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Inching my way towards a full drawing routine

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Brendan Robert 2014-08-07 11:00:35 -05:00
parent 072a6c22c5
commit 9dbe9a9656
1 changed files with 57 additions and 5 deletions
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62
Platform/Apple/virtual/src/tile/tile.s
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@ -55,9 +55,11 @@ DRAW_X_START = $5E ; Starting column being drawn (between 0 and VIEWPORT_WIDTH)
DRAW_Y_START = $5F ; Starting row being drawn (between 0 and VIEWPORT_WIDTH)
SECTION_X_START = $60 ; X Offset relative to current section being drawn
SECTION_Y_START = $61 ; Y Offset relative to current section being drawn
DRAW_WIDTH = $62 ; Number of columns to draw for current section
DRAW_HEIGTH = $63 ; Number of rows to draw for current section
DRAW_WIDTH = $62 ; Number of columns to draw for current section (cannot be destroyed by drawing loop)
DRAW_HEIGTH = $63 ; Number of rows to draw for current section (cannot be destroyed by drawing loop)
DRAW_SECTION = $64 ; Location of section data being drawn
X_COUNTER = $65 ; Loop counter used during drawing
Y_COUNTER = $66 ; Loop counter used during drawing
; >> INIT (reset map drawing vars)
INIT
@ -390,10 +392,36 @@ DRAW
;
; The calculation goes like this: Page + $78 + (Row * $100) + (Col & 7) + ((Col & 8) << 4)
; When the display is drawn, the screen hole is compared to see if there is a different tile to draw
; and if there isn't then the tile is skipped. Otherwise the tile is drawn, etc.
; and if there is not then the tile is skipped. Otherwise the tile is drawn, etc.
;--------------------------------------
COL_OFFSET = 2
ROW_OFFSET = 3
; Identify start of map data (upper left)
;tblHGRl, tblHGRh lookups are 24-row based, successive lines inside there are at 0x0400 offsets
; Self-modifying code: Update all the STA statements in the drawTile section
LDA tblHGRl+ROW_OFFSET, Y
ADC #COL_OFFSET
!for store, 32 {
STA drawTile+(store*7)+4
!if store=16 {
LDA tblHGRl+ROW_OFFSET+1, Y
}
}
LDA tblHGRh+ROW_OFFSET, Y
!for store, 32 {
STA drawTile+(store*7)+5
!if store=15 {
LDA tblHGRh+ROW_OFFSET+1, Y
} else {
!if store < 31 {
adc #$04
}
}
}
; Display row of tiles
; Get tile
; Is there a NPC there?
@ -401,9 +429,33 @@ DRAW
; Yes, use NPC tile
; Compare tile to last-drawn tile
; Skip if no change
; Is this the first time we're drawing this row?
; Is this the first time we are drawing this row?
; -- It is, update the draw pointers
; If tile is different then redraw
; -- unrolled loop for 16 rows at a time
LDY #$00
drawTile !for row, 16 {
!for col, 2 {
LDA (TILE_SOURCE),Y
STA DRAW_ROW, X
INY
!if col = 0 {
INX
} else {
DEX
}
}
}
; Increment row
; Draw player
; Draw player
tblHGRl
!byte $00,$80,$00,$80,$00,$80,$00,$80
!byte $28,$A8,$28,$A8,$28,$A8,$28,$A8
!byte $50,$D0,$50,$D0,$50,$D0,$50,$D0
tblHGRh
!byte $00,$00,$01,$01,$02,$02,$03,$03
!byte $00,$00,$01,$01,$02,$02,$03,$03
!byte $00,$00,$01,$01,$02,$02,$03,$03