4,10 +4,10 @@ $2100 - screen on/off + brightness
$2105 - screen format register, changes size of tiles $2105 - screen format register, changes size of tiles
$2107 - set starting tilemap location
$2121 - stores the index into CGRAM to write a color value via $2122 $2121 - stores the index into CGRAM to write a color value via $2122
$2122 - write a 2-byte SNES color value to the CGRAM. this auto-increments after writing, $2122 - write a 2-byte SNES color value to the CGRAM. this auto-increments after writing,
which is why $2121 needs to be written to reset this. it's common to write `stz $2121` which is why $2121 needs to be written to reset this. it's common to write `stz $2121`

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@ -15,26 +15,74 @@ VBlank:
.ORG 0 .ORG 0
.section "Main" .section "Main"
.MACRO Video_Port_Control
;VRAM transfer, word-access, increment by 1
lda #%10000000
sta $2115
.ENDM
;assumes 8-bit a, 16-bit xy
.MACRO Load_Block_to_VRAM ARGS SOURCE DEST SIZE
Video_Port_Control
ldx #DEST
stx $2116 ; $2116/2117 is 2byte address for VRAM upload/download. most significant bit must be 0
lda #:SOURCE ; source bank
ldx #SOURCE ; source offset
ldy #SIZE
stx $4302 ; store data offset into DMA control register
sta $4304 ; store bank into DMA source bank
sty $4305 ; store size of block
lda #$01
sta $4300 ; set DMA mode (word, normal increment)
lda #$18
sta $4301 ; set destination register (VRAM write register) - add value to $2100 to get destination address
; i.e. this is writing to $2118, which when written writes a byte to VRAM
lda #$01
sta $420b ; and start the transfer
.ENDM
Start: Start:
Snes_Init Snes_Init
; 16-bit xy, 8-bit a Set_A_8_XY_16
rep #%00010000
sep #%00100000
; Load palette by writing to $2122
; .db $00, $00, $E0, $7F, $1F, $00, $FF, $03
Load_Palette_Color $00, $00 Load_Palette_Color $00, $00
Load_Palette_Color $00, $00 Load_Palette_Color $00, $00
Load_Palette_Color $00, $00 Load_Palette_Color $00, $00
Load_Palette_Color $ff, $0a Load_Palette_Color $ff, $0a
;lda #%00000
Set_Screen_Brightness %00001111 Set_Screen_Brightness %00001111
lda #%00000000 ; 8x8 for all 4 backgrounds, no priority flip, Mode: 4 colors/tile w/ 32 palettes
sta $2105 ; store to screen mode register
; size (last argument) depends on color mode
; location is beginning of VRAM
Load_Block_to_VRAM Face, $0000, (8*2*2),
; put character data at VRAM $0000, tile data at $0400
lda #$04
sta $2107 ; BG1 tile map location (upper 6 bits)
lda #$00
sta $210b ; BG1 character location ($1000 word intervals - can't go over $8000 b/c size of VRAM)
; main screen designation
lda #%00000001
sta $212c ; enable bkg 1,
ldx #$0400 ; load $0400 (VRAM address of tile data)
stx $2116 ; and store it to VRAM address word-sized register
ldx #$0001
stx $2118 ;store tile map entry to the address specified in $2116 - this eincrements or not based on 2105
lda #%10000001 ; enable NMI and joypads lda #%10000001 ; enable NMI and joypads
sta $4200 sta $4200
@ -65,6 +113,10 @@ mainloop:
.section "TileData" .section "TileData"
Face: Face:
.db $00, $00, $00, $00, $00, $00, $00, $00
.db $00, $00, $00, $00, $00, $00, $00, $00
.db %00000000 .db %00000000
.db %00000000 .db %00000000