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Closer to having a workable first draft of tile rendering but not done yet

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Brendan Robert 2014-08-08 01:24:55 -05:00
parent 9dbe9a9656
commit 8f49e482c5
1 changed files with 96 additions and 21 deletions
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117
Platform/Apple/virtual/src/tile/tile.s
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@ -58,8 +58,9 @@ SECTION_Y_START = $61 ; Y Offset relative to current section being drawn
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
X_COUNTER = $66 ; Loop counter used during drawing
Y_COUNTER = $67 ; Loop counter used during drawing
ROW_LOCATION = $68 ; Used for pointing at row offset in map data
; >> INIT (reset map drawing vars)
INIT
@ -328,7 +329,7 @@ CROSS_WEST
SBC SECTION_Y_START
STA DRAW_HEIGHT
!move_word ptr, DRAW_SECTION
jsr mainDraw
jsr mainDraw
}
DRAW
@ -399,31 +400,94 @@ 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
LDY DRAW_Y_START
LDA tblHGRl+ROW_OFFSET, Y
ADC #COL_OFFSET
!for store, 32 {
STA drawTile+(store*7)+4
TAX
INX
!for store, 16 {
STA .drawTile+(store*14)+3
STX .drawTile+(store*14)+10
!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 {
!for store, 16 {
STA .drawTile+(store*14)+4
STA .drawTile+(store*14)+11
!if store = 7 {
LDA tblHGRh+ROW_OFFSET+1, Y
} else {
!if store < 31 {
; We have to calculate the start of the next row but only if we are not already at the last row
!if store < 15 {
adc #$04
}
}
}
;Calculate data offset == DRAW_SECTION + (row * 22) + 6 == DRAW_SECTION + (row * 2 + row * 4 + row * 16) + 6
CLC
LDA SECTION_Y_START ;row * 2
ASL
ADC #HEADER_LENGTH
ADC SECTION_X_START
STA ROW_LOCATION
LDA SECTION_Y_START ; row * 4
ASL
ASL
ADC ROW_LOCATION
STA ROW_LOCATION
LDA SECTION_Y_START ; row * 16 -- possibly carry
ASL
ASL
ASL
ASL
ADC ROW_LOCATION
STA ROW_LOCATION
LDA DRAW_SECTION + 1
ADC #$00 ; This is a short way for handling carry without a branch
STA ROW_LOCATION + 1
LDA DRAW_SECTION
ADC ROW_LOCATION
STA ROW_LOCATION
; Handle carry if needed
BCC .doneCalculatingLocation
INC ROW_LOCATION + 1
.doneCalculatingLocation
CLC
LDA SECTION_Y_START
ASL
ADC ROW_LOCATION
STA ROW_LOCATION
LDA SECTION_Y_START
ASL
ASL
ADC ROW_LOCATION
STA ROW_LOCATION
LDX DRAW_X_START
; Display row of tiles
.next_col
; Get tile
LDA ROW_LOCATION, X
; Calculate location of tile data == tile_base + ((tile & 31) * 16)
AND #31
ASL
ASL
ASL
ASL
STA TILE_SOURCE
LDA TILE_BASE
ADC #$00
STA TILE_SOURCE+1
LDA TILE_BASE
ADC TILE_SOURCE
STA TILE_SOURCE
BCC .doenCalculatingTileLocation
INC TILE_SOURCE+1
.doenCalculatingTileLocation
; Is there a NPC there?
; No, use map tile
; Yes, use NPC tile
@ -434,20 +498,31 @@ ROW_OFFSET = 3
; 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
TXA ; In the drawing part, we need X=X*2
ASL
TAX
.drawTile !for row, 16 {
.0 LDA (TILE_SOURCE),Y
.2 STA DRAW_ROW, X
.5 INY
.6 INX
.7 LDA (TILE_SOURCE),Y
.9 STA DRAW_ROW, X
!if row < 15 {
.12 INY
.13 DEX
}
}
}
DEC X_COUNTER
BMI .next_row
TXA ; Outside the drawing part we need to put X back (divide by 2)
LSR
TAX
BNE .next_col
; Increment row
.next_row
; Draw player
tblHGRl