mirror of
https://github.com/lscharen/iigs-game-engine.git
synced 2024-06-28 14:29:32 +00:00
First draft of masked tile support
Need to have the called provide a copy of the base line address to the masked drawing code and need to verify that the JTable entries are ordered the same way as the byte offset so the same register can be used to load the JMP addresses and patch in the LDA (DP),y instructions.
This commit is contained in:
Lucas Scharenbroich
parent
e3cb742626
commit
90124b04bc
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@ -113,6 +113,64 @@ _Err mac
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NoErr eom
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; MAcros to use in the Masked Tile renderer
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CopyMaskedWord MAC
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ldal ]2,x ; load the mask value
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bne mixed ; a non-zero value may be mixed
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; This is a solid word
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lda #$00F4 ; PEA instruction
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sta: ]3,y
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ldal ]1,x ; load the tile data
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sta: ]3+1,y ; PEA operand
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bra next
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mixed cmp #$FFFF ; All 1's in the mask is fully transparent
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beq transparent
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; This is the slowest path because there is a *lot* of work to do. So much that it's
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; worth it to change up the environment to optimize things a bit more.
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lda #$004C ; JMP instruction
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sta: ]3,y
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ldx _X_REG ; Get the addressing offset
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ldal JTableOffset,x ; Get the address offset and add to the base address
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adc _BASE_ADDR ; of the current code field line (could be an ORA, too)
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sta: ]3+1,y
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tay ; This becomes the new address that we use to patch in
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txa ; Get the offset and render a LDA (dp),y instruction
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xba
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ora #$00B1
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sta: $0000,y
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ldx _T_PTR ; restore the original x-register value
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ldal ]1,x ; insert the tile mask and data into the exception
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sta: $0003,y ; handler.
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ldal ]2,x
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sta: $0006,y
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ldy _Y_REG ; restore original y-register value and move on
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bra next
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; This is a transparent word, so just show the second background layer
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transparent
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lda #$00B1 ; LDA (dp),y instruction
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sta: ]3,y
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lda _X_REG ; X is the logical tile offset (0, 2, 4, ... 82) left-to-right
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ora #$4800 ; put a PHA after the offset
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sta: ]3+1,y
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next
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eom
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@ -314,7 +314,7 @@ _UpdateBG0TileMap
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ldx :BlkX
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ldy :BlkY
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jsr CopyTile
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jsr RenderTile
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lda :BlkX
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inc
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@ -469,5 +469,6 @@ _UpdateBG0TileMap
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@ -55,6 +55,7 @@ Next equ 78
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BankLoad equ 128
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tiletmp equ 186 ; 8 bytes of temp storage for the tile renderers
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blttmp equ 192 ; 32 bytes of local cache/scratch space
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tmp8 equ 224
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@ -82,3 +83,4 @@ DIRTY_BIT_BG1_Y equ $0008
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DIRTY_BIT_BG0_REFRESH equ $0010
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DIRTY_BIT_BG1_REFRESH equ $0020
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@ -8,51 +8,63 @@
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; CopyTileLinear -- copies the tile data from the tile bank in linear order, e.g.
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; 32 consecutive bytes are copied
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; CopyTile
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; RenderTile
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;
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; A low-level function that copies 8x8 tiles directly into the code field space.
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; A high-level function that takes a 16-bit tile descriptor and dispatched to the
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; appropriate tile copy courinte based on the descritor flags
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;
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; Bit 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
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; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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; |xx|xx|xx|MM|DD|VV|HH| | | | | | | | | |
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; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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; \_______/ | | | | \________________________/
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; | | | | | Tile ID (0 to 511)
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; | | | | |
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; | | | | +-- H : Flip tile horizontally
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; | | | +----- V : Flip tile vertically
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; | | +-------- D : Render as a Dynamic Tile (Tile ID < 32, V and H have no effect)
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; | +----------- M : Apply tile mask
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; +----------------- Reserved
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;
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; A = Tile ID (0 - 1023)
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; X = Tile column (0 - 40)
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; Y = Tile row (0 - 25)
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CopyTile
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phb ; save the current bank
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phx ; save the original x-value
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pha ; save the tile ID
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tya ; lookup the address of the virtual line (y * 8)
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asl
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asl
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asl
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asl
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tay
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TILE_ID_MASK equ $01FF
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TILE_MASK_BIT equ $1000
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TILE_DYN_BIT equ $0800
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TILE_VFLIP_BIT equ $0400
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TILE_HFLIP_BIT equ $0200
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TILE_CTRL_MASK equ $1E00
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sep #$20 ; set the bank register
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lda BTableHigh,y
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pha ; save for a few instruction
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rep #$20
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; On entry
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;
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; B is set to the correct code field bank
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; A is set to the the tile descriptor
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; Y is set to the top-left address of the tile in the code field
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; X is set to the tile word offset (0 through 80 in steps of 4)
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;
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; tmp0/tmp1 is reserved
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RenderTile
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bit #TILE_CTRL_MASK ; Fast path for "normal" tiles
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beq _CopyTile
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cmp #TILE_MASK_BIT ; Tile 0 w/mask bit set is special, too
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bne *+5
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brl ClearTile
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phx ; Reverse the tile index since x = 0 is at the end
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lda #40
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sec
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sbc 1,s
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plx
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phx ; Save the tile offset
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asl ; there are two columns per tile, so multiple by 4
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asl ; asl will clear the carry bit
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tax
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lda Col2CodeOffset,x
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clc
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adc BTableLow,y
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tay
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and #TILE_ID_MASK ; Mask out the ID and save just tha
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pha
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plb ; set the bank
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pla ; pop the tile ID
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jsr :CopyTileMem0
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txa
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and #TILE_CTRL_MASK ; Mask out the different modifiers
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xba
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tax
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jmp (:actions,x)
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plx ; pop the x-register
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plb ; restore the data bank and return
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rts
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:actions dw solid,solid_hflip,solid_vflip,solid_hvflip
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dw dynamic,dynamic,dynamic,dynamic
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dw masked,masked_hflip,masked_vflip,masked_hvflip
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dw dyn_masked,dyn_masked,dyn_masked,dyn_masked
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; _CopyTile
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;
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@ -62,21 +74,31 @@ CopyTile
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; A = Tile ID (0 - 1023)
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; Y = Base Adddress in the code field
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:_CopyTile cmp #$0010
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bcs *+5
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brl :FillWord
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cmp #$0400
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bcs *+5
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brl :CopyTileMem
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rts ; Tile number is too large
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_CopyTile cmp #$0000 ; Fast-path the special zero tile
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bne CopyTileMem
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:TilePatterns dw $0000,$1111,$2222,$3333
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dw $4444,$5555,$6666,$7777
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dw $8888,$9999,$AAAA,$BBBB
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dw $CCCC,$DDDD,$EEEE,$FFFF
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FillWord0
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sta: $0001,y
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sta: $0004,y
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sta $1001,y
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sta $1004,y
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sta $2001,y
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sta $2004,y
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sta $3001,y
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sta $3004,y
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sta $4001,y
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sta $4004,y
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sta $5001,y
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sta $5004,y
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sta $6001,y
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sta $6004,y
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sta $7001,y
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sta $7004,y ; Fall through here intentionally
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:ClearTile sep #$20
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lda #$B1
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; For solid tiles
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FillPEAOpcode
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sep #$20
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lda #$F4
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sta: $0000,y
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sta: $0003,y
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sta $1000,y
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@ -94,60 +116,12 @@ CopyTile
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sta $7000,y
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sta $7003,y
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rep #$20
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lda 3,s
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asl
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asl
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and #$00FF
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ora #$4800
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sta: $0004,y
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sta $1004,y
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sta $2004,y
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sta $3004,y
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sta $4004,y
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sta $5004,y
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sta $6004,y
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sta $7004,y
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inc
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inc
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sta: $0001,y
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sta $1001,y
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sta $2001,y
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sta $3001,y
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sta $4001,y
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sta $5001,y
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sta $6001,y
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sta $7001,y
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rts
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:FillWord asl
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tax
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ldal :TilePatterns,x
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sta: $0001,y
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sta: $0004,y
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sta $1001,y
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sta $1004,y
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sta $2001,y
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sta $2004,y
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sta $3001,y
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sta $3004,y
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sta $4001,y
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sta $4004,y
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sta $5001,y
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sta $5004,y
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sta $6001,y
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sta $6004,y
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sta $7001,y
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sta $7004,y
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rts
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:CopyTileMem sec
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sbc #$0010
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:CopyTileMem0
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asl
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CopyTileMem
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CopyTileMem0
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asl ; Each tile takes up 64 bytes, 32 bytes for the
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asl ; 8x8 data and 32 bytes for the 8x8 mask.
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asl
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asl
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asl
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@ -188,6 +162,155 @@ CopyTile
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sta $7001,y
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rts
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; Masked tiles
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;
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; Can result in one or three different code sequences
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;
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; If mask === $0000, then insert PEA $DATA
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; If mask === $FFFF, then insert LDA (DP),y / PHA
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; Else then insert JMP and patch exception handler
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;
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; Because every word of the tile can lead to different opcodes, we
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; do the entire setup for each word rather than breaking them up into
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; 16-bit and 8-bit operations.
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; Macro to make the loop simpler. Takes three arguments
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;
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; ]1 = address of tile data
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; ]2 = address of tile mask
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; ]3 = address of target in code field
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;
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; This is a relatively efficient way to handle the three different modes. Focus on this and
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; then we will adjust the setup code...
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CopyTileMemM
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_X_REG equ tiletmp
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_Y_REG equ tiletmp+2
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_T_PTR equ tiletmp+4 ; Copy of the tile address pointer
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_BASE_ADDR equ tiletmp+6 ; Copy of BTableLow for this tile
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stx _X_REG ; Save these values as we will need to reload them
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sty _Y_REG ; at certain points
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asl ; Each tile takes up 64 bytes, 32 bytes for the
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asl ; 8x8 data and 32 bytes for the 8x8 mask.
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asl
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asl
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asl
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asl
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sta _T_PTR
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tax
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CopyMaskedWord tiledata+0;tiledata+32+0;$0003
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CopyMaskedWord tiledata+2;tiledata+32+2;$0000
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CopyMaskedWord tiledata+4;tiledata+32+4;$1003
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CopyMaskedWord tiledata+6;tiledata+32+6;$1000
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CopyMaskedWord tiledata+8;tiledata+32+8;$2003
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CopyMaskedWord tiledata+10;tiledata+32+10;$2000
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CopyMaskedWord tiledata+12;tiledata+32+12;$3003
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CopyMaskedWord tiledata+14;tiledata+32+14;$3000
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CopyMaskedWord tiledata+16;tiledata+32+16;$4003
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CopyMaskedWord tiledata+18;tiledata+32+18;$4000
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CopyMaskedWord tiledata+20;tiledata+32+20;$5003
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CopyMaskedWord tiledata+22;tiledata+32+22;$5000
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CopyMaskedWord tiledata+24;tiledata+32+24;$6003
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CopyMaskedWord tiledata+28;tiledata+32+26;$6000
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CopyMaskedWord tiledata+30;tiledata+32+28;$7003
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CopyMaskedWord tiledata+32;tiledata+32+30;$7000
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rts
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TilePatterns dw $0000,$1111,$2222,$3333
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dw $4444,$5555,$6666,$7777
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dw $8888,$9999,$AAAA,$BBBB
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dw $CCCC,$DDDD,$EEEE,$FFFF
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ClearTile sep #$20
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lda #$B1 ; This is a special case where we can set all the words to LDA (DP),y
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sta: $0000,y
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sta: $0003,y
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sta $1000,y
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sta $1003,y
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sta $2000,y
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sta $2003,y
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sta $3000,y
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sta $3003,y
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sta $4000,y
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sta $4003,y
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sta $5000,y
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sta $5003,y
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sta $6000,y
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sta $6003,y
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sta $7000,y
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sta $7003,y
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rep #$20
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txa
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and #$00FF
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ora #$4800
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sta: $0004,y
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sta $1004,y
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sta $2004,y
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sta $3004,y
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sta $4004,y
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sta $5004,y
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sta $6004,y
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sta $7004,y
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inc
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inc
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sta: $0001,y
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sta $1001,y
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sta $2001,y
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sta $3001,y
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sta $4001,y
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sta $5001,y
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sta $6001,y
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sta $7001,y
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rts
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; Copy a tile, but vertically flip the data
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CopyTileMemV
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asl ; Each tile takes up 64 bytes, 32 bytes for the
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asl ; 8x8 data and 32 bytes for the 8x8 mask.
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asl
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asl
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asl
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asl
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tax
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ldal tiledata+0,x ; The low word goes in the *next* instruction
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sta $7004,y
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ldal tiledata+2,x
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sta $7001,y
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ldal tiledata+4,x
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sta $6004,y
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ldal tiledata+6,x
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sta $6001,y
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ldal tiledata+8,x
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sta $5004,y
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ldal tiledata+10,x
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sta $5001,y
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ldal tiledata+12,x
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sta $4004,y
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ldal tiledata+14,x
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sta $4001,y
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ldal tiledata+16,x
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sta $3004,y
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ldal tiledata+18,x
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sta $3001,y
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ldal tiledata+20,x
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sta $2004,y
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ldal tiledata+22,x
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sta $2001,y
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ldal tiledata+24,x
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sta $1004,y
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ldal tiledata+26,x
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sta $1001,y
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ldal tiledata+28,x
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sta: $0004,y
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ldal tiledata+30,x
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sta: $0001,y
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rts
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; Primitives to render a dynamic tile
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;
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; LDA 00,x / PHA where the operand is fixed when the tile is rendered
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@ -195,7 +318,7 @@ CopyTile
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;
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; A = dynamic tile id (must be an 8-bit value)
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:DynTile
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DynTile
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and #$00FF
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ora #$4800
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sta: $0004,y
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@ -239,6 +362,86 @@ CopyTile
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rts
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; This should never be called, because empty control value should be fast-pathed
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solid
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plx
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pla
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rts
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; Not implemented yet, fallback to regular tile rendering
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solid_hflip
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plx
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pla
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brl CopyTileMem
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solid_vflip
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plx
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pla
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brl CopyTileMemV
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; Not implemented, fallback to just vertical flips
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solid_hvflip
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plx
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pla
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brl CopyTileMemV
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masked
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plx
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pla
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brl CopyTileMemM
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masked_hflip
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masked_vflip
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masked_hvflip
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dynamic
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dyn_masked
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rts
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; CopyTile
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;
|
||||
; A low-level function that copies 8x8 tiles directly into the code field space.
|
||||
;
|
||||
; A = Tile ID (0 - 1023)
|
||||
; X = Tile column (0 - 40)
|
||||
; Y = Tile row (0 - 25)
|
||||
CopyTile
|
||||
phb ; save the current bank
|
||||
phx ; save the original x-value
|
||||
pha ; save the tile ID
|
||||
|
||||
tya ; lookup the address of the virtual line (y * 8)
|
||||
asl
|
||||
asl
|
||||
asl
|
||||
asl
|
||||
tay
|
||||
|
||||
sep #$20 ; set the bank register
|
||||
lda BTableHigh,y
|
||||
pha ; save for a few instruction
|
||||
rep #$20
|
||||
|
||||
phx ; Reverse the tile index since x = 0 is at the end
|
||||
lda #40
|
||||
sec
|
||||
sbc 1,s
|
||||
plx
|
||||
|
||||
asl ; there are two columns per tile, so multiple by 4
|
||||
asl ; asl will clear the carry bit
|
||||
tax
|
||||
lda Col2CodeOffset,x
|
||||
clc
|
||||
adc BTableLow,y
|
||||
tay
|
||||
|
||||
plb ; set the bank
|
||||
pla ; pop the tile ID
|
||||
jsr CopyTileMem0
|
||||
|
||||
plx ; pop the x-register
|
||||
plb ; restore the data bank and return
|
||||
rts
|
||||
|
||||
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user