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Sprite state rework; have run out of bank space

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This commit is contained in:
Lucas Scharenbroich 2022-02-07 01:19:31 -06:00
parent 89ea425043
commit 397df074ac
6 changed files with 513 additions and 208 deletions
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7
src/Defs.s
View File

@ -81,7 +81,9 @@ BG1TileMapPtr equ 86
SCBArrayPtr equ 90 ; Used for palette binding
SpriteBanks equ 94 ; Bank bytes for the sprite data and sprite mask
LastRender equ 96 ; Record which reder function was last executed
Next equ 98
DamagedSprites equ 98
SpriteMap equ 100 ; Bitmap of open sprite slots.
Next equ 102
BankLoad equ 128
@ -114,6 +116,7 @@ DIRTY_BIT_BG1_X equ $0004
DIRTY_BIT_BG1_Y equ $0008
DIRTY_BIT_BG0_REFRESH equ $0010
DIRTY_BIT_BG1_REFRESH equ $0020
DIRTY_BIT_SPRITE_ARRAY equ $0040
; Script definition
YIELD equ $8000
@ -140,7 +143,7 @@ TILE_VFLIP_BIT equ $0400
TILE_HFLIP_BIT equ $0200
; Sprite constants
SPRITE_HIDE equ $8000
SPRITE_HIDE equ $2000
SPRITE_16X16 equ $1800
SPRITE_16X8 equ $1000
SPRITE_8X16 equ $0800

524
src/Sprite.s
View File

@ -5,13 +5,45 @@
; screen buffer. In order to be able to draw sprites offscreen, the virtual screen must be
; wider and taller than the physical graphics screen.
;
; Sprite State Machine
; NOTE: It may be posible to remove the sprite plane banks in the future and render directly from
; some small per-sprite graphic buffers. This would eliminate the need to erase/draw in
; the sprite planes and all drawing would go directly to the backing tiles. Need to
; figure out an efficient way to fall back when sprites are overlapping, though.
;
; EMPTY -> DIRTY <-> CLEAN
; ^ |
; | |
; +------ FREE <-----+
; All of the erasing must happen in an initial phase, because erasing a sprite could cause
; other sprites to be marked as "DAMAGED" which means they need to be drawn (similar to NEW state)
; What really has to happen in the various cases:
;
; When a sprite is added, it needs to
; * draw into the sprite buffer
; * add itself to the TS_SPRITE_FLAG bitfield on the tiles it occupies
; * mark the tiles it occupies as dirty
;
; When a sprite is updated (Tile ID or H/V flip flags), it needs to
; * erase itself from the sprite buffer
; * draw into the sprite buffer
; * mark the tiles it occupies as dirty
; * mark other sprites it intersects as DAMAGED
;
; When a sprite is moved, it needs to
; * erase itself from the sprite buffer at the old locations
; * remove itself from the TS_SPRITE_FLAG bitfields on the tiles it occupied
; * mark sprites that intersect as DAMAGED
; * draw into the sprite buffer at the new location
; * add itself to the TS_SPRITE_FLAG bitfield on the tiles it now occupies
; * mark the tiles it occupied as dirty
; * mark other sprites it intersects as DAMAGED
;
; When a sprite is removed, it needs to
; * erase itself from the sprite buffer at the old locations
; * remove itself from the TS_SPRITE_FLAG bitfields on the tiles it occupied
; * mark other sprites it intersects as DAMAGED
;
; The reason that things are broken into phases is that we have to handle all of the erasing first,
; set dirty tiles, identify DAMAGED sprites, and THEN perform the drawing. It is not possible to
; just do each sprite one at a time.
;
; Initialize the sprite plane data and mask banks (all data = $0000, all masks = $FFFF)
InitSprites
ldx #$FFFE
@ -53,6 +85,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x ; Clear the bit in the bit field. This seems wasteful, but
and _SpriteBitsNot,y ; there is no indexed form of TSB/TRB and caching the value in
tsb DamagedSprites ; Mark which other sprites are impacted by this one
sta TileStore+TS_SPRITE_FLAG,x ; a direct page location, only saves 1 or 2 cycles per and costs 10.
jsr _PushDirtyTileX
@ -61,6 +94,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jsr _PushDirtyTileX
@ -69,6 +103,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jsr _PushDirtyTileX
@ -77,6 +112,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jsr _PushDirtyTileX
@ -93,6 +129,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jsr _PushDirtyTileX
@ -101,6 +138,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jsr _PushDirtyTileX
@ -109,6 +147,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jsr _PushDirtyTileX
@ -117,6 +156,7 @@ _ClearSpriteFromTileStore
rts
lda TileStore+TS_SPRITE_FLAG,x
and _SpriteBitsNot,y
tsb DamagedSprites
sta TileStore+TS_SPRITE_FLAG,x
jmp _PushDirtyTileX
@ -140,80 +180,98 @@ _ClearSpriteFromTileStore
; In the second phase, the sprite is re-drawn into the sprite plane buffers and the appropriate
; Tile Store locations are marked as dirty. It is important to recognize that the sprites themselves
; can be marked dirty, and the underlying tiles in the tile store are independently marked dirty.
forceSpriteFlag ds 2
_RenderSprites
; First step is to look at the StartX and StartY values. If the offsets have changed from the
; last time that the frame was rendered, then we need to mark all of the sprites as dirty so that
; the tiles on which they were located at the previous frame will be refreshed
;
; OPTIMIZATION NOTE: Should check that the sprite actually changes position. If the screen scrolls
; by +X, but the sprite moves by -X (so it's relative position is unchanged), then
; it does NOT need to be marked as dirty.
phase1 dw :phase1_0
dw :phase1_1,:phase1_2,:phase1_3,:phase1_4
dw :phase1_5,:phase1_6,:phase1_7,:phase1_8
dw :phase1_9,:phase1_10,:phase1_11,:phase1_12
dw :phase1_13,:phase1_14,:phase1_15,:phase1_16
stz forceSpriteFlag
lda StartX
cmp OldStartX
beq :no_chng_x
lda #SPRITE_STATUS_DIRTY
sta forceSpriteFlag
:no_chng_x
lda StartY
cmp OldStartY
beq :no_chng_y
lda #SPRITE_STATUS_DIRTY
sta forceSpriteFlag
:no_chng_y
:phase1_16
ldy activeSpriteList+30
jsr _DoPhase1
:phase1_15
ldy activeSpriteList+28
jsr _DoPhase1
:phase1_14
ldy activeSpriteList+26
jsr _DoPhase1
:phase1_13
ldy activeSpriteList+24
jsr _DoPhase1
:phase1_12
ldy activeSpriteList+22
jsr _DoPhase1
:phase1_11
ldy activeSpriteList+20
jsr _DoPhase1
:phase1_10
ldy activeSpriteList+18
jsr _DoPhase1
:phase1_9
ldy activeSpriteList+16
jsr _DoPhase1
:phase1_8
ldy activeSpriteList+14
jsr _DoPhase1
:phase1_7
ldy activeSpriteList+12
jsr _DoPhase1
:phase1_6
ldy activeSpriteList+10
jsr _DoPhase1
:phase1_5
ldy activeSpriteList+8
jsr _DoPhase1
:phase1_4
ldy activeSpriteList+6
jsr _DoPhase1
:phase1_3
ldy activeSpriteList+4
jsr _DoPhase1
:phase1_2
ldy activeSpriteList+2
jsr _DoPhase1
:phase1_1
ldy activeSpriteList
jsr _DoPhase1
:phase1_0
jmp phase1_rtn
; Alter first phase. _OpenListHead is, essentially, a count of how many sprites. We can use that as an early-out
; test to stop scanning the SPRITE_STATUS values once all active sprites have been accounted for.
; lda _OpenListHead
; beq :exit1
; lsr
; sta tmp0
; If this sprite has been MOVED or REMOVED, then clear its bit from the TS_SPRITE_FLAG in
; all of the tile store locations that it occupied on the previous frame and add those
; tile store locations to the dirty tile list.
_DoPhase1
; lda _Sprites+SPRITE_STATUS
; beq :exit1
; ldy #0
; jsr _ClearSprite
; dec tmp0
; beq :exit1
; lda _Sprites+SPRITE_STATUS+2
; beq :exit1
; ldy #2
; jsr _ClearSprite
; dec tmp0
; beq :exit1
; ...
;:exit1
; First phase, erase all dirty sprites
ldy #0
:loop1 lda _Sprites+SPRITE_STATUS,y ; If the status is zero, that's the sentinel value
beq :phase2
bit #SPRITE_STATUS_DIRTY+SPRITE_STATUS_FREE
beq :next1
; Erase the sprite from the Sprite Plane buffers
jsr _EraseSpriteY
; Mark all of the tile store indices that this sprite was drawn at as dirty and clear
; it's bit flag in the TS_SPRITE_FLAG
jsr _ClearSpriteFromTileStore
; Check to see if this was a FREE sprite. If so, then it's index can be returned to the
; open list
lda _Sprites+SPRITE_STATUS,y
bit #SPRITE_STATUS_FREE
beq :next1
ora forceSpriteFlag
bit #SPRITE_STATUS_MOVED+SPRITE_STATUS_REMOVED
beq :no_clear
jsr _ClearSpriteFromTileStore
:no_clear
; If this sprite has been MOVED, UPDATED or REMOVED, then it needs to be erased from the
; sprite plane buffer
lda _Sprites+SPRITE_STATUS,y
bit #SPRITE_STATUS_MOVED+SPRITE_STATUS_UPDATED+SPRITE_STATUS_REMOVED
beq :no_erase
jsr _EraseSpriteY
:no_erase
; Check to see if sprite was REMOVED If so, then this is where we return its Sprite ID to the
; list of open slots
lda _Sprites+SPRITE_STATUS,y
bit #SPRITE_STATUS_REMOVED
beq :out
lda #SPRITE_STATUS_EMPTY ; Mark as empty
sta _Sprites+SPRITE_STATUS,y
lda _SpriteBits,y ; Clear from the sprite bitmap
trb SpriteMap
ldx _OpenListHead
dex
dex
@ -221,52 +279,178 @@ _RenderSprites
tya
sta _OpenList,x
sty _NextOpenSlot
:out
rts
:next1 iny
iny
cpy #2*MAX_SPRITES
bcc :loop1
:phase2
; Second phase takes care of drawing the sprites and marking the tiles that will need to be merged
; with pixel data from the sprite plane
phase2 dw :phase2_0
dw :phase2_1,:phase2_2,:phase2_3,:phase2_4
dw :phase2_5,:phase2_6,:phase2_7,:phase2_8
dw :phase2_9,:phase2_10,:phase2_11,:phase2_12
dw :phase2_13,:phase2_14,:phase2_15,:phase2_16
; Second step is to scan the list of sprites. A sprite is either clean or dirty. If it's dirty,
; then its position had changed, so we need to add tiles to the dirty queue to make sure the
; playfield gets updated. If it's clean, we can skip everything.
:phase2_16
ldy activeSpriteList+30
jsr _DoPhase2
:phase2_15
ldy activeSpriteList+28
jsr _DoPhase2
:phase2_14
ldy activeSpriteList+26
jsr _DoPhase2
:phase2_13
ldy activeSpriteList+24
jsr _DoPhase2
:phase2_12
ldy activeSpriteList+22
jsr _DoPhase2
:phase2_11
ldy activeSpriteList+20
jsr _DoPhase2
:phase2_10
ldy activeSpriteList+18
jsr _DoPhase2
:phase2_9
ldy activeSpriteList+16
jsr _DoPhase2
:phase2_8
ldy activeSpriteList+14
jsr _DoPhase2
:phase2_7
ldy activeSpriteList+12
jsr _DoPhase2
:phase2_6
ldy activeSpriteList+10
jsr _DoPhase2
:phase2_5
ldy activeSpriteList+8
jsr _DoPhase2
:phase2_4
ldy activeSpriteList+6
jsr _DoPhase2
:phase2_3
ldy activeSpriteList+4
jsr _DoPhase2
:phase2_2
ldy activeSpriteList+2
jsr _DoPhase2
:phase2_1
ldy activeSpriteList
jsr _DoPhase2
:phase2_0
jmp phase2_rtn
ldy #0
:loop lda _Sprites+SPRITE_STATUS,y ; If the status is zero, that's the sentinel value
beq :out
_DoPhase2
lda _Sprites+SPRITE_STATUS,y
ora forceSpriteFlag
and #SPRITE_STATUS_DIRTY ; If the dirty flag is set, do the things....
bne :render
:next
iny
iny
bra :loop
:out rts
and #SPRITE_STATUS_ADDED+SPRITE_STATUS_MOVED+SPRITE_STATUS_UPDATED
beq :out
; This is the complicated part; we need to draw the sprite into the sprite plane, but then
; calculate the tiles that overlap with the sprite potentially and mark those as dirty _AND_
; store the appropriate sprite plane address from which those tiles need to copy.
:render
sty tmp0 ; stash the Y register
; Draw the sprite into the sprite plane buffer(s)
lda _Sprites+SPRITE_ID,y
bit #SPRITE_HIDE
bne :next
jsr _DrawSpriteYA ; Use variant that takes the Y-register arg
;
; Mark the appropriate tiles as dirty and as occupied by a sprite so that the ApplyTiles
; subroutine will get the drawn data from the sprite plane into the code field where it
; can be drawn to the screen
ldx tmp0 ; Restore the index into the sprite array
jsr _MarkDirtySprite ; Mark the tiles that this sprite overlaps as dirty
jsr _MarkDirtySprite
ldy tmp0 ; Restore the index again
bra :next
; Draw the sprite into the sprite plane buffer(s)
lda _Sprites+SPRITE_DISP2,y ; use bits 9, 10, 11, 12, and 13 to dispatch
jmp (draw_sprite,x)
:out
rts
; Optimization: Could use 8-bit registers to save
RebuildSpriteArray
ldx #0 ; Number of non-empty sprite locations
lda SpriteMap ; Get the bit field
tay ; Cache to restore
bit #$0001 ; For each bit position, test and store a value
beq :chk1
stz activeSpriteList ; Shortcut for the first one
ldx #2
; A super-optimization here would be to put the activeSpriteList on the direct page (32 bytes) and then
; use PEA instructions to push the slot values. Calculate the count at the end based on the final stack
; address. Only 160 cycles to build the list.
:chk1
]flag equ $0002
]slot equ $0002
lup 15
bit #]flag
beq :chk2
lda #]slot
sta activeSpriteList,x
tya
inx
inx
:chk2
]flag equ ]flag*2
]slot equ ]slot+2
--^
stx activeSpriteCount
rts
forceSpriteFlag ds 2
_RenderSprites
stz DamagedSprites ; clear the potential set of damaged sprites
; Check to see if any sprites have been added or removed. If so, then we regenerate the active
; sprite list. Since adding and removing sprites is rare, this is a worthwhile tradeoff, because
; there are several places where we want to interative over the all of the sprites, and having a list
; and not have to contantly load and test the SPRITE_STATUS just to skip unused slots can help streamline
; the code.
lda #DIRTY_BIT_SPRITE_ARRAY
trb DirtyBits ; clears the flag, if it was set
beq :no_rebuild
jsr RebuildSpriteArray
:no_rebuild
; First step is to look at the StartX and StartY values. If the screen has scrolled, then it has
; the same effect as moving all of the sprites.
;
; OPTIMIZATION NOTE: Should check that the sprite actually changes position. If the screen scrolls
; by +X, but the sprite moves by -X (so it's relative position is unchanged), then
; it does NOT need to be marked as dirty.
stz forceSpriteFlag
lda StartX
cmp OldStartX
bne :force_update
lda StartY
cmp OldStartY
beq :no_change
:force_update
lda #SPRITE_STATUS_MOVED
sta forceSpriteFlag
:no_change
; Dispatch to the first phase of rendering the sprites. By pre-building the list, we know exactly
; how many sprite to process and they are in a contiguous array. So we on't have to keep track
; of an iterating variable
ldx activeSpriteCount
jmp (phase1,x)
phase1_rtn
; Dispatch to the second phase of rendering the sprites.
ldx activeSpriteCount
jmp (phase2,x)
phase2_rtn
; Speite rendering complete
rts
; _GetTileAt
;
@ -323,20 +507,21 @@ _EraseSpriteY
; X = _Sprites array offset
_DrawSprite
txy
_DrawSpriteY
lda _Sprites+SPRITE_ID,y
_DrawSpriteYA
and #$1E00 ; use bits 9, 10, 11 and 12 to dispatch
xba
tax
jmp (:draw_sprite,x)
:draw_sprite dw draw_8x8,draw_8x8h,draw_8x8v,draw_8x8hv
lda _Sprites+SPRITE_DISP2,y ; use bits 9, 10, 11 and 12,13 to dispatch
jmp (draw_sprite,x)
draw_sprite dw draw_8x8,draw_8x8h,draw_8x8v,draw_8x8hv
dw draw_8x16,draw_8x16h,draw_8x16v,draw_8x16hv
dw draw_16x8,draw_16x8h,draw_16x8v,draw_16x8hv
dw draw_16x16,draw_16x16h,draw_16x16v,draw_16x16hv
dw :rtn,:rtn,:rtn,:rtn ; hidden bit is set
dw :rtn,:rtn,:rtn,:rtn
dw :rtn,:rtn,:rtn,:rtn
dw :rtn,:rtn,:rtn,:rtn
:rtn rts
draw_8x8
draw_8x8h
ldx _Sprites+VBUFF_ADDR,y
@ -924,7 +1109,7 @@ _GetSpriteVBuffAddrTmp
; Add a new sprite to the rendering pipeline
;
; The tile id ithe range 0 - 511. The top 7 bits are used as sprite control bits
; The tile id in the range 0 - 511. The top 7 bits are used as sprite control bits
;
; Bit 9 : Horizontal flip.
; Bit 10 : Vertical flip.
@ -957,7 +1142,6 @@ AddSprite ENT
_AddSprite
phx ; Save the horizontal position
ldx _NextOpenSlot ; Get the next free sprite slot index
bpl :open ; A negative number means we are full
@ -965,13 +1149,13 @@ _AddSprite
sec ; Signal that no sprite slot was available
rts
:open
:open
sta _Sprites+SPRITE_ID,x ; Keep a copy of the full descriptor
jsr _GetTileAddr ; This applies the TILE_ID_MASK
sta _Sprites+TILE_DATA_OFFSET,x
lda #SPRITE_STATUS_DIRTY
sta _Sprites+SPRITE_STATUS,x ; Mark this sprite slot as occupied and that it needs to be drawn
lda #SPRITE_STATUS_OCCUPIED+SPRITE_STATUS_ADDED
sta _Sprites+SPRITE_STATUS,x
tya
sta _Sprites+SPRITE_Y,x ; Y coordinate
@ -983,6 +1167,15 @@ _AddSprite
jsr _PrecalcAllSpriteInfo ; Cache stuff
; Mark the dirty bit to indicate that the active sprite list needs to be rebuild in the next
; render call
lda #DIRTY_BIT_SPRITE_ARRAY
tsb DirtyBits
lda _SpriteBits,x ; Get the bit flag for this sprite slot
tsb SpriteMap ; Mark it in the sprite map bit field
txa ; And return the sprite ID
clc ; Mark that the sprite was successfully added
@ -1007,11 +1200,60 @@ _AddSprite
; X = sprite index
_PrecalcAllSpriteInfo
lda _Sprites+SPRITE_ID,x
and #$1800 ; use bits 11 and 12 to dispatch (oly care about size)
and #$2E00
xba
sta _Sprites+SPRITE_DISP2,x ; use bits 9 through 13 for full dispatch
lda _Sprites+SPRITE_ID,x
and #$1800 ; use bits 11 and 12 to dispatch (only care about size)
lsr
lsr
xba
sta _Sprites+SPRITE_DISP,x
; Clip the sprite's bounding box to the play field size and also set a flag if the sprite
; is fully offs-screen or not
tay ; use the index we just calculated
lda _Sprites+SPRITE_X,x
bpl :pos_x
lda #0
:pos_x cmp ScreenWidth
bcs :offscreen ; sprite is off-screen, exit early
sta _Sprites+SPRITE_CLIP_LEFT,x
lda _Sprites+SPRITE_Y,x
bpl :pos_y
lda #0
:pos_y cmp ScreenHeight
bcs :offscreen ; sprite is off-screen, exit early
sta _Sprites+SPRITE_CLIP_TOP,x
lda _Sprites+SPRITE_X,x
clc
adc _SpriteWidthMinus1,y
bmi :offscreen
cmp ScreenWidth
bcc :ok_x
lda ScreenWidth
dec
:ok_x sta _Sprites+SPRITE_CLIP_RIGHT,x
lda _Sprites+SPRITE_Y,x
clc
adc _SpriteHeightMinus1,y
bmi :offscreen
cmp ScreenHeight
bcc :ok_y
lda ScreenHeight
dec
:ok_y sta _Sprites+SPRITE_CLIP_BOTTOM,x
stz _Sprites+IS_OFF_SCREEN,x ; passed all of the off-screen test
rts
:offscreen
lda #1
sta _Sprites+IS_OFF_SCREEN,x
rts
; Remove a sprite from the list. Just mark its STATUS as FREE and it will be
@ -1030,8 +1272,9 @@ _RemoveSprite
tax
_RemoveSpriteX
lda #SPRITE_STATUS_FREE ; This will tell the renderer to erase the sprite,
sta _Sprites+SPRITE_STATUS,x ; but then remove it from the list
lda _Sprites+SPRITE_STATUS,x
ora #SPRITE_STATUS_REMOVED
sta _Sprites+SPRITE_STATUS,x
rts
; Update the sprite's flags. We do not allow the size of a sprite to be changed. That requires
@ -1065,7 +1308,8 @@ _UpdateSpriteXnc
jsr _PrecalcAllSpriteInfo ; Cache stuff
lda #SPRITE_STATUS_DIRTY ; Content is changing, mark as dirty
lda _Sprites+SPRITE_STATUS,x
ora #SPRITE_STATUS_UPDATED
sta _Sprites+SPRITE_STATUS,x
rts
@ -1108,8 +1352,9 @@ _MoveSpriteXnc
tya
sta _Sprites+OLD_VBUFF_ADDR,x
lda #SPRITE_STATUS_DIRTY ; Position is changing, mark as dirty
sta _Sprites+SPRITE_STATUS,x ; Mark this sprite slot as occupied and that it needs to be drawn
lda _Sprites+SPRITE_STATUS,x
ora #SPRITE_STATUS_MOVED
sta _Sprites+SPRITE_STATUS,x
rts
@ -1126,13 +1371,23 @@ _MoveSpriteXnc
NUM_BUFF_LINES equ 24
MAX_SPRITES equ 16
SPRITE_REC_SIZE equ 36
SPRITE_REC_SIZE equ 48
SPRITE_STATUS_EMPTY equ 0 ; slot is unitialized / free
SPRITE_STATUS_CLEAN equ 1 ;
SPRITE_STATUS_DIRTY equ 2
SPRITE_STATUS_FREE equ 4
SPRITE_STATUS_DAMAGED equ 8
; Mark each sprite as ADDED, UPDATED, MOVED, REMOVED depending on the actions applied to it
; on this frame. Quick note, the same Sprite ID cannot be removed and added in the same frame.
; A REMOVED sprite if removed from the sprite list during the Render call, so it's ID is not
; available to the AddSprite function until the next frame.
SPRITE_STATUS_EMPTY equ $0000 ; If the status value is zero, this sprite slot is available
SPRITE_STATUS_OCCUPIED equ $8000 ; Set the MSB to flag it as occupied
SPRITE_STATUS_ADDED equ $0001 ; Sprite was just added (new sprite)
SPRITE_STATUS_MOVED equ $0002 ; Sprite's position was changed
SPRITE_STATUS_UPDATED equ $0004 ; Sprite's non-position attributes were changed
SPRITE_STATUS_REMOVED equ $0008 ; Sprite has been removed.
; Each subroutine just sets the relevant bits, so it's possible to call AddSprite / UpdateSprite / MoveSprite
; and RemoveSprite in a single frame. These bits have priorities, so in this case, the sprite is immediately
; removed and never displayed.
SPRITE_STATUS equ {MAX_SPRITES*0}
TILE_DATA_OFFSET equ {MAX_SPRITES*2}
@ -1152,6 +1407,12 @@ TILE_STORE_ADDR_8 equ {MAX_SPRITES*28}
TILE_STORE_ADDR_9 equ {MAX_SPRITES*30}
TILE_STORE_ADDR_10 equ {MAX_SPRITES*32}
SPRITE_DISP equ {MAX_SPRITES*34} ; pre-calculated index for jmp (abs,x) based on sprite size
SPRITE_CLIP_LEFT equ {MAX_SPRITES*36}
SPRITE_CLIP_RIGHT equ {MAX_SPRITES*38}
SPRITE_CLIP_TOP equ {MAX_SPRITES*40}
SPRITE_CLIP_BOTTOM equ {MAX_SPRITES*42}
IS_OFF_SCREEN equ {MAX_SPRITES*44}
SPRITE_DISP2 equ {MAX_SPRITES*46}
; Maintain the index of the next open sprite slot. This allows us to have amortized
; constant sprite add performance. A negative value means no slots are available.
@ -1160,3 +1421,8 @@ _OpenListHead dw 0
_OpenList dw 0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,$FFFF ; List with sentinel at the end
_Sprites ds SPRITE_REC_SIZE*MAX_SPRITES
; On-demand cached list of active sprite slots
activeSpriteCount ds 2
activeSpriteList ds 2*MAX_SPRITES

127
src/Sprite2.s
View File

@ -1,19 +1,20 @@
; Scratch space to lay out idealized _MakeDirtySprite
; On input, X register = Sprite Array Index
Left equ tmp1
Right equ tmp2
Top equ tmp3
Bottom equ tmp4
;Left equ tmp1
;Right equ tmp2
;Top equ tmp3
;Bottom equ tmp4
TileTop equ tmp5
RowTop equ tmp6
AreaIndex equ tmp7
Origin equ tmp4
TileTop equ tmp5
RowTop equ tmp6
AreaIndex equ tmp7
TileLeft equ tmp8
ColLeft equ tmp9
TileLeft equ tmp8
ColLeft equ tmp9
SpriteBit equ tmp10 ; set the bit of the value that if the current sprite index
VBuffOrigin equ tmp11
SpriteBit equ tmp10 ; set the bit of the value that if the current sprite index
VBuffOrigin equ tmp11
; Helper function to take a local pixel coordinate [0, ScreenWidth-1],[0, ScreenHeight-1] and return the
; row and column in the tile store that is corresponds to. This takes into consideration the StartX and
@ -83,53 +84,13 @@ _LocalToTileStore
mdsOut rts
_MarkDirtySprite
stz _Sprites+TILE_STORE_ADDR_1,x ; Clear the this sprite's dirty tile list in case of an early exit
lda _SpriteBits,x ; Cache its bit flag to mark in the tile slots
lda #0
sta _Sprites+TILE_STORE_ADDR_1,y ; Clear this sprite's dirty tile list in case of an early exit
lda _SpriteBits,y ; Cache its bit flag to mark in the tile slots
sta SpriteBit
; Clip the sprite's extent to the screen so we can assume (mostly) position values from here on out. Note that
; the sprite width and height are _only_ used in the clip and afterward all calculation use the clip rect
;
; OPTIMIZATION NODE: These values can be calculated in AddSprite/MoveSprite once and stored in the sprite
; record since the screen size doesn't change. An off-screen flag can be set.
ldy _Sprites+SPRITE_DISP,x ; Get an index into the height/width tables based on the sprite bits
; lda _Sprites+IS_OFF_SCREEN,x ; Check if the sprite is visible in the playfield
; bne mdsOut
lda _Sprites+SPRITE_X,x
bpl :pos_x
lda #0
:pos_x cmp ScreenWidth
bcs mdsOut ; sprite is off-screen, exit early
sta Left
lda _Sprites+SPRITE_Y,x
bpl :pos_y
lda #0
:pos_y cmp ScreenHeight
bcs mdsOut ; sprite is off-screen, exit early
sta Top
lda _Sprites+SPRITE_X,x
clc
adc _SpriteWidthMinus1,y
bmi mdsOut ; another off-screen test
cmp ScreenWidth
bcc :ok_x
lda ScreenWidth
dec
:ok_x sta Right
lda _Sprites+SPRITE_Y,x
clc
adc _SpriteHeightMinus1,y
bmi mdsOut ; another off-screen test
cmp ScreenHeight
bcc :ok_y
lda ScreenHeight
dec
:ok_y sta Bottom
lda _Sprites+IS_OFF_SCREEN,y ; Check if the sprite is visible in the playfield
bne mdsOut
; At this point we know that we have to update the tiles that overlap the sprite plane rectangle defined
; by (Top, Left), (Bottom, Right). The general process is to figure out the top-left coordinate in the
@ -137,17 +98,17 @@ _MarkDirtySprite
; that need to be dirtied to cover the sprite.
clc
lda Top
lda _Sprites+SPRITE_CLIP_TOP,y
adc StartYMod208 ; Adjust for the scroll offset (could be a negative number!)
tay ; Save this value
tax ; Save this value
and #$0007 ; Get (StartY + SpriteY) mod 8
eor #$FFFF
inc
clc
adc Top ; subtract from the Y position (possible to go negative here)
adc _Sprites+SPRITE_CLIP_TOP,y ; subtract from the Y position (possible to go negative here)
sta TileTop ; This position will line up with the tile that the sprite overlaps with
tya ; Get back the position of the sprite top in the code field
txa ; Get back the position of the sprite top in the code field
cmp #208 ; check if we went too far positive
bcc *+5
sbc #208
@ -157,7 +118,7 @@ _MarkDirtySprite
and #$FFFE ; Store the pre-multiplied by 2 for indexing in the :mark_R_C routines
sta RowTop
lda Bottom ; Figure out how many tiles are needed to cover the sprite's area
lda _Sprites+SPRITE_CLIP_BOTTOM,y ; Figure out how many tiles are needed to cover the sprite's area
sec
sbc TileTop
and #$0018 ; Clear out the lower bits and stash in bits 4 and 5
@ -166,17 +127,17 @@ _MarkDirtySprite
; Repeat to get the same information for the columns
clc
lda Left
lda _Sprites+SPRITE_CLIP_LEFT,y
adc StartXMod164
tay
tax
and #$0003
eor #$FFFF
inc
clc
adc Left
adc _Sprites+SPRITE_CLIP_LEFT,y
sta TileLeft
tya
txa
cmp #164
bcc *+5
sbc #164
@ -185,7 +146,15 @@ _MarkDirtySprite
and #$FFFE ; Same pre-multiply by 2 for later
sta ColLeft
; Sneak a pre-calculation here. Calculate the upper-left corder of the sprite in the sprite plane.
; Calculate the offset into the TileStore lookup array for the top-left tile
; ldx RowTop
; lda ColLeft
; clc
; adc TileStore2DYTable,x ; Fixed offset to the next row
; sta Origin ; This is the index into the TileStore2DLookup table
; Sneak a pre-calculation here. Calculate the tile-aligned upper-left corner of the sprite in the sprite plane.
; We can reuse this in all of the routines below. This is not the (x,y) of the sprite itself, but
; the corner of the tile it overlaps with
@ -199,9 +168,7 @@ _MarkDirtySprite
; Calculate the number of columns and dispatch
txy ; Swap the sprite index into the Y register
lda Right
lda _Sprites+SPRITE_CLIP_RIGHT,y
sec
sbc TileLeft
and #$000C
@ -352,18 +319,32 @@ _MarkDirtySprite
rts
; Begin List of subroutines to mark each tile offset
;
; If we had a double-sized 2D array to be able to look up the tile store address without
; adding rows and column, we could save ~6 cycles per tile
:mark_0_0
ldx RowTop
lda ColLeft
clc
adc TileStoreYTable,x ; Fixed offset to the next row
tax ; This is the tile store offset
tax
lda VBuffOrigin
; adc #{0*4}+{0*256}
sta TileStore+TS_SPRITE_ADDR,x
; ldx Origin
; lda TileStore2DLookup,x
; tax ; This is the tile store offset
lda VBuffOrigin ; This is an interesting case. The mapping between the tile store
; adc #{0*4}+{0*256} ; and the sprite buffers changes as the StartX, StartY values change
sta TileStore+TS_SPRITE_ADDR,x ; but don't depend on any sprite information. However, by setting the
; value only for the tiles that get added to the dirty tile list, we
; can avoid recalculating over 1,000 values whenever the screen scrolls
; (which is common) and just limit it to the number of tiles covered by
; the sprites. If the screen is not scrolling and the sprites are not
; moving and they are being dirtied, then we may do more work, but the
; odds are in our favor to just take care of it here.
lda TileStore+TS_SPRITE_FLAG,x
lda SpriteBit
ora TileStore+TS_SPRITE_FLAG,x
sta TileStore+TS_SPRITE_FLAG,x

17
src/blitter/Tables.s
View File

@ -238,6 +238,18 @@ TileStoreYTable ENT
]step = ]step+{41*2}
--^
;TileStore2DYTable
;]step equ 0
; lup 26
; dw ]step
;]step = ]step+{41*2*2}
; --^
;]step equ 0
; lup 26
; dw ]step
;]step = ]step+{41*2*2}
; --^
; Create a table to look up the "next" column with modulo wraparound. Basically a[i] = i
; and the table is double-length. Use constant offsets to pick an amount to advance
NextCol
@ -252,6 +264,11 @@ NextCol
]step = ]step+2
--^
; A double-sized table of lookup values. This is basically the cross-product of TileStoreYTable and
; NextCol. If is double-width and double-height so that, if we know a tile's address position
; of (X + 41*Y), then any relative tile store address can be looked up by adding a constan value.
;TileStore2DLookup ds {26*41*2}*4
; This is a double-length table that holds the right-edge adresses of the playfield on the physical
; screen. At most, it needs to hold 200 addresses for a full height playfield. It is double-length
; so that code can pick any offset and copy values without needing to check for a wrap-around. If the

4
src/blitter/Template.s
View File

@ -201,8 +201,8 @@ Counter equ tmp3
:tsloop
lda (NextColPtr),y ; Need to recalculate each time since the wrap-around could
clc ; happen anywhere
adc (RowAddrPtr)
tax
adc (RowAddrPtr) ;
tax ; NOTE: Try to rework to use new TileStore2DLookup array
lda OnScreenAddr
sta TileStore+TS_SCREEN_ADDR,X

42
src/blitter/Tiles.s
View File

@ -533,6 +533,36 @@ InitTiles
cpy #26*2
bcc :yloop
; Fill in the TileStore2DLookup array. This is a full array lookup for the entire tile store space. Eventually
; we can remove TileStoreYTable and free up a bit of space.
lda #0
tay
tax
:xyloop
sta TileStoreYTable,y
sta TileStoreYTable+{2*41},y
sta TileStoreYTable+{4*41*26},y
sta TileStoreYTable+{4*41*26}+{2*41},y
inc ; Advance to the next offset value
inc
iny ; Advance to the next table location
iny
inx ; Increment the column counter
cpx #41 ; If we haven't filled an entire row, keep going
bcc :xyloop
ldx #0 ; reset the column counter
tya
clc
adc #2*26 ; skip over the repeated values in this row and to to the next row start
tay
cpy #4*41*26 ; Did we finish the last row, if not go back for more
bcc :xyloop
; Next, initialize the Tile Store itself
ldx #TILE_STORE_SIZE-2
@ -682,12 +712,20 @@ _PushDirtyTileX
sta TileStore+TS_DIRTY,x ; and is 1 cycle fater than loading a constanct value
; txa
ldx DirtyTileCount
sta DirtyTiles,x
ldx DirtyTileCount ; 5
sta DirtyTiles,x ; 5
inx
inx
stx DirtyTileCount
; Same speed, but preserved the Z register
; sta (DirtyTiles) ; 6
; lda DirtyTiles ; 4
; inc ; 2
; inc ; 2
; sta DirtyTiles ; 4
rts
:occupied2
txa ; Make sure TileStore offset is returned in the accumulator