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

;==================================================================================================
; Handy constants.
const FALSE = 0
const TRUE  = !FALSE

;==================================================================================================
; Fixed memory locations
const raycaster  = $6000   ; main mem
const expandVec  = $800    ; 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 CHAIN_LOADER   = $1E
const FATAL_ERROR    = $1F

;==================================================================================================
; Predefined functions, for circular calls
predef moveBackward

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

;==================================================================================================
; Strings.
byte helloStr[] = "Loading Lawless Legends.\n"
byte initFontStr[] = "Initting font engine.\n"
byte initRaycastStr[] = "Initting raycaster.\n"
byte loopStr[] = "Entering keyboard loop.\n"

;==================================================================================================
; Global variables
word mapNum = 1
word pFont
word pMap
word cmdTbl[64]

; 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
        inx                   ; don't-care return value
        bit setLcRW+lcBank2
        rts
end

;==================================================================================================
; Allocate memory
asm loader  ; (cmd, mainOrAux, amount)
        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

asm initFontEngine ; (pFont)
        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

asm initRaycaster ; (pMap)
        txa
        pha
        bit setROM
        lda evalStkL,x
        ldy evalStkH,x
        jsr $6000
        pla
        tax
        bit setLcRW+lcBank2
        rts
end

asm renderFrame
        txa
        pha
        bit setROM
        jsr $6003
        pla
        tax
        dex                 ; don't-care return value
        bit setLcRW+lcBank2
        rts
end

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

asm setColor
        txa
        pha
        bit setROM
        lda evalStkL,x
        ldy evalStkH,x
        jsr $6009
        bit setLcRW+lcBank2
        pla
        tax
        rts
end

asm goMon
        bit setROM
        jmp $FF69
end

;==================================================================================================
; General methods

def initMap()

  ; 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 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 frame image (and lock it there)
  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 font for the font engine
  pFont = loader(QUEUE_LOAD, MAIN_MEM, 1<<8 | RES_TYPE_FONT)

  ; 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

  ; Start up the font engine
  puts(@initFontStr)
  initFontEngine(pFont)

  ; Start up the raycaster
  puts(@initRaycastStr)
  initRaycaster(pMap)

  ; Set initial player position
  ^playerDir = 1
  *playerX = $280
  *playerY = $380

  ; Draw the first frame
  renderFrame()
end

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

def moveForward()
  word wasBlocked 
  wasBlocked = isBlocked()
  *playerX = *playerX + walkDirs[^playerDir * 2]
  *playerY = *playerY + walkDirs[^playerDir * 2 + 1]
  if !wasBlocked and isBlocked()
    moveBackward()
  fin
end

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

def moveBackward()
  word wasBlocked 
  wasBlocked = isBlocked()
  adjustDir(8)
  moveForward()
  adjustDir(8)
  if !wasBlocked and isBlocked()
    moveForward()
  fin
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 flipToFirstPage
  if ^frontBuf == 1
    renderFrame()
  fin
end

def nextMap()
  flipToFirstPage()
  mapNum = mapNum + 1
  if mapNum > 5
    mapNum = 1
  fin
  initMap()
end

def nextSky()
  skyNum = (skyNum + 1) & $F
  setColor(0<<8 | skyGndTbl1[skyNum])
  setColor(1<<8 | skyGndTbl2[skyNum])
end

def nextGround()
  groundNum = (groundNum + 1) & $F
  setColor(2<<8 | skyGndTbl1[groundNum])
  setColor(3<<8 | skyGndTbl2[groundNum])
end

def kbdLoop()
  word key, func
  while TRUE
    if ^keyboard >= 128
      key = ^keyboard & $7F
      ^keystrobe
      key = key - $20
      if key >= $40
        key = key - $20
      fin
      if key >= 0 and key < $40
        func = cmdTbl[key]
        if func
          func()
          renderFrame()
        fin
      fin
    fin
  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)

initMap()

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

goMon()

done