Apple-2gs-SW/iigs-game-engine
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iigs-game-engine/src/CoreImpl.s

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Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
; Feature flags
Make the test demo more sophisticated; multiple sprites
2022-06-02 03:24:45 +00:00
NO_INTERRUPTS equ 0 ; turn off for crossrunner debugging
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
NO_MUSIC equ 1 ; turn music + tool loading off
; External data space provided by the main program segment
tiledata EXT
TileStore EXT
; Sprite plane data and mask banks are provided as an external segment
;
; The sprite data holds a set of pre-rendered sprites that are optimized to support the rendering pipeline. There
; are four copies of each sprite, along with the cooresponding mask laid out into 4x4 tile regions where the
; empty row and column is shared between adjacent blocks.
;
; Logically, the memory is laid out as 4 columns of sprites and 4 rows.
;
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | | | | | | | | | | | | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | 0 | 0 | | 1 | 1 | | 2 | 2 | | 3 | 3 | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | 0 | 0 | | 1 | 1 | | 2 | 2 | | 3 | 3 | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | | | | | | | | | | | | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | 4 | 4 | | 5 | 5 | | 6 | 6 | | 7 | 7 | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | 4 | 4 | | 5 | 5 | | 6 | 6 | | 7 | 7 | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
; | | | | | | | | | | | | | ...
; +---+---+---+---+---+---+---+---+---+---+---+---+-...
;
; For each sprite, when it needs to be copied into an on-screen tile, it could exist at any offset compared to its
; natural alignment. By having a buffer around the sprite data, an address pointer can be set to a different origin
; and a simple 8x8 block copy can cut out the appropriate bit of the sprite. For example, here is a zoomed-in look
; at a sprite with an offset, O, at (-2,-3). As shown, by selecting an appropriate origin, just the top corner
; of the sprite data will be copied.
;
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; | | || | || | | | || | | | |
; +---+-- O----------------+ --+---++---+---+---+---++---+---+---+---+..
; | | | | | || | | | || | | | |
; +---+-- | | --+---++---+---+---+---++---+---+---+---+..
; | | | | | || | | | || | | | |
; +---+-- | | --+---++---+---+---+---++---+---+---+---+..
; | | | | | || | | | || | | | |
; +===+== | ++===+== | ==+===++===+===+===+===++===+===+===+===+..
; | | | || | S | S | S || S | S | S | || | | | |
; +---+-- +----------------+ --+---++---+---+---+---++---+---+---+---+..
; | | || S | S S | S || S | S | S | S || | | | |
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; | | | | || S | S | S | S || S | S | S | S || | | | |
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; | | | | || S | S | S | S || S | S | S | S || | | | |
; +===+===+===+===++===+===+===+===++===+===+===+===++===+===+===+===+..
; | | | | || S | S | S | S || S | S | S | S || | | | |
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; | | | | || S | S | S | S || S | S | S | S || | | | |
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; | | | | || S | S | S | S || S | S | S | S || | | | |
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; | | | | || | S | S | S || S | S | S | || | | | |
; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
; . . . . . . . . . . . . . . . . .
;
; Each sprite will take up, effectively 9 tiles of storage space per
; instance (plus edges) and there are 4 instances for the H/V bits
; and 4 more for the masks. This results in a need for 43,264 bytes
; for all 16 sprites.
spritedata EXT
spritemask EXT
; Core engine functionality. The idea is that that source file can be PUT into
; a main source file and all of the functionality will be available.
;
; There are some constancts that must be externally defined that can affect how
; the GTE runtime works
;
; NO_MUSIC : Set to non-zero to avoid using any source
; NO_INTERRUPTS : Set to non-zero to avoid installing custom interrupt handlers
mx %00
Basic working user tool framework
2022-04-24 19:45:07 +00:00
; Assumes the direct page is set and EngineMode and UserId has been initialized
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
_CoreStartUp
Complete initialization sequence.
2022-04-25 21:35:47 +00:00
jsr IntStartUp ; Enable certain interrupts
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
Complete initialization sequence.
2022-04-25 21:35:47 +00:00
jsr InitMemory ; Allocate and initialize memory for the engine
jsr EngineReset ; All of the resources are allocated, put the engine in a known state
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
Complete initialization sequence.
2022-04-25 21:35:47 +00:00
jsr InitGraphics ; Initialize all of the graphics-related data
Another checkpoint; converging on the working implementation
2022-05-31 13:43:26 +00:00
jsr InitSprites ; Initialize the sprite subsystem
Complete initialization sequence.
2022-04-25 21:35:47 +00:00
jsr InitTiles ; Initialize the tile subsystem
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
Complete initialization sequence.
2022-04-25 21:35:47 +00:00
jsr InitTimers ; Initialize the timer subsystem
Break up large source code files to help with dependency ordering
2022-04-25 16:32:06 +00:00
rts
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
_CoreShutDown
jsr IntShutDown
rts
; Install interrupt handlers. We use the VBL interrupt to keep animations
; moving at a consistent rate, regarless of the rendered frame rate. The
; one-second timer is generally just used for counters and as a handy
; frames-per-second trigger.
IntStartUp
lda #NO_INTERRUPTS
bne :no_interrupts
PushLong #0
pea $0015 ; Get the existing 1-second interrupt handler and save
_GetVector
PullLong OldOneSecVec
pea $0015 ; Set the new handler and enable interrupts
PushLong #OneSecHandler
_SetVector
pea $0006
_IntSource
PushLong #VBLTASK ; Also register a Heart Beat Task
_SetHeartBeat
:no_interrupts
rts
IntShutDown
lda #NO_INTERRUPTS
bne :no_interrupts
pea $0007 ; disable 1-second interrupts
_IntSource
PushLong #VBLTASK ; Remove our heartbeat task
_DelHeartBeat
pea $0015
PushLong OldOneSecVec ; Reset the interrupt vector
_SetVector
:no_interrupts
rts
; Interrupt handlers. We install a heartbeat (1/60th second and a 1-second timer)
OneSecHandler mx %11
phb
pha
Move most data storage to separate bank; fix many banking bugs
2022-05-19 02:00:06 +00:00
jsr _SetDataBank
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
rep #$20
inc OneSecondCounter
sep #$20
ldal $E0C032
and #%10111111 ;clear IRQ source
stal $E0C032
pla
plb
clc
rtl
mx %00
Move most data storage to separate bank; fix many banking bugs
2022-05-19 02:00:06 +00:00
; This is OK, it's referenced by a long address
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
VBLTASK hex 00000000
dw 0
hex 5AA5
; Reset the engine to a known state
; Blitter initialization
EngineReset
stz ScreenHeight
stz ScreenWidth
stz ScreenY0
stz ScreenY1
stz ScreenX0
stz ScreenX1
stz ScreenTileHeight
stz ScreenTileWidth
stz StartX
stz OldStartX
stz StartXMod164
stz StartY
stz OldStartY
stz StartYMod208
Basic working user tool framework
2022-04-24 19:45:07 +00:00
; stz EngineMode
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
stz DirtyBits
Add a full complement of firty tile rendering functions
2022-07-06 04:48:33 +00:00
stz LastRender ; Initialize as is a full render was performed
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
stz LastPatchOffset
stz BG1StartX
stz BG1StartXMod164
stz BG1StartY
stz BG1StartYMod208
stz BG1OffsetIndex
stz BG0TileOriginX
stz BG0TileOriginY
stz OldBG0TileOriginX
stz OldBG0TileOriginY
stz BG1TileOriginX
stz BG1TileOriginY
stz OldBG1TileOriginX
stz OldBG1TileOriginY
stz TileMapWidth
stz TileMapHeight
stz TileMapPtr
stz TileMapPtr+2
stz FringeMapPtr
stz FringeMapPtr+2
stz BG1TileMapWidth
stz BG1TileMapHeight
stz BG1TileMapPtr
stz BG1TileMapPtr+2
stz SCBArrayPtr
stz SCBArrayPtr+2
stz SpriteBanks
stz SpriteMap
stz ActiveSpriteCount
stz OneSecondCounter
lda #13
sta tmp15
stz tmp14
Checkpoint; blitter failing
2022-08-14 12:45:58 +00:00
; Rebuild all of the bank blitters
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
:loop
ldx #BlitBuff
lda #^BlitBuff
ldy tmp14
Complete initialization sequence.
2022-04-25 21:35:47 +00:00
jsr BuildBank
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
lda tmp14
clc
adc #4
sta tmp14
dec tmp15
bne :loop
Checkpoint; blitter failing
2022-08-14 12:45:58 +00:00
; Set the scanline tables to reasonable default values
ldx #{416*2}-2
lda #0
:sxm_loop
sta StartXMod164Arr,x
dex
dex
bpl :sxm_loop
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
rts
WaitForKey sep #$20
stal KBD_STROBE_REG ; clear the strobe
:WFK ldal KBD_REG
bpl :WFK
rep #$20
and #$007F
rts
ClearKbdStrobe sep #$20
stal KBD_STROBE_REG
rep #$20
rts
; Read the keyboard and paddle controls and return in a game-controller-like format
Make the test demo more sophisticated; multiple sprites
2022-06-02 03:24:45 +00:00
_ReadControl pea $0000 ; low byte = key code, high byte = %------AB
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
sep #$20
ldal OPTION_KEY_REG ; 'B' button
and #$80
beq :BNotDown
Set dirty render to the correct direct page and several small cleanups
2022-07-06 19:55:27 +00:00
lda #>PAD_BUTTON_B
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
ora 2,s
sta 2,s
:BNotDown
ldal COMMAND_KEY_REG
and #$80
beq :ANotDown
Set dirty render to the correct direct page and several small cleanups
2022-07-06 19:55:27 +00:00
lda #>PAD_BUTTON_A
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
ora 2,s
sta 2,s
:ANotDown
ldal KBD_STROBE_REG ; read the keyboard
bit #$80
beq :KbdNotDwn ; check the key-down status
and #$7f
ora 1,s
sta 1,s
More banking fixes
2022-05-20 04:40:45 +00:00
cmp LastKey
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
beq :KbdDown
More banking fixes
2022-05-20 04:40:45 +00:00
sta LastKey
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
Set dirty render to the correct direct page and several small cleanups
2022-07-06 19:55:27 +00:00
lda #>PAD_KEY_DOWN ; set the keydown flag
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
ora 2,s
sta 2,s
bra :KbdDown
:KbdNotDwn
More banking fixes
2022-05-20 04:40:45 +00:00
stz LastKey
Refactor to support building a tool and new demo to try and use it [not working]
2022-04-23 05:47:13 +00:00
:KbdDown
rep #$20
pla
rts
; Helper function to take a local pixel coordinate [0, ScreenWidth-1],[0, ScreenHeight-1] and return the
; row and column in the tile store that is corresponds to. This takes into consideration the StartX and
; StartY offsets.
;
; This is more specialized than the code in the _MarkDirtySprite routine below since it does not deal with
; negative or off-screen values.
_OriginToTileStore
lda StartYMod208
lsr
lsr
and #$FFFE ; Store the pre-multiplied by 2 for indexing
tay
lda StartXMod164
lsr
and #$FFFE ; Same pre-multiply by 2 for later
tax
rts
; X = local x-coordinate (0, playfield width)
; Y = local y-coordinate (0, playfield height)
_LocalToTileStore
clc
tya
adc StartYMod208 ; Adjust for the scroll offset
cmp #208 ; check if we went too far positive
bcc *+5
sbc #208
lsr
lsr
and #$FFFE ; Store the pre-multiplied by 2 for indexing
tay
clc
txa
adc StartXMod164
cmp #164
bcc *+5
sbc #164
lsr
and #$FFFE ; Same pre-multiply by 2 for later
tax
rts
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