Apple-2gs-SW/iigs-game-engine
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First pass at validating erasing the sprite on update

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This commit is contained in:
Lucas Scharenbroich 2021-10-28 22:19:18 -05:00
parent 0a7d9e15c7
commit 9ecc262c58
3 changed files with 45 additions and 14 deletions
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56
demos/sprites/App.Main.s
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@ -47,6 +47,7 @@ DOWN_ARROW equ $0A
; Add a player sprite
stz PlayerX
stz PlayerXOld
lda #4
sta PlayerY
@ -58,42 +59,64 @@ DOWN_ARROW equ $0A
; leave it alone. We are just testing the ability to merge sprite plane data into
; the play field tiles.
EvtLoop
ldx PlayerX
ldy PlayerY
jsl GetSpriteVBuffAddr
tax ; put in X
ldy #3*128 ; draw the 3rd tile as a sprite
stx PlayerLastPos ; save for erasure
jsl DrawTileSprite
; Now the sprite has been drawn. Manually update the 4 top-left tiles. Since we have not scrolled
; the screen, these are the tiles in rows 0 and 1 and columns 0 and 1. The next step is to mark
; those tiles as intersecting a sprite
ldx #0
ldy #0
lda PlayerX
lsr
lsr
tax
ldy #0 ; Y is fixed
jsr MakeDirtyTile
ldx #1
ldy #0
jsr MakeDirtyTile
ldx #0
ldy #1
jsr MakeDirtyTile
ldx #1
; If we are not aligned in the x-direction, dirty the tile in front
lda PlayerX
bit #$0003
beq :skip1
inx
ldy #0
jsr MakeDirtyTile
ldy #1
jsr MakeDirtyTile
:skip1
; If we transitioned to an aligned status, then mark the prior tile as dirty
lda PlayerX
bit #$0003
bne :skip2
lda PlayerXOld
lsr
lsr
tax
ldy #0
jsr MakeDirtyTile
ldy #1
jsr MakeDirtyTile
:skip2
; Let's see what it looks like!
jsl Render
lda PlayerX ; Move the player sprite a bit
sta PlayerXOld
inc
and #$001F
sta PlayerX
ldx PlayerLastPos ; Delete the sprite because it moved
jsl EraseTileSprite
; tax
; ldy PlayerY
; lda PlayerID
@ -133,7 +156,9 @@ MyPalette dw $0000,$0777,$0F31,$0E51,$00A0,$02E3,$0BF1,$0FA4,$
PlayerID ds 2
PlayerX ds 2
PlayerXOld ds 2
PlayerY ds 2
PlayerLastPos ds 2
; x = column
; y = row
@ -152,11 +177,13 @@ MakeDirtyTile
tay
jsl GetSpriteVBuffAddr
ply
plx
pha
lda 3,s
tay
lda 5,s
tax
jsl GetTileStoreOffset
tax
lda #TILE_SPRITE_BIT
@ -165,6 +192,9 @@ MakeDirtyTile
stal TileStore+TS_SPRITE_ADDR,x
txy
jsl RenderTile
ply
plx
rts
; Position the screen with the botom-left corner of the tilemap visible

2
src/Core.s
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@ -46,8 +46,8 @@ EngineStartUp ENT
jsr EngineReset ; All of the resources are allocated, put the engine in a known state
jsr InitGraphics ; Initialize all of the graphics-related data
jsr InitSprites ; Initialize the sprite subsystem
nop
jsr InitSprites ; Initialize the sprite subsystem
jsr InitTiles ; Initialize the tile subsystem
jsr InitTimers ; Initialize the timer subsystem

1
src/GTE.s
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@ -51,6 +51,7 @@ GetTileStoreOffset EXT ; X = column, Y = row
TileStore EXT ; Tile store internal data structure
DrawTileSprite EXT ; X = target address in sprite plane, Y = address in tile bank
EraseTileSprite EXT ; X = target address is sprite plane
GetSpriteVBuffAddr EXT ; X = x-coordinate (0 - 159), Y = y-coordinate (0 - 199). Return in Acc.
; Allocate a full 64K bank