937 lines
38 KiB
ArmAsm
937 lines
38 KiB
ArmAsm
; Collection of functions that deal with tiles. Primarily rendering tile data into
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; the code fields.
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;
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; Tile data can be done faily often, so these routines are performance-sensitive.
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;
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; CopyTileConst -- the first 16 tile numbers are reserved and can be used
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; to draw a solid tile block
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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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; _RenderTile
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;
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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 routine based on the descriptor 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|FF|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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; | +-------------- F : Overlay a fringe tile
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; +------------------- Reserved (must be zero)
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;
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; Each logical tile (corresponding to each Tile ID) actually takes up 128 bytes of memory in the
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; tile bank
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;
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; +0 : 32 bytes of tile data
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; +32 : 32 bytes of tile mask
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; +64 : 32 bytes of horizontally flipped tile data
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; +96 : 32 bytes of horizontally flipped tile mask
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;
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; It is simply too slow to try to horizontally reverse the pixel data on the fly. This still allows
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; for up to 512 tiles to be stored in a single bank, which should be sufficient.
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; Use some temporary space for the spriteIdx array (maximum of 4 entries)
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stkSave equ tmp9
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screenAddr equ tmp10
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tileAddr equ tmp11
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spriteIdx equ tmp12
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; Given an address to a Tile Store record, dispatch to the appropriate tile renderer. The Tile
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; Store record contains all of the low-level information that's needed to call the renderer.
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;
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; There are two execution paths that are handled here. First, if there is no sprite, then
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; the tile data is read directly and written into the code field in a single pass. If there
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; are sprites that overlap the tile, then the sprite data is combined with the tile data
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; and written to a temporary direct page buffer. If
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;
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; This routine sets the direct page register to the second page since we use that space to
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; build and cache tile and sprite data, when necessary
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_RenderTile2
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lda TileStore+TS_SPRITE_FLAG,x ; This is a bitfield of all the sprites that intersect this tile, only care if non-zero or not
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bne do_dirty_sprite
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; Handle the non-sprite tile blit
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CopyNoSprites
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sep #$20
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lda TileStore+TS_CODE_ADDR_HIGH,x ; load the bank of the target code field line
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pha ; and put on the stack for later
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lda TileStore+TS_BASE_ADDR+1,x ; load the base address of the code field ($0000 or $8000)
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sta _BASE_ADDR+1 ; so we can get by just copying the high byte
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rep #$20
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lda TileStore+TS_BASE_TILE_DISP,x ; Get the address of the renderer for this tile
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stal :tiledisp+1
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lda TileStore+TS_TILE_ID,x
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sta _TILE_ID ; Some tile blitters need to get the tile descriptor
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ldy TileStore+TS_CODE_ADDR_LOW,x ; load the address of the code field
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lda TileStore+TS_TILE_ADDR,x ; load the address of this tile's data (pre-calculated)
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pha
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lda TileStore+TS_WORD_OFFSET,x
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plx
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plb ; set the bank to the code field that will be updated
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; B is set to the correct code field bank
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; A is set to the tile word offset (0 through 80 in steps of 4)
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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 address of the tile data
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:tiledisp jmp $0000 ; render the tile
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; Let's make a macro helper for the bit test tree
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; dobit src_offset,dest,next_target,end_target
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dobit MAC
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beq last_bit
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ldx: ]1,y
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stx ]2
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jmp ]3
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last_bit ldx: ]1,y
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stx ]2
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jmp ]4
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EOM
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; The sprite code is just responsible for quickly copying all of the sprite data
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; into the direct page temp area.
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do_dirty_sprite
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pei TileStoreBankAndTileDataBank ; Special value that has the TileStore bank in LSB and TileData bank in MSB
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plb
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; Cache a couple of values into the direct page that are used across all copy routines
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lda TileStore+TS_TILE_ADDR,y ; load the address of this tile's data (pre-calculated)
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sta tileAddr
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ldx TileStore+TS_VBUFF_ADDR_COUNT,y
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jmp (dirty_sprite_dispatch,x)
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dirty_sprite_dispatch
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da CopyNoSprites
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da CopyOneSprite
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da CopyTwoSprites
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da CopyThreeSprites
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da CopyFourSprites ; MAX, don't bother with more than 4 sprites per tile
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; This is very similar to the code in the dirty tile renderer, but we can't reuse
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; because that code draws directly to the graphics screen, and this code draws
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; to a temporary budder that has a different stride.
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; ldy TileStore+TS_VBUFF_ARRAY_ADDR,x ; base address of the VBUFF sprite address array for this tile
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;
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; lsr
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; bcc :loop_0_bit_1
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; dobit $0000;sprite_ptr0;:loop_1_bit_1;CopyOneSprite
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;:loop_0_bit_1 lsr
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; bcc :loop_0_bit_2
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; dobit $0002;sprite_ptr0;:loop_1_bit_2;CopyOneSprite
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;:loop_0_bit_2 lsr
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; bcc :loop_0_bit_3
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; dobit $0004;sprite_ptr0;:loop_1_bit_3;CopyOneSprite
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;:loop_0_bit_3 lsr
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; bcc :loop_0_bit_4
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; dobit $0006;sprite_ptr0;:loop_1_bit_4;CopyOneSprite
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;:loop_0_bit_4 lsr
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; bcc :loop_0_bit_5
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; dobit $0008;sprite_ptr0;:loop_1_bit_5;CopyOneSprite
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;:loop_0_bit_5 lsr
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; bcc :loop_0_bit_6
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; dobit $000A;sprite_ptr0;:loop_1_bit_6;CopyOneSprite
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;:loop_0_bit_6 lsr
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; bcc :loop_0_bit_7
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; dobit $000C;sprite_ptr0;:loop_1_bit_7;CopyOneSprite
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;:loop_0_bit_7 lsr
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; bcc :loop_0_bit_8
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; dobit $000E;sprite_ptr0;:loop_1_bit_8;CopyOneSprite
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;:loop_0_bit_8 lsr
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; bcc :loop_0_bit_9
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; dobit $0010;sprite_ptr0;:loop_1_bit_9;CopyOneSprite
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;:loop_0_bit_9 lsr
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; bcc :loop_0_bit_10
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; ldx: $0012,y
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; stx spriteIdx
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; cmp #0
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; jne :loop_1_bit_10
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; jmp CopyOneSprite
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;:loop_0_bit_10 lsr
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; bcc :loop_0_bit_11
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; dobit $0014;sprite_ptr0;:loop_1_bit_11;CopyOneSprite
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;:loop_0_bit_11 lsr
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; bcc :loop_0_bit_12
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; dobit $0016;sprite_ptr0;:loop_1_bit_12;CopyOneSprite
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;:loop_0_bit_12 lsr
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; bcc :loop_0_bit_13
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; dobit $0018;sprite_ptr0;:loop_1_bit_13;CopyOneSprite
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;:loop_0_bit_13 lsr
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; bcc :loop_0_bit_14
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; dobit $001A;sprite_ptr0;:loop_1_bit_14;CopyOneSprite
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;:loop_0_bit_14 lsr
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; bcc :loop_0_bit_15
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; dobit $001C;sprite_ptr0;:loop_1_bit_15;CopyOneSprite
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;:loop_0_bit_15 ldx: $001E,y
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; stx spriteIdx
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; jmp CopyOneSprite
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; We can optimize later, for now just copy the sprite data and mask into its own
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; direct page buffer and combine with the tile data later
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; We set up direct page pointers to the mask bank and use the bank register for the
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; data.
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CopyFourSprites
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lda TileStore+TS_VBUFF_ADDR_0,y
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sta spriteIdx
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lda TileStore+TS_VBUFF_ADDR_1,y
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sta spriteIdx+4
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lda TileStore+TS_VBUFF_ADDR_2,y
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sta spriteIdx+8
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lda TileStore+TS_VBUFF_ADDR_3,y
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sta spriteIdx+12
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; Copy three sprites into a temporary direct page buffer
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LDA_IL equ $A7 ; lda [dp]
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LDA_ILY equ $B7 ; lda [dp],y
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AND_IL equ $27 ; and [dp]
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AND_ILY equ $37 ; and [dp],y
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CopyThreeSprites
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lda TileStore+TS_VBUFF_ADDR_0,y
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sta spriteIdx
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lda TileStore+TS_VBUFF_ADDR_1,y
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sta spriteIdx+4
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lda TileStore+TS_VBUFF_ADDR_2,y
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sta spriteIdx+8
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]line equ 0
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lup 8
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ldy #]line*SPRITE_PLANE_SPAN
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lda (spriteIdx+8),y
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db AND_ILY,spriteIdx+4 ; Can't use long indirect inside LUP because of ']'
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ora (spriteIdx+4),y
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db AND_ILY,spriteIdx+0
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ora (spriteIdx+0),y
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sta tmp_sprite_data+{]line*4}
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db LDA_ILY,spriteIdx+8
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db AND_ILY,spriteIdx+4
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db AND_ILY,spriteIdx+0
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sta tmp_sprite_mask+{]line*4}
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ldy #]line*SPRITE_PLANE_SPAN+2
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lda (spriteIdx+8),y
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db AND_ILY,spriteIdx+4
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ora (spriteIdx+4),y
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db AND_ILY,spriteIdx+0
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ora (spriteIdx+0),y
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sta tmp_sprite_data+{]line*4}+2
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db LDA_ILY,spriteIdx+8
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db AND_ILY,spriteIdx+4
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db AND_ILY,spriteIdx+0
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sta tmp_sprite_mask+{]line*4}+2
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]line equ ]line+1
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--^
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; jmp FinishTile
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; Copy two sprites into a temporary direct page buffer
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CopyTwoSprites
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lda TileStore+TS_VBUFF_ADDR_0,y
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sta spriteIdx
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lda TileStore+TS_VBUFF_ADDR_1,y
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sta spriteIdx+4
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]line equ 0
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lup 8
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ldy #]line*SPRITE_PLANE_SPAN
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lda (spriteIdx+4),y
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db AND_ILY,spriteIdx+0
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ora (spriteIdx+0),y
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sta tmp_sprite_data+{]line*4}
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db LDA_ILY,spriteIdx+4
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db AND_ILY,spriteIdx+0
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sta tmp_sprite_mask+{]line*4}
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ldy #]line*SPRITE_PLANE_SPAN+2
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lda (spriteIdx+4),y
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db AND_ILY,spriteIdx+0
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ora (spriteIdx+0),y
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sta tmp_sprite_data+{]line*4}+2
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db LDA_ILY,spriteIdx+4
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db AND_ILY,spriteIdx+0
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sta tmp_sprite_mask+{]line*4}+2
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]line equ ]line+1
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--^
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; jmp FinishTile
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CopyOneSprite
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clc
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lda TileStore+TS_VBUFF_ADDR_0,y
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sta spriteIdx
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adc #2
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sta spriteIdx+4
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]line equ 0
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lup 8
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; ldal tiledata,x
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; and [spriteIdx]
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; ora (spriteIdx)
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; sta tmp_sprite_data+{]line*4}
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ldal spritedata+{]line*SPRITE_PLANE_SPAN},x
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sta tmp_sprite_data+{]line*4}
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ldal spritedata+{]line*SPRITE_PLANE_SPAN}+2,x
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sta tmp_sprite_data+{]line*4}+2
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ldal spritemask+{]line*SPRITE_PLANE_SPAN},x
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sta tmp_sprite_mask+{]line*4}
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ldal spritemask+{]line*SPRITE_PLANE_SPAN}+2,x
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sta tmp_sprite_mask+{]line*4}+2
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]line equ ]line+1
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--^
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; jmp FinishTile
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; Reference all of the tile rendering subroutines defined in the TileXXXXX files. Each file defines
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; 8 entry points:
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;
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; One set for normal, horizontally flipped, vertically flipped and hors & vert flipped.
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; A second set that are optimized for when EngineMode has BG1 disabled.
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TileProcs dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 00000 : normal tiles
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dw _TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00 ; 00001 : dynamic tiles
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dw _TBMaskedTile_00,_TBMaskedTile_0H,_TBMaskedTile_V0,_TBMaskedTile_VH ; 00010 : masked normal tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00 ; 00011 : masked dynamic tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00
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; Fringe tiles not supported yet, so just repeat the block from above
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 00100 : fringed normal tiles
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dw _TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00 ; 00101 : fringed dynamic tiles
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dw _TBMaskedTile_00,_TBMaskedTile_0H,_TBMaskedTile_V0,_TBMaskedTile_VH ; 00110 : fringed masked normal tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00 ; 00111 : fringed masked dynamic tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00
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; High-priority tiles without a sprite in front of them are just normal tiles. Repeat the top half
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 01000 : high-priority normal tiles
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dw _TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00 ; 01001 : high-priority dynamic tiles
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dw _TBMaskedTile_00,_TBMaskedTile_0H,_TBMaskedTile_V0,_TBMaskedTile_VH ; 01010 : high-priority masked normal tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00 ; 01011 : high-priority masked dynamic tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 01100 : high-priority fringed normal tiles
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dw _TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00,_TBDynamicTile_00 ; 01101 : high-priority fringed dynamic tiles
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dw _TBMaskedTile_00,_TBMaskedTile_0H,_TBMaskedTile_V0,_TBMaskedTile_VH ; 01110 : high-priority fringed masked normal tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00 ; 01111 : high-priority fringed masked dynamic tiles
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dw _TBDynamicMaskTile_00,_TBDynamicMaskTile_00
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; Here are all the sprite variants of the tiles
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dw _TBSolidSpriteTile_00,_TBSolidSpriteTile_0H
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dw _TBSolidSpriteTile_V0,_TBSolidSpriteTile_VH ; 10000 : normal tiles w/sprite
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dw _TBDynamicSpriteTile_00,_TBDynamicSpriteTile_00
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dw _TBDynamicSpriteTile_00,_TBDynamicSpriteTile_00 ; 10001 : dynamic tiles w/sprite
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dw _TBMaskedSpriteTile_00,_TBMaskedSpriteTile_0H
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dw _TBMaskedSpriteTile_V0,_TBMaskedSpriteTile_VH ; 10010 : masked normal tiles w/sprite
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dw _TBDynamicMaskedSpriteTile_00,_TBDynamicMaskedSpriteTile_00
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dw _TBDynamicMaskedSpriteTile_00,_TBDynamicMaskedSpriteTile_00 ; 10011 : masked dynamic tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 10100 : fringed normal tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 10101 : fringed dynamic tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 10110 : fringed masked normal tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 10111 : fringed masked dynamic tiles w/sprite
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dw _TBSolidPrioritySpriteTile_00,_TBSolidPrioritySpriteTile_0H,
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dw _TBSolidPrioritySpriteTile_V0,_TBSolidPrioritySpriteTile_VH ; 11000 : high-priority normal tiles w/sprite
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dw _TBDynamicPrioritySpriteTile_00,_TBDynamicPrioritySpriteTile_00
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dw _TBDynamicPrioritySpriteTile_00,_TBDynamicPrioritySpriteTile_00 ; 11001 : high-priority dynamic tiles w/sprite
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dw _TBMaskedPrioritySpriteTile_00,_TBMaskedPrioritySpriteTile_0H
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dw _TBMaskedPrioritySpriteTile_V0,_TBMaskedPrioritySpriteTile_VH ; 11010 : high-priority masked normal tiles w/sprite
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dw _TBDynamicMaskedPrioritySpriteTile_00,_TBDynamicMaskedPrioritySpriteTile_00
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dw _TBDynamicMaskedPrioritySpriteTile_00,_TBDynamicMaskedPrioritySpriteTile_00 ; 11011 : high-priority masked dynamic tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 11100 : high-priority fringed normal tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 11101 : high-priority fringed dynamic tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 11110 : high-priority fringed masked normal tiles w/sprite
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dw _TBSolidTile_00,_TBSolidTile_0H,_TBSolidTile_V0,_TBSolidTile_VH ; 11111 : high-priority fringed masked dynamic tiles w/sprite
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; _TBConstTile
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;
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; A specialized routine that fills in a tile with a single constant value. It's intended to be used to
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; fill in solid colors, so there are no specialized horizontal or verical flipped variants
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_TBConstTile
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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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jmp _TBFillPEAOpcode
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ClearTile
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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
|
|
sta $7004,y
|
|
inc
|
|
inc
|
|
sta: $0001,y
|
|
sta $1001,y
|
|
sta $2001,y
|
|
sta $3001,y
|
|
sta $4001,y
|
|
sta $5001,y
|
|
sta $6001,y
|
|
sta $7001,y
|
|
|
|
sep #$20
|
|
lda #$B1 ; This is a special case where we can set all the words to LDA (DP),y
|
|
sta: $0000,y
|
|
sta: $0003,y
|
|
sta $1000,y
|
|
sta $1003,y
|
|
sta $2000,y
|
|
sta $2003,y
|
|
sta $3000,y
|
|
sta $3003,y
|
|
sta $4000,y
|
|
sta $4003,y
|
|
sta $5000,y
|
|
sta $5003,y
|
|
sta $6000,y
|
|
sta $6003,y
|
|
sta $7000,y
|
|
sta $7003,y
|
|
rep #$20
|
|
rts
|
|
|
|
; Helper functions to copy tile data to the appropriate location in Bank 0
|
|
; X = tile ID
|
|
; Y = dynamic tile ID
|
|
CopyTileToDyn ENT
|
|
txa
|
|
jsr _GetTileAddr
|
|
tax
|
|
|
|
tya
|
|
and #$001F ; Maximum of 32 dynamic tiles
|
|
asl
|
|
asl ; 4 bytes per page
|
|
adc BlitterDP ; Add to the bank 00 base address
|
|
adc #$0100 ; Go to the next page
|
|
tay
|
|
jsr CopyTileDToDyn ; Copy the tile data
|
|
jsr CopyTileMToDyn ; Copy the tile mask
|
|
rtl
|
|
|
|
; X = address of tile
|
|
; Y = tile address in bank 0
|
|
CopyTileDToDyn
|
|
phb
|
|
pea $0000
|
|
plb
|
|
plb
|
|
|
|
ldal tiledata+0,x
|
|
sta: $0000,y
|
|
ldal tiledata+2,x
|
|
sta: $0002,y
|
|
ldal tiledata+4,x
|
|
sta $0100,y
|
|
ldal tiledata+6,x
|
|
sta $0102,y
|
|
ldal tiledata+8,x
|
|
sta $0200,y
|
|
ldal tiledata+10,x
|
|
sta $0202,y
|
|
ldal tiledata+12,x
|
|
sta $0300,y
|
|
ldal tiledata+14,x
|
|
sta $0302,y
|
|
ldal tiledata+16,x
|
|
sta $0400,y
|
|
ldal tiledata+18,x
|
|
sta $0402,y
|
|
ldal tiledata+20,x
|
|
sta $0500,y
|
|
ldal tiledata+22,x
|
|
sta $0502,y
|
|
ldal tiledata+24,x
|
|
sta $0600,y
|
|
ldal tiledata+26,x
|
|
sta $0602,y
|
|
ldal tiledata+28,x
|
|
sta $0700,y
|
|
ldal tiledata+30,x
|
|
sta $0702,y
|
|
|
|
plb
|
|
rts
|
|
|
|
; Helper function to copy tile mask to the appropriate location in Bank 0
|
|
;
|
|
; X = address of tile
|
|
; Y = tile address in bank 0
|
|
;
|
|
; Argument are the same as CopyTileDToDyn, the code takes care of adjust offsets.
|
|
; This make is possible to call the two functions back-to-back
|
|
;
|
|
; ldx tileAddr
|
|
; ldy dynTileAddr
|
|
; jsr CopyTileDToDyn
|
|
; jsr CopyTileMToDyn
|
|
CopyTileMToDyn
|
|
phb
|
|
pea $0000
|
|
plb
|
|
plb
|
|
|
|
ldal tiledata+32+0,x
|
|
sta: $0080,y
|
|
ldal tiledata+32+2,x
|
|
sta: $0082,y
|
|
ldal tiledata+32+4,x
|
|
sta $0180,y
|
|
ldal tiledata+32+6,x
|
|
sta $0182,y
|
|
ldal tiledata+32+8,x
|
|
sta $0280,y
|
|
ldal tiledata+32+10,x
|
|
sta $0282,y
|
|
ldal tiledata+32+12,x
|
|
sta $0380,y
|
|
ldal tiledata+32+14,x
|
|
sta $0382,y
|
|
ldal tiledata+32+16,x
|
|
sta $0480,y
|
|
ldal tiledata+32+18,x
|
|
sta $0482,y
|
|
ldal tiledata+32+20,x
|
|
sta $0580,y
|
|
ldal tiledata+32+22,x
|
|
sta $0582,y
|
|
ldal tiledata+32+24,x
|
|
sta $0680,y
|
|
ldal tiledata+32+26,x
|
|
sta $0682,y
|
|
ldal tiledata+32+28,x
|
|
sta $0780,y
|
|
ldal tiledata+32+30,x
|
|
sta $0782,y
|
|
|
|
plb
|
|
rts
|
|
|
|
; CopyBG0Tile
|
|
;
|
|
; A low-level function that copies 8x8 tiles directly into the code field space.
|
|
;
|
|
; A = Tile ID (0 - 511)
|
|
; X = Tile column (0 - 40)
|
|
; Y = Tile row (0 - 25)
|
|
CopyBG0Tile ENT
|
|
phb
|
|
phk
|
|
plb
|
|
jsr _CopyBG0Tile
|
|
plb
|
|
rtl
|
|
|
|
_CopyBG0Tile
|
|
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 ; x2 because the table contains words, not
|
|
tay
|
|
|
|
sep #$20 ; set the bank register
|
|
lda BTableHigh,y
|
|
pha ; save for a few instruction
|
|
rep #$20
|
|
|
|
txa
|
|
asl ; there are two columns per tile, so multiple by 4
|
|
asl ; asl will clear the carry bit
|
|
tax
|
|
|
|
lda BTableLow,y
|
|
sta _BASE_ADDR ; Used in masked tile renderer
|
|
clc
|
|
adc Col2CodeOffset+2,x ; Get the right edge (which is the lower physical address)
|
|
tay
|
|
|
|
plb ; set the bank
|
|
pla ; pop the tile ID
|
|
; jsr _RenderTile
|
|
|
|
:exit
|
|
plx ; pop the x-register
|
|
plb ; restore the data bank and return
|
|
rts
|
|
|
|
|
|
; CopyBG1Tile
|
|
;
|
|
; A low-level function that copies 8x8 tiles directly into the BG1 data buffer.
|
|
;
|
|
; A = Tile ID (0 - 511)
|
|
; X = Tile column (0 - 40)
|
|
; Y = Tile row (0 - 25)
|
|
CopyBG1Tile
|
|
phb
|
|
phk
|
|
plb
|
|
jsr _CopyBG1Tile
|
|
plb
|
|
rtl
|
|
|
|
_CopyBG1Tile
|
|
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
|
|
|
|
txa
|
|
asl
|
|
asl ; 4 bytes per tile column
|
|
clc
|
|
adc BG1YTable,y
|
|
tay
|
|
|
|
sep #$20
|
|
lda BG1DataBank
|
|
pha
|
|
plb ; set the bank
|
|
rep #$20
|
|
|
|
pla ; pop the tile ID
|
|
jsr _RenderTileBG1
|
|
|
|
plx ; pop the x-register
|
|
plb ; restore the data bank and return
|
|
rts
|
|
|
|
; Tile Store that holds tile records which contain all the essential information for rendering
|
|
; a tile.
|
|
;
|
|
; TileStore+TS_TILE_ID : Tile descriptor
|
|
; TileStore+TS_DIRTY : $0000 is clean, any other value indicated a dirty tile
|
|
; TileStore+TS_TILE_ADDR : Address of the tile in the tile data buffer
|
|
; TileStore+TS_CODE_ADDR_LOW : Low word of the address in the code field that receives the tile
|
|
; TileStore+TS_CODE_ADDR_HIGH : High word of the address in the code field that receives the tile
|
|
; TileStore+TS_WORD_OFFSET : Logical number of word for this location
|
|
; TileStore+TS_BASE_ADDR : Copy of BTableAddrLow
|
|
; TileStore+TS_SCREEN_ADDR : Address on the physical screen corresponding to this tile (for direct rendering)
|
|
; TileStore+TS_SPRITE_FLAG : A bit field of all sprites that intersect this tile
|
|
; TileStore+TS_SPRITE_ADDR_1 ; Address of the sprite data that aligns with this tile. These
|
|
; TileStore+TS_SPRITE_ADDR_2 ; values are 1:1 with the TS_SPRITE_FLAG bits and are not contiguous.
|
|
; TileStore+TS_SPRITE_ADDR_3 ; If the bit position in TS_SPRITE_FLAG is not set, then the value in
|
|
; TileStore+TS_SPRITE_ADDR_4 ; the TS_SPRITE_ADDR_* field is undefined.
|
|
; TileStore+TS_SPRITE_ADDR_5
|
|
; TileStore+TS_SPRITE_ADDR_6
|
|
; TileStore+TS_SPRITE_ADDR_7
|
|
; TileStore+TS_SPRITE_ADDR_8
|
|
; TileStore+TS_SPRITE_ADDR_9
|
|
; TileStore+TS_SPRITE_ADDR_10
|
|
; TileStore+TS_SPRITE_ADDR_11
|
|
; TileStore+TS_SPRITE_ADDR_12
|
|
; TileStore+TS_SPRITE_ADDR_13
|
|
; TileStore+TS_SPRITE_ADDR_14
|
|
; TileStore+TS_SPRITE_ADDR_15
|
|
; TileStore+TS_SPRITE_ADDR_16
|
|
|
|
|
|
; TileStore+
|
|
;TileStore ENT
|
|
; ds TILE_STORE_SIZE*11
|
|
|
|
; A list of dirty tiles that need to be updated in a given frame
|
|
DirtyTileCount ds 2
|
|
DirtyTiles ds TILE_STORE_SIZE ; At most this many tiles can possibly be update at once
|
|
|
|
_ClearDirtyTiles
|
|
bra :hop
|
|
:loop
|
|
jsr _PopDirtyTile
|
|
:hop
|
|
lda DirtyTileCount
|
|
bne :loop
|
|
rts
|
|
|
|
|
|
; Append a new dirty tile record
|
|
;
|
|
; A = result of _GetTileStoreOffset for X, Y
|
|
;
|
|
; The main purpose of this function is to
|
|
;
|
|
; 1. Avoid marking the same tile dirty multiple times, and
|
|
; 2. Pre-calculating all of the information necessary to render the tile
|
|
PushDirtyTile ENT
|
|
phb
|
|
phk
|
|
plb
|
|
jsr _PushDirtyTile
|
|
plb
|
|
rtl
|
|
|
|
; alternate version that is very slightly slower, but preserves the y-register
|
|
_PushDirtyTile
|
|
tax
|
|
|
|
; alternate entry point if the x-register is already set
|
|
_PushDirtyTileX
|
|
ldal TileStore+TS_DIRTY,x
|
|
bne :occupied2
|
|
|
|
inc ; any non-zero value will work
|
|
stal TileStore+TS_DIRTY,x ; and is 1 cycle faster than loading a constant value
|
|
|
|
txa
|
|
ldx DirtyTileCount ; 4
|
|
sta DirtyTiles,x ; 6
|
|
inx ; 2
|
|
inx ; 2
|
|
stx DirtyTileCount ; 4 = 18
|
|
rts
|
|
:occupied2
|
|
txa ; Make sure TileStore offset is returned in the accumulator
|
|
rts
|
|
|
|
; Remove a dirty tile from the list and return it in state ready to be rendered. It is important
|
|
; that the core rendering functions *only* use _PopDirtyTile to get a list of tiles to update,
|
|
; because this routine merges the tile IDs stored in the Tile Store with the Sprite
|
|
; information to set the TILE_SPRITE_BIT. This is the *only* place in the entire code base that
|
|
; applies this bit to a tile descriptor.
|
|
PopDirtyTile ENT
|
|
phb
|
|
phk
|
|
plb
|
|
jsr _PopDirtyTile
|
|
plb
|
|
rtl
|
|
|
|
_PopDirtyTile
|
|
ldy DirtyTileCount
|
|
bne _PopDirtyTile2
|
|
rts
|
|
|
|
_PopDirtyTile2 ; alternate entry point
|
|
dey
|
|
dey
|
|
sty DirtyTileCount ; remove last item from the list
|
|
|
|
ldx DirtyTiles,y ; load the offset into the Tile Store
|
|
lda #$FFFF
|
|
stal TileStore+TS_DIRTY,x ; clear the occupied backlink
|
|
rts
|
|
|
|
; Run through the dirty tile list and render them into the code field
|
|
ApplyTiles ENT
|
|
phb
|
|
phk
|
|
plb
|
|
jsr _ApplyTiles
|
|
plb
|
|
rtl
|
|
|
|
; The _ApplyTiles function is responsible for rendering all of the dirty tiles into the code
|
|
; field. In this function we switch to the second direct page which holds the temporary
|
|
; working buffers for tile rendering.
|
|
_ApplyTiles
|
|
tdc
|
|
clc
|
|
adc #$100 ; move to the next page
|
|
tcd
|
|
|
|
bra :begin
|
|
|
|
:loop
|
|
; Retrieve the offset of the next dirty Tile Store items in the X-register
|
|
|
|
jsr _PopDirtyTile2
|
|
|
|
; Call the generic dispatch with the Tile Store record pointer at by the X-register.
|
|
|
|
phb
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
; Loop again until the list of dirty tiles is empty
|
|
|
|
:begin ldy DirtyTileCount
|
|
bne :loop
|
|
|
|
tdc ; Move back to the original direct page
|
|
sec
|
|
sbc #$100
|
|
tcd
|
|
rts
|
|
|
|
; To make processing the tile faster, we do them in chunks of eight. This allows the loop to be
|
|
; unrolled, which means we don't have to keep track of the register value and makes it faster to
|
|
; clear the dirty tile flag after being processed.
|
|
|
|
tdc ; Move to the dedicated direct page for tile rendering
|
|
clc
|
|
adc #$100
|
|
tcd
|
|
|
|
phb ; Save the current bank
|
|
tsc
|
|
sta tmp0 ; Save it on the direct page
|
|
bra at_loop
|
|
|
|
; The DirtyTiles array and the TileStore information is in the Tile Store bank. Because we
|
|
; process up to 8 tiles as a time and the tile code sets the bank register to the target
|
|
; code field bank, we need to restore the bank register each time. So, we pre-push
|
|
; 8 copies of the TileStore bank onto the stack.
|
|
|
|
|
|
at_exit
|
|
tdc ; Move back to the original direct page
|
|
sec
|
|
sbc #$100
|
|
tcd
|
|
|
|
plb ; Restore the original data bank and return
|
|
rts
|
|
dt_base equ $FE ; top of second direct page space
|
|
|
|
at_loop
|
|
lda tmp0
|
|
tcs
|
|
|
|
lda DirtyTileCount ; This is pre-multiplied by 2
|
|
beq at_exit ; If there are no items, exit
|
|
|
|
ldx TileStoreBankDoubled
|
|
phx
|
|
phx
|
|
phx
|
|
|
|
cmp #16 ; If there are >= 8 elements, then
|
|
bcs at_chunk ; do a full chunk
|
|
|
|
stz DirtyTileCount ; Otherwise, this pass will handle them all
|
|
tax
|
|
jmp (at_table,x)
|
|
at_table da at_exit,at_one,at_two,at_three
|
|
da at_four,at_five,at_six,at_seven
|
|
|
|
at_chunk sec
|
|
sbc #16
|
|
sta DirtyTileCount ; Fall through
|
|
|
|
; Because all of the registers get used in the _RenderTile2 subroutine, we
|
|
; push the values from the DirtyTiles array onto the stack and then pop off
|
|
; the values as we go
|
|
|
|
ldy dt_base ; Reload the base index
|
|
ldx DirtyTiles+14,y ; Load the TileStore offset
|
|
stz TileStore+TS_DIRTY,x ; Clear this tile's dirty flag
|
|
jsr _RenderTile2 ; Draw the tile
|
|
plb ; Reset the data bank to the TileStore bank
|
|
|
|
at_seven
|
|
ldy dt_base
|
|
ldx DirtyTiles+12,y
|
|
stz TileStore+TS_DIRTY,x
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
at_six
|
|
ldy dt_base
|
|
ldx DirtyTiles+10,y
|
|
stz TileStore+TS_DIRTY,x
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
at_five
|
|
ldy dt_base
|
|
ldx DirtyTiles+8,y
|
|
stz TileStore+TS_DIRTY,x
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
at_four
|
|
ldy dt_base
|
|
ldx DirtyTiles+6,y
|
|
stz TileStore+TS_DIRTY,x
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
at_three
|
|
ldy dt_base
|
|
ldx DirtyTiles+4,y
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
at_two
|
|
ldy dt_base
|
|
ldx DirtyTiles+2,y
|
|
stz TileStore+TS_DIRTY,x
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
at_one
|
|
ldy dt_base
|
|
ldx DirtyTiles+0,y
|
|
stz TileStore+TS_DIRTY,x
|
|
jsr _RenderTile2
|
|
plb
|
|
|
|
jmp at_loop
|