iigs-game-engine/src/Render.s

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; Renders a frame of animation
;
; The render function is the point of committment -- most of the APIs that set sprites and
; update coordinates are lazy; they simply save their values and set a dirty flag in the
; DirtyBits word.
;
; This function examines the dirty bits and actually performs the work to update the code field
; and internal data structure to properly render the play field. Then the update pipeline is
; executed.
;
; Everything is composited into the tiles in the playfield and then the screen is rendered in
; a single pass.
Render ENT
phb
phk
plb
jsr _Render
plb
rtl
; TODO -- actually check the dirty bits and be selective on what gets updated. For example, if
; only the Y position changes, then we should only need to set new values on the
; virtual lines that were brought on screen. If the X position only changes by one
; byte, then we may have to change the CODE_ENTRY values or restore/set new OPCODE
; values, but not both.
; It's important to do _ApplyBG0YPos first because it calculates the value of StartY % 208 which is
; used in all of the other loops
_Render
jsr _ApplyBG0YPos ; Set stack addresses for the virtual lines to the physical screen
jsr _ApplyBG1YPos
; _ApplyBG0Xpos need to be split because we have to set the offsets, then draw in any updated tiles, and
; finally patch out the code field. Right now, the BRA operand is getting overwritten by tile data.
jsr _ApplyBG0XPosPre
jsr _ApplyBG1XPosPre
nop
jsr _RenderSprites ; Once the BG0 X and Y positions are committed, update sprite data
jsr _UpdateBG0TileMap ; and the tile maps. These subroutines build up a list of tiles
jsr _UpdateBG1TileMap ; that need to be updated in the code field
nop
jsr _ApplyTiles ; This function actually draws the new tiles into the code field
jsr _ApplyBG0XPos ; Patch the code field instructions with exit BRA opcode
jsr _ApplyBG1XPos ; Update the direct page value based on the horizontal position
; The code fields are locked in now and ready to be rendered
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; jsr _ShadowOff
; Shadowing is turned off. Render all of the scan lines that need a second pass. One
; optimization that can be done here is that the lines can be rendered in any order
; since it is not shown on-screen yet.
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; ldx #0 ; Blit the full virtual buffer to the screen
; ldy #8
; jsr _BltRange
; Turn shadowing back on
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; jsr _ShadowOn
; Now render all of the remaining lines in top-to-bottom (or bottom-to-top) order
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; lda ScreenY0 ; pass the address of the first line of the overlay
; clc
; adc #0
; asl
; tax
; lda ScreenAddr,x
; clc
; adc ScreenX0
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; jsl Overlay
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ldx #0 ; Blit the full virtual buffer to the screen
ldy ScreenHeight
jsr _BltRange
; ldx #0
; ldy ScreenHeight
; jsr _BltSCB
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lda StartY ; Restore the fields back to their original state
ldx ScreenHeight
jsr _RestoreBG0Opcodes
lda StartY
sta OldStartY
lda StartX
sta OldStartX
lda BG1StartY
sta OldBG1StartY
lda BG1StartX
sta OldBG1StartX
stz DirtyBits
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stz LastRender ; Mark that a full render was just performed
rts
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; This is a specialized render function that only updates the dirty tiles *and* draws them
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; directly onto the SHR graphics buffer. The playfield is not used at all. In some way, this
; ignores almost all of the capabilities of GTE, but it does provide a convenient way to use
; the sprite subsystem + tile attributes for single-screen games which should be able to run
; close to 60 fps.
;
; Because we are register starved, there is a lot of inline code to quickly fetch the information
; needed to render sprites appropriately. If there was a way to efficiently maintain an ordered
; and compact array of per-tile VBUFF addresses, rather than the current sparse array, then
; the sprite handling code could be significantly streamlined. A note for anyone attempting
; this optimization:
;
; The _MarkDirtyTiles simply stores a sprite's per-tile VBUFF address and marks the tile
; as being occupied by the sprite with just 4 instructions
;
; sta (vbuff_array_ptr),y
; lda TileStore+TS_SPRITE_FLAG,x
; ora SpriteBit,y
; sta TileStore+TS_SPRITE_FLAG,x
;
; Then, we have an unrolled loop that does repeated tests of
;
; lsr
; bcc *+
; lda vbuff_array_ptr,y
; sta spriteVBuffArr
;
; The only gain to be had is if the sprites that are marked are in the high bits and there are no low-index
; sprites. Skipping over N bits of the SPRITE_FLAG takes only 5*N cycles. So, on average, we might waste
; 40 cycles looking for the proper bit.
;
; Any improvement to the existing code would need to be able to maintain a data structure and get the final
; values into the spriteVBuffArr for a total cost of under 75 cycles per tile.
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RenderDirty ENT
phb
phk
plb
jsr _RenderDirty
plb
rtl
; In this renderer, we assume that there is no scrolling, so no need to update any information about
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; the BG0/BG1 positions
_RenderDirty
lda LastRender ; If the full renderer was last called, we assume that
bne :norecalc ; the scroll positions have likely changed, so recalculate
lda #2 ; blue
jsr _SetBorderColor
jsr _RecalcTileScreenAddrs ; them to make sure sprites draw at the correct screen address
:norecalc
lda #3 ; purple
jsr _SetBorderColor
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jsr _RenderSprites
lda #4 ; dk. green
jsr _SetBorderColor
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jsr _ApplyDirtyTiles
lda #1
sta LastRender
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rts
_ApplyDirtyTiles
bra :begin
:loop
; Retrieve the offset of the next dirty Tile Store items in the Y-register
jsr _PopDirtyTile2
; Call the generic dispatch with the Tile Store record pointer at by the Y-register.
phb
jsr _RenderDirtyTile
plb
; Loop again until the list of dirty tiles is empty
:begin ldy DirtyTileCount
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bne :loop
rts
; Only render solid tiles and sprites
_RenderDirtyTile
ldal TileStore+TS_SPRITE_FLAG,x ; This is a bitfield of all the sprites that intersect this tile, only care if non-zero or not
bne dirty_sprite
; The rest of this function handles that non-sprite blit, which is super fast since it blits directly from the
; tile data store to the graphics screen with no masking. The only extra work is selecting a blit function
; based on the tile flip flags.
pei TileStoreBankAndBank01 ; Special value that has the TileStore bank in LSB and $01 in MSB
plb
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lda TileStore+TS_DIRTY_TILE_DISP,x ; load and patch in the appropriate subroutine
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stal :tiledisp+1
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ldy TileStore+TS_SCREEN_ADDR,x ; Get the on-screen address of this tile
lda TileStore+TS_TILE_ADDR,y ; load the address of this tile's data (pre-calculated)
tax
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plb ; set the bank
; B is set to Bank 01
; A is set to the tile word offset (0 through 80 in steps of 4)
; Y is set to the top-left address of the tile in SHR screen
; X is set to the address of the tile data
:tiledisp jmp $0000 ; render the tile
; Use some temporary space for the spriteIdx array (maximum of 4 entries)
stkSave equ tmp9
screenAddr equ tmp10
tileAddr equ tmp11
spriteIdx equ tmp12
; Handler for the sprite path
dirty_sprite
pei TileStoreBankAndTileDataBank ; Special value that has the TileStore bank in LSB and TileData bank in MSB
plb
; Cache a couple of values into the direct page, but preserve the Accumulator
ldy TileStore+TS_TILE_ADDR,x ; load the address of this tile's data (pre-calculated)
sty tileAddr
ldy TileStore+TS_SCREEN_ADDR,x ; Get the on-screen address of this tile
sty screenAddr
; Now do all of the deferred work of actually drawing the sprites. We put considerable effort into
; figuring out if there is only one sprite or more than one since we optimize the former case as it
; is very common and can be done significantly faster.
;
; This is a big, unrolled chunk of code that packs the VBUFF addresses for the sprite positions marked
; in the bitfield into the spriteIdx array and then jumps to an optimized rendering function based on
; the number of sprites on the tile.
;
; After each set bit is identified, we check to see if that was the last one and immediately exit. Since
; a maximum of 4 sprites are processed per tile, this only results in (at most) 4 extra branch instructions.
ldy TileStore+TS_VBUFF_ARRAY_ADDR,x ; base address of the VBUFF sprite address array for this tile
lsr
bcc :loop_0_bit_1
ldx: $0000,y
stx spriteIdx
cmp #0
jne :loop_1_bit_1
jmp BlitOneSprite
:loop_0_bit_1 lsr
bcc :loop_0_bit_2
ldx: $0002,y
stx spriteIdx
cmp #0
jne :loop_1_bit_2
jmp BlitOneSprite
:loop_0_bit_2 lsr
bcc :loop_0_bit_3
ldx: $0004,y
stx spriteIdx
cmp #0
jne :loop_1_bit_3
jmp BlitOneSprite
:loop_0_bit_3 lsr
bcc :loop_0_bit_4
ldx: $0006,y
stx spriteIdx
cmp #0
jne :loop_1_bit_4
jmp BlitOneSprite
:loop_0_bit_4 lsr
bcc :loop_0_bit_5
ldx: $0008,y
stx spriteIdx
cmp #0
jne :loop_1_bit_5
jmp BlitOneSprite
:loop_0_bit_5 lsr
bcc :loop_0_bit_6
ldx: $000A,y
stx spriteIdx
cmp #0
jne :loop_1_bit_6
jmp BlitOneSprite
:loop_0_bit_6 lsr
bcc :loop_0_bit_7
ldx: $000C,y
stx spriteIdx
cmp #0
jne :loop_1_bit_7
jmp BlitOneSprite
:loop_0_bit_7 lsr
bcc :loop_0_bit_8
ldx: $000E,y
stx spriteIdx
cmp #0
jne :loop_1_bit_8
jmp BlitOneSprite
:loop_0_bit_8 lsr
bcc :loop_0_bit_9
ldx: $0010,y
stx spriteIdx
cmp #0
jne :loop_1_bit_9
jmp BlitOneSprite
:loop_0_bit_9 lsr
bcc :loop_0_bit_10
ldx: $0012,y
stx spriteIdx
cmp #0
jne :loop_1_bit_10
jmp BlitOneSprite
:loop_0_bit_10 lsr
bcc :loop_0_bit_11
ldx: $0014,y
stx spriteIdx
cmp #0
jne :loop_1_bit_11
jmp BlitOneSprite
:loop_0_bit_11 lsr
bcc :loop_0_bit_12
ldx: $0016,y
stx spriteIdx
cmp #0
jne :loop_1_bit_12
jmp BlitOneSprite
:loop_0_bit_12 lsr
bcc :loop_0_bit_13
ldx: $0018,y
stx spriteIdx
cmp #0
jne :loop_1_bit_13
jmp BlitOneSprite
:loop_0_bit_13 lsr
bcc :loop_0_bit_14
ldx: $001A,y
stx spriteIdx
cmp #0
jne :loop_1_bit_14
jmp BlitOneSprite
:loop_0_bit_14 lsr
bcc :loop_0_bit_15
ldx: $001C,y
stx spriteIdx
cmp #0
jne :loop_1_bit_15
jmp BlitOneSprite
; If we get to bit 15, then it *must* be a bit that is set
:loop_0_bit_15 ldx: $001E,y
stx spriteIdx
jmp BlitOneSprite
:loop_1_bit_1 lsr
bcc :loop_1_bit_2
ldx: $0002,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_2
jmp BlitTwoSprites
:loop_1_bit_2 lsr
bcc :loop_1_bit_3
ldx: $0004,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_3
jmp BlitTwoSprites
:loop_1_bit_3 lsr
bcc :loop_1_bit_4
ldx: $0006,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_4
jmp BlitTwoSprites
:loop_1_bit_4 lsr
bcc :loop_1_bit_5
ldx: $0008,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_5
jmp BlitTwoSprites
:loop_1_bit_5 lsr
bcc :loop_1_bit_6
ldx: $000A,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_6
jmp BlitTwoSprites
:loop_1_bit_6 lsr
bcc :loop_1_bit_7
ldx: $000C,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_7
jmp BlitTwoSprites
:loop_1_bit_7 lsr
bcc :loop_1_bit_8
ldx: $000E,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_8
jmp BlitTwoSprites
:loop_1_bit_8 lsr
bcc :loop_1_bit_9
ldx: $0010,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_9
jmp BlitTwoSprites
:loop_1_bit_9 lsr
bcc :loop_1_bit_10
ldx: $0012,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_10
jmp BlitTwoSprites
:loop_1_bit_10 lsr
bcc :loop_1_bit_11
ldx: $0014,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_11
jmp BlitTwoSprites
:loop_1_bit_11 lsr
bcc :loop_1_bit_12
ldx: $0016,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_12
jmp BlitTwoSprites
:loop_1_bit_12 lsr
bcc :loop_1_bit_13
ldx: $0018,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_13
jmp BlitTwoSprites
:loop_1_bit_13 lsr
bcc :loop_1_bit_14
ldx: $001A,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_14
jmp BlitTwoSprites
:loop_1_bit_14 lsr
bcc :loop_1_bit_15
ldx: $001C,y
stx spriteIdx+2
cmp #0
jne :loop_2_bit_15
jmp BlitTwoSprites
:loop_1_bit_15 ldx: $001E,y
stx spriteIdx+2
jmp BlitTwoSprites
:loop_2_bit_2 lsr
bcc :loop_2_bit_3
ldx: $0004,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_3
jmp BlitThreeSprites
:loop_2_bit_3 lsr
bcc :loop_2_bit_4
ldx: $0006,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_4
jmp BlitThreeSprites
:loop_2_bit_4 lsr
bcc :loop_2_bit_5
ldx: $0008,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_5
jmp BlitThreeSprites
:loop_2_bit_5 lsr
bcc :loop_2_bit_6
ldx: $000A,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_6
jmp BlitThreeSprites
:loop_2_bit_6 lsr
bcc :loop_2_bit_7
ldx: $000C,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_7
jmp BlitThreeSprites
:loop_2_bit_7 lsr
bcc :loop_2_bit_8
ldx: $000E,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_8
jmp BlitThreeSprites
:loop_2_bit_8 lsr
bcc :loop_2_bit_9
ldx: $0010,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_9
jmp BlitThreeSprites
:loop_2_bit_9 lsr
bcc :loop_2_bit_10
ldx: $0012,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_10
jmp BlitThreeSprites
:loop_2_bit_10 lsr
bcc :loop_2_bit_11
ldx: $0014,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_11
jmp BlitThreeSprites
:loop_2_bit_11 lsr
bcc :loop_2_bit_12
ldx: $0016,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_12
jmp BlitThreeSprites
:loop_2_bit_12 lsr
bcc :loop_2_bit_13
ldx: $0018,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_13
jmp BlitThreeSprites
:loop_2_bit_13 lsr
bcc :loop_2_bit_14
ldx: $001A,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_14
jmp BlitThreeSprites
:loop_2_bit_14 lsr
bcc :loop_2_bit_15
ldx: $001C,y
stx spriteIdx+4
cmp #0
jne :loop_3_bit_15
jmp BlitThreeSprites
:loop_2_bit_15 ldx: $001E,y
stx spriteIdx+4
jmp BlitThreeSprites
:loop_3_bit_3 lsr
bcc :loop_3_bit_4
ldx $0006,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_4 lsr
bcc :loop_3_bit_5
ldx $0008,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_5 lsr
bcc :loop_3_bit_6
ldx $000A,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_6 lsr
bcc :loop_3_bit_7
ldx $000C,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_7 lsr
bcc :loop_3_bit_8
ldx $000E,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_8 lsr
bcc :loop_3_bit_9
ldx $0010,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_9 lsr
bcc :loop_3_bit_10
ldx $0012,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_10 lsr
bcc :loop_3_bit_11
ldx $0014,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_11 lsr
bcc :loop_3_bit_12
ldx $0016,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_12 lsr
bcc :loop_3_bit_13
ldx $0018,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_13 lsr
bcc :loop_3_bit_14
ldx $001A,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_14 lsr
bcc :loop_3_bit_15
ldx $001C,y
stx spriteIdx+6
jmp BlitFourSprites
:loop_3_bit_15 ldx $001E,y
stx spriteIdx+6
jmp BlitFourSprites
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DirtyTileProcs dw _TBDirtyTile_00,_TBDirtyTile_0H,_TBDirtyTile_V0,_TBDirtyTile_VH
;DirtyTileSpriteProcs dw _TBDirtySpriteTile_00,_TBDirtySpriteTile_0H,_TBDirtySpriteTile_V0,_TBDirtySpriteTile_VH
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; Blit tiles directly to the screen.
_TBDirtyTile_00
_TBDirtyTile_0H
]line equ 0
lup 8
ldal tiledata+{]line*4},x
sta: $0000+{]line*160},y
ldal tiledata+{]line*4}+2,x
sta: $0002+{]line*160},y
]line equ ]line+1
--^
rts
_TBDirtyTile_V0
_TBDirtyTile_VH
]src equ 7
]dest equ 0
lup 8
ldal tiledata+{]src*4},x
sta: $0000+{]dest*160},y
ldal tiledata+{]src*4}+2,x
sta: $0002+{]dest*160},y
]src equ ]src-1
]dest equ ]dest+1
--^
rts
; If there are two or more sprites at a tile, we can still be fast, but need to do extra work because
; the VBUFF values need to be read from the direct page. Thus, the direct page cannot be mapped onto
; the graphics screen. We use the stack instead, but have to do extra work to save and restore the
; stack value.
BlitFourSprites
BlitThreeSprites
BlitTwoSprites
plb
tsc
sta stkSave ; Save the stack on the direct page
sei
clc
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ldy tileAddr
lda screenAddr ; Saved in direct page locations
tcs
_R0W1
lda tiledata+{0*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{0*SPRITE_PLANE_SPAN},x
oral spritedata+{0*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{0*SPRITE_PLANE_SPAN},x
oral spritedata+{0*SPRITE_PLANE_SPAN},x
sta $00,s
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lda tiledata+{0*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{0*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{0*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{0*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{0*SPRITE_PLANE_SPAN}+2,x
sta $02,s
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lda tiledata+{1*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{1*SPRITE_PLANE_SPAN},x
oral spritedata+{1*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{1*SPRITE_PLANE_SPAN},x
oral spritedata+{1*SPRITE_PLANE_SPAN},x
sta $A0,s
lda tiledata+{1*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{1*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{1*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{1*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{1*SPRITE_PLANE_SPAN}+2,x
sta $A2,s
tsc
adc #320
tcs
lda tiledata+{2*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{2*SPRITE_PLANE_SPAN},x
oral spritedata+{2*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{2*SPRITE_PLANE_SPAN},x
oral spritedata+{2*SPRITE_PLANE_SPAN},x
sta $00,s
lda tiledata+{2*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{2*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{2*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{2*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{2*SPRITE_PLANE_SPAN}+2,x
sta $02,s
lda tiledata+{3*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{3*SPRITE_PLANE_SPAN},x
oral spritedata+{3*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{3*SPRITE_PLANE_SPAN},x
oral spritedata+{3*SPRITE_PLANE_SPAN},x
sta $A0,s
lda tiledata+{3*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{3*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{3*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{3*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{3*SPRITE_PLANE_SPAN}+2,x
sta $A2,s
tsc
adc #320
tcs
lda tiledata+{4*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{4*SPRITE_PLANE_SPAN},x
oral spritedata+{4*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{4*SPRITE_PLANE_SPAN},x
oral spritedata+{4*SPRITE_PLANE_SPAN},x
sta $00,s
lda tiledata+{4*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{4*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{4*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{4*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{4*SPRITE_PLANE_SPAN}+2,x
sta $02,s
lda tiledata+{5*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{5*SPRITE_PLANE_SPAN},x
oral spritedata+{5*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{5*SPRITE_PLANE_SPAN},x
oral spritedata+{5*SPRITE_PLANE_SPAN},x
sta $A0,s
lda tiledata+{5*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{5*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{5*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{5*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{5*SPRITE_PLANE_SPAN}+2,x
sta $A2,s
tsc
adc #320
tcs
lda tiledata+{6*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{6*SPRITE_PLANE_SPAN},x
oral spritedata+{6*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{6*SPRITE_PLANE_SPAN},x
oral spritedata+{6*SPRITE_PLANE_SPAN},x
sta $00,s
lda tiledata+{6*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{6*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{6*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{6*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{6*SPRITE_PLANE_SPAN}+2,x
sta $02,s
lda tiledata+{7*TILE_DATA_SPAN},y
ldx spriteIdx+2
andl spritemask+{7*SPRITE_PLANE_SPAN},x
oral spritedata+{7*SPRITE_PLANE_SPAN},x
ldx spriteIdx
andl spritemask+{7*SPRITE_PLANE_SPAN},x
oral spritedata+{7*SPRITE_PLANE_SPAN},x
sta $A0,s
lda tiledata+{7*TILE_DATA_SPAN}+2,y
ldx spriteIdx+2
andl spritemask+{7*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{7*SPRITE_PLANE_SPAN}+2,x
ldx spriteIdx
andl spritemask+{7*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{7*SPRITE_PLANE_SPAN}+2,x
sta $A2,s
_R0W0
lda stkSave
tcs
cli
rts
; There is only one sprite at this tile, so do a fast blit that directly combines a tile with a single
; sprite and renders directly to the screen
;
; NOTE: Expect X-register to already have been set to the correct VBUFF address
BlitOneSprite
ldy tileAddr ; load the address of this tile's data
lda screenAddr ; Get the on-screen address of this tile
plb
phd
sei
clc
tcd
_R0W1
lda tiledata+{0*TILE_DATA_SPAN},y
andl spritemask+{0*SPRITE_PLANE_SPAN},x
oral spritedata+{0*SPRITE_PLANE_SPAN},x
sta $00
lda tiledata+{0*TILE_DATA_SPAN}+2,y
andl spritemask+{0*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{0*SPRITE_PLANE_SPAN}+2,x
sta $02
lda tiledata+{1*TILE_DATA_SPAN},y
andl spritemask+{1*SPRITE_PLANE_SPAN},x
oral spritedata+{1*SPRITE_PLANE_SPAN},x
sta $A0
lda tiledata+{1*TILE_DATA_SPAN}+2,y
andl spritemask+{1*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{1*SPRITE_PLANE_SPAN}+2,x
sta $A2
tdc
adc #320
tcd
lda tiledata+{2*TILE_DATA_SPAN},y
andl spritemask+{2*SPRITE_PLANE_SPAN},x
oral spritedata+{2*SPRITE_PLANE_SPAN},x
sta $00
lda tiledata+{2*TILE_DATA_SPAN}+2,y
andl spritemask+{2*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{2*SPRITE_PLANE_SPAN}+2,x
sta $02
lda tiledata+{3*TILE_DATA_SPAN},y
andl spritemask+{3*SPRITE_PLANE_SPAN},x
oral spritedata+{3*SPRITE_PLANE_SPAN},x
sta $A0
lda tiledata+{3*TILE_DATA_SPAN}+2,y
andl spritemask+{3*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{3*SPRITE_PLANE_SPAN}+2,x
sta $A2
tdc
adc #320
tcd
lda tiledata+{4*TILE_DATA_SPAN},y
andl spritemask+{4*SPRITE_PLANE_SPAN},x
oral spritedata+{4*SPRITE_PLANE_SPAN},x
sta $00
lda tiledata+{4*TILE_DATA_SPAN}+2,y
andl spritemask+{4*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{4*SPRITE_PLANE_SPAN}+2,x
sta $02
lda tiledata+{5*TILE_DATA_SPAN},y
andl spritemask+{5*SPRITE_PLANE_SPAN},x
oral spritedata+{5*SPRITE_PLANE_SPAN},x
sta $A0
lda tiledata+{5*TILE_DATA_SPAN}+2,y
andl spritemask+{5*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{5*SPRITE_PLANE_SPAN}+2,x
sta $A2
tdc
adc #320
tcd
lda tiledata+{6*TILE_DATA_SPAN},y
andl spritemask+{6*SPRITE_PLANE_SPAN},x
oral spritedata+{6*SPRITE_PLANE_SPAN},x
sta $00
lda tiledata+{6*TILE_DATA_SPAN}+2,y
andl spritemask+{6*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{6*SPRITE_PLANE_SPAN}+2,x
sta $02
lda tiledata+{7*TILE_DATA_SPAN},y
andl spritemask+{7*SPRITE_PLANE_SPAN},x
oral spritedata+{7*SPRITE_PLANE_SPAN},x
sta $A0
lda tiledata+{7*TILE_DATA_SPAN}+2,y
andl spritemask+{7*SPRITE_PLANE_SPAN}+2,x
oral spritedata+{7*SPRITE_PLANE_SPAN}+2,x
sta $A2
_R0W0
cli
pld
rts