135 lines
7.1 KiB
ArmAsm
135 lines
7.1 KiB
ArmAsm
; Tile storage parameters
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TILE_DATA_SPAN equ 4
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TILE_STORE_WIDTH equ 41
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TILE_STORE_HEIGHT equ 26
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MAX_TILES equ {26*41} ; Number of tiles in the code field (41 columns * 26 rows)
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TILE_STORE_SIZE equ {MAX_TILES*2} ; The tile store contains a tile descriptor in each slot
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TS_TILE_ID equ {TILE_STORE_SIZE*0} ; tile descriptor for this location
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TS_DIRTY equ {TILE_STORE_SIZE*1} ; Flag. Used to prevent a tile from being queued multiple times per frame
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TS_SPRITE_FLAG equ {TILE_STORE_SIZE*2} ; Bitfield of all sprites that intersect this tile. 0 if no sprites.
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TS_TILE_ADDR equ {TILE_STORE_SIZE*3} ; cached value, the address of the tiledata for this tile
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TS_CODE_ADDR_LOW equ {TILE_STORE_SIZE*4} ; const value, address of this tile in the code fields
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TS_CODE_ADDR_HIGH equ {TILE_STORE_SIZE*5}
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TS_WORD_OFFSET equ {TILE_STORE_SIZE*6} ; const value, word offset value for this tile if LDA (dp),y instructions re used
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TS_JMP_ADDR equ {TILE_STORE_SIZE*7} ; const value, address of the 32-byte snippet space for this tile
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TS_SCREEN_ADDR equ {TILE_STORE_SIZE*8} ; cached value of on-screen location of tile. Used for DirtyRender.
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; TODO: Move these arrays into the K bank to support direct dispatch via jmp (abs,x)
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; TS_BASE_TILE_COPY equ {TILE_STORE_SIZE*9} ; derived from TS_TILE_ID to optimize tile copy to support sprite rendering
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; TS_BASE_TILE_DISP equ {TILE_STORE_SIZE*10} ; derived from TS_TILE_ID to optimize base (non-sprite) tile dispatch in the Render function
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; TS_DIRTY_TILE_DISP equ {TILE_STORE_SIZE*11} ; derived from TS_TILE_ID to optimize dirty tile dispatch in the Render function
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TILE_STORE_NUM equ 12 ; Need this many parallel arrays
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; Sprite data structures. We cache quite a few pieces of information about the sprite
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; to make calculations faster, so this is hidden from the caller.
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MAX_SPRITES equ 16
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SPRITE_REC_SIZE equ 42
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MAX_OVERLAYS equ 2
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MAX_ELEMENTS equ {MAX_SPRITES+MAX_OVERLAYS}
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; Object list used in renderer
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OL_SPRITE_ID equ 0 ; Usual parallel arrays
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OL_SPRITE_TOP equ {2*{MAX_ELEMENTS+1}}
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OL_SPRITE_BOTTOM equ {4*{MAX_ELEMENTS+1}}
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OL_NEXT equ {6*{MAX_ELEMENTS+1}}
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OL_INDEX equ {8*{MAX_ELEMENTS+1}} ; Reference to the index in the _Sprites array
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; Mark each sprite as ADDED, UPDATED, MOVED, REMOVED depending on the actions applied to it
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; on this frame. Quick note, the same Sprite ID cannot be removed and added in the same frame.
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; A REMOVED sprite if removed from the sprite list during the Render call, so it's ID is not
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; available to the AddSprite function until the next frame.
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SPRITE_STATUS_EMPTY equ $0000 ; If the status value is zero, this sprite slot is available
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SPRITE_STATUS_ADDED equ $0001 ; Sprite was just added (new sprite)
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SPRITE_STATUS_MOVED equ $0002 ; Sprite's position was changed
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SPRITE_STATUS_UPDATED equ $0004 ; Sprite's non-position attributes were changed
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SPRITE_STATUS_REMOVED equ $0008 ; Sprite has been removed.
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SPRITE_STATUS_HIDDEN equ $0010 ; Sprite is in a hidden state
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; These values are set by the user
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SPRITE_STATUS equ {MAX_ELEMENTS*0}
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SPRITE_ID equ {MAX_ELEMENTS*2}
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SPRITE_X equ {MAX_ELEMENTS*4}
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SPRITE_Y equ {MAX_ELEMENTS*6}
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VBUFF_ADDR equ {MAX_ELEMENTS*8} ; Base address of the sprite's stamp in the data/mask banks
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; These values are cached / calculated during the rendering process
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TS_LOOKUP_INDEX equ {MAX_ELEMENTS*10} ; The index from the TileStoreLookup table that corresponds to the top-left corner of the sprite
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TS_COVERAGE_SIZE equ {MAX_ELEMENTS*12} ; Representation of how many TileStore tiles (NxM) are covered by this sprite
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SPRITE_DISP equ {MAX_ELEMENTS*14} ; Cached address of the specific stamp based on sprite flags
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SPRITE_CLIP_LEFT equ {MAX_ELEMENTS*16}
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SPRITE_CLIP_RIGHT equ {MAX_ELEMENTS*18}
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SPRITE_CLIP_TOP equ {MAX_ELEMENTS*20}
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SPRITE_CLIP_BOTTOM equ {MAX_ELEMENTS*22}
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IS_OFF_SCREEN equ {MAX_ELEMENTS*24}
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SPRITE_WIDTH equ {MAX_ELEMENTS*26}
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SPRITE_HEIGHT equ {MAX_ELEMENTS*28}
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SPRITE_CLIP_WIDTH equ {MAX_ELEMENTS*30}
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SPRITE_CLIP_HEIGHT equ {MAX_ELEMENTS*32}
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TS_VBUFF_BASE equ {MAX_ELEMENTS*34} ; Finalized VBUFF address based on the sprite position and tile offsets
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SORTED_PREV equ {MAX_ELEMENTS*36} ; Doubly-Linked List that maintains the sprites in sorted order based on SPRITE_Y
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SORTED_NEXT equ {MAX_ELEMENTS*38}
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; The Overlays are part of the _Sprites memory space and come after the maximum number of sprites
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Overlays equ {_Sprites+{MAX_SPRITES*2}}
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; Aliases of SPRITE_* memory locations that are used for Overlay info when the SPRITE_OVERLAY bit is set on SPRITE_ID
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OVERLAY_ID equ SPRITE_ID
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OVERLAY_FLAGS equ SPRITE_STATUS
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OVERLAY_TOP equ SPRITE_CLIP_TOP ; This is important because SPRITE_CLIP_TOP is used for sorting
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OVERLAY_BOTTOM equ SPRITE_CLIP_BOTTOM
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OVERLAY_HEIGHT equ SPRITE_HEIGHT
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OVERLAY_PROC equ VBUFF_ADDR
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; 52 rows by 82 columns + 2 extra rows and columns for sprite sizes
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;
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; 53 rows = TILE_STORE_HEIGHT + TILE_STORE_HEIGHT + 1
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; 83 cols = TILE_STORE_WIDTH + TILE_STORE_WIDTH + 1
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;
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; TILE_STORE_WIDTH equ 41
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; TILE_STORE_HEIGHT equ 26
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TS_LOOKUP_WIDTH equ 82
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TS_LOOKUP_HEIGHT equ 52
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TS_LOOKUP_BORDER equ 2
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TS_LOOKUP_SPAN equ {TS_LOOKUP_WIDTH+TS_LOOKUP_BORDER}
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TS_LOOKUP_ROWS equ {TS_LOOKUP_HEIGHT+TS_LOOKUP_BORDER}
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; Blitter template constants
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PER_TILE_SIZE equ 3
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SNIPPET_SIZE equ 32
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;----------------------------------------------------------------------
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;
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; Timer implementation
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;
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; The engire provides four timer slot that can be used by one-shot or
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; recurring timers. Each timer is given an initial tick count, a
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; reset tick count (0 = one-shot), and an action to perform.
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;
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; The timers handle overflow, so if a recurring timer has a tick count of 3
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; and 7 VBL ticks have passed, then the timer will be fired twice and
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; a tick count of 2 will be set.
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;
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; As such, the timers are appropriate to drive physical and other game
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; behaviors at a frame-independent rate.
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;
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; A collection of 4 timers that are triggered when their countdown
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; goes below zero. Each timer takes up 16 bytes
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;
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; A timer can fire multiple times during a singular evaluation. For example, if the
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; timer delay is set to 1 and 3 VBL ticks happen, then the timer delta is -2, will fire,
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; have the delay added and get -1, fire again, increment to zero, first again and then
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; finally reset to 1.
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;
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; +0 counter decremented by the number of ticks since last run
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; +2 reset copied into counter when triggered. 0 turns off the timer.
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; +4 addr long address of timer routine
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; +8 user 8 bytes of user data space for timer state
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MAX_TIMERS equ 4
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TIMER_REC_SIZE equ 16
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