lawless-legends/Platform/Apple/virtual/src/plasma/gameloop.pla

///////////////////////////////////////////////////////////////////////////////////////////////////
// Handy constants.
const FALSE = 0
const TRUE  = !FALSE
const NULL  = 0

///////////////////////////////////////////////////////////////////////////////////////////////////
// Fixed memory locations
const raycaster  = $6000   // main mem
const expandVec  = $2000   // aux mem
const fontEngine = $BA00   // main mem

///////////////////////////////////////////////////////////////////////////////////////////////////
// Resource numbers
const RES_NUM_RAYCASTER   = 1
const RES_NUM_EXPAND_VEC  = 2
const RES_NUM_FONT_ENGINE = 3

///////////////////////////////////////////////////////////////////////////////////////////////////
// Hardware addresses.
const keyboard  = $C000
const keystrobe = $C010

///////////////////////////////////////////////////////////////////////////////////////////////////
// Memory manager definitions

// Resource types
const RES_TYPE_CODE     = 1
const RES_TYPE_2D_MAP   = 2
const RES_TYPE_3D_MAP   = 3
const RES_TYPE_TILE     = 4
const RES_TYPE_TEXTURE  = 5
const RES_TYPE_SCREEN   = 6
const RES_TYPE_FONT     = 7
const RES_TYPE_MODULE   = 8
const RES_TYPE_BYTECODE = 9
const RES_TYPE_FIXUP    = 10

// Memory banks
const MAIN_MEM = 0
const AUX_MEM  = 1

// Command codes
const RESET_MEMORY   = $10
const REQUEST_MEMORY = $11
const LOCK_MEMORY    = $12
const UNLOCK_MEMORY  = $13
const SET_MEM_TARGET = $14
const START_LOAD     = $15
const QUEUE_LOAD     = $16
const FINISH_LOAD    = $17
const FREE_MEMORY    = $18
const CALC_FREE      = $19
const DEBUG_MEM      = $1A
const CHAIN_LOADER   = $1E
const FATAL_ERROR    = $1F

const callbacks = $300

const OVERMAP = 11

///////////////////////////////////////////////////////////////////////////////////////////////////
// Predefined functions, for circular calls
predef moveBackward, setWindow2

///////////////////////////////////////////////////////////////////////////////////////////////////
// Raycaster variables
word zp = 0
const playerDir = $5D
const playerX   = $5E
const playerY   = $60
const backBuf   = $6A
const frontBuf  = $6B

///////////////////////////////////////////////////////////////////////////////////////////////////
// Font engine variables
const wndleft   = $70  // left edge of the window
const wndwdth   = $71  // right edge (NOT width) of text window
const wndtop    = $72  // top of text window
const wndbtm    = $73  // bottom+1 of text window

const cursh     = $74  // Cursor H-pos 0-39
const cursv     = $75  // Cursor V-pos 0-23

const MAX_LOC_TRIG = 128

///////////////////////////////////////////////////////////////////////////////////////////////////
// Strings.
byte helloStr[] = "Loading Lawless Legends.\n"
byte loopStr[] = "Entering keyboard loop.\n"
byte tooManyTriggers[] = "Too many triggers"

///////////////////////////////////////////////////////////////////////////////////////////////////
// Global variables
byte mapNum = OVERMAP
word pFont
word pMap
word pScripts
word cmdTbl[64]
byte nLocTrig
byte locTrig_x[MAX_LOC_TRIG]
byte locTrig_y[MAX_LOC_TRIG]
word locTrig_func[MAX_LOC_TRIG]
byte prevX
byte prevY
word prevScript
byte prevMapNum
byte redraw
byte titleLoaded = FALSE
byte cacheSky, cacheGround
word cacheX, cacheY
byte cacheDir
byte resetLocFromCache = FALSE

// Movement amounts when walking at each angle
// Each entry consists of an X bump and a Y bump, in 8.8 fixed point
word walkDirs[] = $0040, $0000
word            = $003B, $0018
word            = $002D, $002D
word            = $0018, $003B
word            = $0000, $0040
word            = $FFE8, $003B
word            = $FFD3, $002D
word            = $FFC5, $0018
word            = $FFC0, $0000
word            = $FFC5, $FFE8
word            = $FFD3, $FFD3
word            = $FFE8, $FFC5
word            = $0000, $FFC0
word            = $0018, $FFC5
word            = $002D, $FFD3
word            = $003B, $FFE8

byte skyGndTbl1[] = $00 // lo-bit black
byte              = $00 // lo-bit black
byte              = $00 // lo-bit black
byte              = $02 // violet
byte              = $08 // green
byte              = $0A // lo-bit white
byte              = $0A // lo-bit white
byte              = $0A // lo-bit white
byte              = $20 // hi-bit black
byte              = $20 // hi-bit black
byte              = $20 // hi-bit black
byte              = $22 // blue
byte              = $28 // orange
byte              = $2A // hi-bit white
byte              = $2A // hi-bit white
byte              = $2A // hi-bit white
byte skyGndTbl2[] = $00 // lo-bit black
byte              = $02 // violet
byte              = $08 // green
byte              = $02 // violet
byte              = $08 // green
byte              = $02 // violet
byte              = $08 // green
byte              = $0A // lo-bit white
byte              = $20 // hi-bit black
byte              = $22 // blue
byte              = $28 // orange
byte              = $22 // blue
byte              = $28 // orange
byte              = $22 // blue
byte              = $28 // orange
byte              = $2A // hi-bit white

word skyNum = 9
word groundNum = 10

///////////////////////////////////////////////////////////////////////////////////////////////////
// Definitions used by assembly code
asm __defs
!source "../../include/global.i"
!source "../../include/plasma.i"
!source "../../include/mem.i"
!source "../../include/fontEngine.i"
tmp     = $2
pTmp    = $4
end
        
///////////////////////////////////////////////////////////////////////////////////////////////////
// Print a string
asm puts
        txa
        pha
        bit setROM
        lda evalStkL,x
        sta pTmp
        lda evalStkH,x
        sta pTmp+1
        ldy #0
        lda (pTmp),y
        tax
        iny
-       lda (pTmp),y
        ora #$80
        jsr cout
        iny
        dex
        bne -
        bit setLcRW+lcBank2
        pla
        tax
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Print a 16-bit hex value, followed by a space
asm printHex
        bit setROM
        lda evalStkH,x
        jsr prbyte
        lda evalStkL,x
        jsr prbyte
        lda #$A0
        jsr cout
        bit setLcRW+lcBank2
        rts
end

asm crout
        bit setROM
        jsr crout
        dex                   ; don't-care return value
        bit setLcRW+lcBank2
        rts
end

asm beep
        bit setROM
        jsr bell
        dex                   ; don't-care return value
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Work with the memory manager
// Params: cmd, mainOrAux, amount
asm loader
        txa
        pha
        bit setROM
        lda evalStkL+2,x        ; command code
        pha
        lda evalStkL+1,x        ; main or aux
        lsr
        ldy evalStkH,x          ; address (or other param)
        lda evalStkL,x
        tax
        pla
        bcs +
        jsr mainLoader
        clc
        bcc ++
+       jsr auxLoader
++      stx tmp
        pla
        tax
        inx                     ; drop second and third parameters
        inx
        lda tmp
        sta evalStkL,x
        tya
        sta evalStkH,x
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Set up the font engine
// Params: pFont
asm initFontEngine
        txa
        pha
        bit setROM
        ldy evalStkL,x   ; font engine likes *lo* byte in Y
        lda evalStkH,x   ; hi byte in X
        tax
        jsr setFONT
        ; Set to write text on both hi-res pages at the same time
        lda #pHGR3
        jsr displayMODE
        ; Set to normal (non-inverse) text
        lda #pNORMAL
        jsr drawMODE
        pla
        tax
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Set up the ray casting engine
// Params: pMap
asm initRaycaster
        txa
        pha
        bit setROM
        lda evalStkL,x
        ldy evalStkH,x
        jsr $6000
        pla
        tax
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Render one frame using the ray caster.
// Params: none
asm renderFrame
        txa
        pha
        bit setROM
        jsr $6003
        pla
        tax
        dex                 ; don't-care return value
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Is the player's current position a physical obstruction?
// Params: none
asm isBlocked
        txa
        pha
        bit setROM
        jsr $6006
        tay
        pla
        tax
        dex
        tya
        sta evalStkL,x
        lda #0
        sta evalStkH,x
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Is there a script attached to the player's current position?
// Params: none
asm isScripted
        txa
        pha
        bit setROM
        jsr $6009
        tay
        pla
        tax
        dex
        tya
        sta evalStkL,x
        lda #0
        sta evalStkH,x
        bit setLcRW+lcBank2
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Set either the sky or ground color
// Params: (index<<8) | (colorCode)
asm setColor
        txa
        pha
        bit setROM
        lda evalStkL,x
        ldy evalStkH,x
        jsr $600C
        bit setLcRW+lcBank2
        pla
        tax
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Jump straight to the system monitor
// Params: None
asm goMon
        bit setROM
        jmp $FF69
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Use the font engine to clear the current text window
// Params: None
asm clearWindow
        bit setROM
        txa
        pha
        jsr clearWINDOW
        bit setLcRW+lcBank2
        pla
        tax
        dex                   ; don't-care return value
        rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Display a string using the font engine. Automatically splits lines to keep words from breaking.
// Params: pStr
asm displayStr
    bit setROM
    txa
    pha
    lda evalStkL,x
    sta pTmp
    lda evalStkH,x
    sta pTmp+1
    ldy #0
    lda (pTmp),y
    beq ++
    inc pTmp
    bne +
    inc pTmp+1
+
--  tax
    ldy #0
-   lda (pTmp),y
    cmp #$20
    bcc +
    cmp #$80
    bcc ++
+   lda #$C4
    jsr $fded
    brk
++  dex
    cmp #$20
    beq +
    sta $281,y
    iny
    cpx #0    
    bne -
+   sty $280
    tya
    sec
    adc pTmp
    sta pTmp
    bcc +
    inc pTmp+1
+   txa
    pha
    tya
    clc
    adc cursh
    sec
    sbc #2
    cmp wndwdth
    bcc +
    lda #$D
    jsr printCHAR
+   ldy #$80
    ldx #2
    jsr printSTR
    lda cursh
    cmp wndleft
    beq +
    lda #$20
    jsr printCHAR
+   pla
    bne --
++  lda #$d
    jsr printCHAR
    bit setLcRW+lcBank2
    pla
    tax
    rts
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// General methods

def fatal(msg)
  loader(FATAL_ERROR, MAIN_MEM, msg)
end

def getUpperKey()
  byte key
  while ^keyboard < 128
  loop
  key = ^keyboard & $7F
  ^keystrobe
  if key >= $60
    key = key - $20
  fin
  return key
end

def setSky(num)
  skyNum = num
  setColor(0<<8 | skyGndTbl1[skyNum])
  setColor(1<<8 | skyGndTbl2[skyNum])
end

def nextSky()
  setSky((skyNum + 1) & $F)
end

def setGround(num)
  groundNum = num
  setColor(2<<8 | skyGndTbl1[groundNum])
  setColor(3<<8 | skyGndTbl2[groundNum])
end

def nextGround()
  setGround((groundNum + 1) & $F)
end

def debugMem(bank, code)
  ^$c051
  ^$c054
  printHex(code)
  loader(DEBUG_MEM, bank, 0)
  getUpperKey()
  ^$c050
end

def initMap()
  word scriptModule

  // Reset memory (our module will stay since memory manager locked it upon load)
  loader(RESET_MEMORY, MAIN_MEM, 0)

  // Load the font engine
  loader(SET_MEM_TARGET, MAIN_MEM, fontEngine)
  loader(QUEUE_LOAD,     MAIN_MEM, RES_NUM_FONT_ENGINE<<8 | RES_TYPE_CODE)

  // Load the font for the font engine
  loader(SET_MEM_TARGET, MAIN_MEM, $9000)
  pFont = loader(QUEUE_LOAD, MAIN_MEM, 1<<8 | RES_TYPE_FONT)

  // Load the raycaster
  loader(SET_MEM_TARGET, MAIN_MEM, raycaster)
  loader(QUEUE_LOAD,     MAIN_MEM, RES_NUM_RAYCASTER<<8 | RES_TYPE_CODE)

  // Load the texture expansion code
  loader(SET_MEM_TARGET, AUX_MEM, expandVec)
  loader(QUEUE_LOAD,     AUX_MEM, RES_NUM_EXPAND_VEC<<8 | RES_TYPE_CODE)

  // Load the map
  pMap = loader(QUEUE_LOAD, MAIN_MEM, mapNum<<8 | RES_TYPE_3D_MAP)

  // Load everything that we just queued
  loader(FINISH_LOAD, MAIN_MEM, 1) // 1 = keep open

  // Load the frame image (and lock it there)
  if titleLoaded
    loader(UNLOCK_MEMORY,MAIN_MEM, $2000)
    loader(FREE_MEMORY,  MAIN_MEM, $2000)
    titleLoaded = FALSE
  fin
  loader(SET_MEM_TARGET, MAIN_MEM, $2000)
  loader(QUEUE_LOAD,     MAIN_MEM, 1<<8 | RES_TYPE_SCREEN)
  loader(LOCK_MEMORY,    MAIN_MEM, $2000)

  // Load the scripts for this map, if it has any.
  scriptModule = pMap->2  // first 2 bytes are width and height, third byte is script module num
  if scriptModule
    pScripts = loader(QUEUE_LOAD, MAIN_MEM, (scriptModule << 8) | RES_TYPE_MODULE)
  fin
  loader(FINISH_LOAD, MAIN_MEM, 0) // 1 = keep open, for loading textures

  // Start up the font engine
  initFontEngine(pFont)

  // Start up the raycaster
  initRaycaster(pMap)

  // Set initial player position in case the init script doesn't do it
  ^playerDir = 1
  *playerX = $280
  *playerY = $380

  // Initialize the map scripts
  setWindow2()
  clearWindow()

  prevX = -1
  prevY = -1
  prevScript = -1
  nLocTrig = 0
  prevMapNum = mapNum
  if pScripts
    *pScripts()
  fin

  // If we're returning to a map, resume from where the player left off
  if resetLocFromCache
    *playerX = cacheX
    *playerY = cacheY
    ^playerDir = cacheDir
    prevX = playerX.1 - 1
    prevY = playerY.1 - 1
    setSky(cacheSky)
    setGround(cacheGround)
    resetLocFromCache = FALSE
  fin
  
  // Draw the first frame
  renderFrame()
  redraw = FALSE
end

// Window for the map name bar
def setWindow1()
  ^wndtop = 1
  ^wndbtm = 2
  ^wndleft = 4
  ^wndwdth = 18
  ^cursv = ^wndtop
  ^cursh = ^wndleft
end

// Window for the large upper right bar
def setWindow2()
  ^wndtop = 3
  ^wndbtm = 17
  ^wndleft = 22
  ^wndwdth = 37
  ^cursv = ^wndtop
  ^cursh = ^wndleft
end

// Window for the mid-size lower right bar
def setWindow3()
  ^wndtop = 18
  ^wndbtm = 23
  ^wndleft = 23
  ^wndwdth = 37
  ^cursv = ^wndtop
  ^cursh = ^wndleft
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Actions
def initCmd(key, func)
  if key >= $60
    key = key - $20
  fin
  cmdTbl[key-$20] = func
end

def flipToFirstPage
  if ^frontBuf == 1
    renderFrame()
    redraw = FALSE
  fin
end

def checkScript()
  word x
  word y
  word i
  word func
  x = playerX.1 - 1
  y = playerY.1 - 1
  if x <> prevX or y <> prevY
    prevX = x
    prevY = y
    if prevScript
      clearWindow()
    fin
    prevScript = NULL
    if isScripted()
      for i = 0 to nLocTrig-1
        if x == locTrig_x[i] and y == locTrig_y[i]
          prevScript = locTrig_func[i]
          *prevScript()
        fin
      next
    fin
  fin
  if mapNum <> prevMapNum
    flipToFirstPage()
    initMap()
  fin
end

def moveForward()
  word wasBlocked 
  word func
  wasBlocked = isBlocked()
  *playerX = *playerX + walkDirs[^playerDir << 1]
  *playerY = *playerY + walkDirs[(^playerDir << 1) + 1]
  if !wasBlocked and isBlocked()
    moveBackward()
  fin
end

def adjustDir(n)
  ^playerDir = (^playerDir + n) & $F
end

def moveBackward()
  adjustDir(8)
  moveForward()
  adjustDir(8)
end

def rotateLeft()
  adjustDir(-1)
end

def rotateRight()
  adjustDir(1)
end

def strafeRight()
  adjustDir(4)
  moveForward()
  adjustDir(-4)
end

def strafeLeft()
  adjustDir(-4)
  moveForward()
  adjustDir(4)
end

def setMap(is3d, num)
  // save player state if we're coming *from* the over-map
  if mapNum == OVERMAP
    cacheX = *playerX
    cacheY = *playerY
    cacheDir = ^playerDir
    cacheSky = skyNum
    cacheGround = groundNum
  else
    resetLocFromCache = TRUE
  fin
  mapNum = num
end

def nextMap()
  mapNum = mapNum + 1
  if mapNum > 20
    mapNum = 1
  fin
  setMap(1, mapNum)
end

def teleport(x, y, dir)
  *playerX = ((x+1)<<8) | $80
  *playerY = ((y+1)<<8) | $80
  prevX = x
  prevY = y
  prevScript = -1
  clearWindow()
  ^playerDir = dir
  redraw = TRUE
end

def kbdLoop()
  word key, func
  while TRUE
    key = getUpperKey()
    key = key - $20
    if key >= 0 and key < $40
      func = cmdTbl[key]
      if func
        func()
        renderFrame()
        redraw = FALSE
        checkScript()
        if redraw
          renderFrame()
          redraw = FALSE
        fin
      fin
    fin
  loop
end

def setLocationTrigger(x, y, func)
  if nLocTrig == MAX_LOC_TRIG
    fatal(@tooManyTriggers)
  fin
  locTrig_x[nLocTrig] = x
  locTrig_y[nLocTrig] = y
  locTrig_func[nLocTrig] = func
  nLocTrig = nLocTrig + 1
end

def getYN()
  byte key
  while TRUE
    key = getUpperKey()
    if key == 'Y'
      return 1
    elsif key == 'N'
      clearWindow()
      return 0
    fin
    beep()
  loop
end

///////////////////////////////////////////////////////////////////////////////////////////////////
// Main code.
//
puts(@helloStr)

// Init the command table
initCmd('W', @moveForward)
initCmd('A', @rotateLeft)
initCmd('D', @rotateRight)
initCmd('S', @moveBackward)
initCmd('X', @moveBackward)
initCmd('Z', @strafeLeft)
initCmd('C', @strafeRight)

initCmd('I', @moveForward)
initCmd('J', @rotateLeft)
initCmd('L', @rotateRight)
initCmd('K', @moveBackward)
initCmd(',', @moveBackward)
initCmd('M', @strafeLeft)
initCmd('.', @strafeRight)

initCmd('N', @nextMap)

initCmd('Y', @nextSky)
initCmd('G', @nextGround)

// $300
callbacks.0 = $4c
callbacks:1 = @setLocationTrigger

// $303
callbacks.3 = $4c
callbacks:4 = @displayStr

// $306
callbacks.6 = $4c
callbacks:7 = @getYN

// $309
callbacks.9 = $4c
callbacks:10 = @setMap

// $30C
callbacks.12 = $4c
callbacks:13 = @setSky

// $30F
callbacks.15 = $4c
callbacks:16 = @setGround

// $312
callbacks.18 = $4c
callbacks:19 = @teleport

// Load the title screen
loader(SET_MEM_TARGET, MAIN_MEM, $2000)
loader(QUEUE_LOAD,     MAIN_MEM, 2<<8 | RES_TYPE_SCREEN)
loader(LOCK_MEMORY,    MAIN_MEM, $2000)
loader(FINISH_LOAD, MAIN_MEM, 1) // 1 = keep open
titleLoaded = TRUE
^$c050
^$c057
^$c054
^$c052
// Hack for real (not emulated) IIc: sometimes displays only lo-bit graphics
// unless we do this. *HUGE* thanks to Brendan Robert for the fix!
^$C07E=0   // disable double-hi-res
^$C05F     // disable double-hi-res

initMap()

setWindow2()

// Main keyboard loop
puts(@loopStr)
kbdLoop()

done