raze-gles/polymer/eduke32/source/lunatic/control.lua

-- Game control module for Lunatic.

local ffi = require("ffi")
local ffiC = ffi.C

local bit = require("bit")
local math = require("math")

local setmetatable = setmetatable

local error = error
local type = type

local player = assert(player)
local cansee = require("defs_common").cansee


module(...)


local lastid = { action=0, move=0, ai=0 }
local def = { action={}, move={}, ai={} }

local function forbidden() error("newindex forbidden", 2) end

AC = setmetatable({}, { __index=def.action, __newindex=forbidden })
MV = setmetatable({}, { __index=def.move, __newindex=forbidden })
AI = setmetatable({}, { __index=def.ai, __newindex=forbidden })

local function check_name(name, what, errlev)
    if (type(name)~="string" or #name > 63) then
        error("bad argument #1 to "..what..": must be a string of length <= 63", errlev+1)
    end
end

local function action_or_move(what, numargs, tab, name, ...)
    if (lastid[what] <= -(2^31)) then
        error("Too many "..what.."s defined", 3);
    end
    check_name(name, what, 3)

    local args = {...}
    if (#args > numargs) then
        error("Too many arguments passed to "..what, 3)
    end

    for i=1,#args do
        local n = args[i]
        if (type(n)~="number" or not (n >= -32768 and n <= 32767)) then
            error("bad argument #".. i+1 .." to "..what..
                  ": must be numbers in [-32768..32767]", 3)
        end
    end
    -- missing fields are initialized to 0 by ffi.new

    -- Named actions or moves have negative ids so that non-negative ones
    -- can be used as (different) placeholders for all-zero ones.
    lastid[what] = lastid[what]-1

    -- ffi.new takes either for initialization: varargs, a table with numeric
    -- indices, or a table with key-value pairs
    -- See http://luajit.org/ext_ffi_semantics.html#init_table
    tab[name] = ffi.new("const con_"..what.."_t", lastid[what], args)
end

function action(name, ...)
    action_or_move("action", 5, def.action, name, ...)
end

function move(name, ...)
    action_or_move("move", 2, def.move, name, ...)
end


local function get_action_or_move(what, val, argi)
    if (val == nil) then
        return {}  -- will init the struct to all zeros
    elseif (type(val)=="string") then
        local am = def[what][val]
        if (am==nil) then
            error("no "..what.." '"..val.."' defined", 3)
        end
        return am
    elseif (ffi.istype("con_"..what.."_t", val)) then
        return val
    end

    -- TODO: literal number actions/moves?
    error("bad argument #"..argi.." to ai: must be string or "..what, 3)
end

function ai(name, action, move, flags)
    if (lastid.ai <= -(2^31)) then
        error("Too many AIs defined", 2);
    end
    check_name(name, "ai", 2)

    lastid.ai = lastid.ai-1

    local act = get_action_or_move("action", action, 2)
    local mov = get_action_or_move("move", move, 3)

    if (flags~=nil) then
        if (type(flags)~="number" or not (flags>=0 and flags<=32767)) then
            error("bad argument #4 to ai: must be a number in [0..32767]", 2)
        end
    else
        flags = 0
    end

    def.ai[name] = ffi.new("const con_ai_t", lastid.ai, act, mov, flags)
end


---=== RUNTIME CON FUNCTIONS ===---

function rotatesprite(x, y, zoom, ang, tilenum, shade, pal, orientation,
                      cx1, cy1, cx2, cy2)
    if (type(tilenum) ~= "number" or not (tilenum >= 0 and tilenum < ffiC.MAXTILES)) then
        error("bad argument #5 to rotatesprite: must be number in [0.."..ffiC.MAXTILES.."]", 2)
    end

    ffiC.rotatesprite(65536*x, 65536*y, zoom, ang, tilenum, shade, pal, bit.bor(2,orientation),
                      cx1, cy1, cx2, cy2)
end

function rnd(x)
    return (bit.rshift(ffiC.krand(), 8) >= (255-x))
end


---=== Weapon stuff ===---


--- Helper functions (might be exported later) ---

local function have_weapon(ps, weap)
    return (bit.band(ps.gotweapon, bit.lshift(1, weap)) ~= 0)
end

local function have_ammo_at_max(ps, weap)
    return (ps:get_ammo_amount(weap) >= ps:get_max_ammo_amount(weap))
end

local function P_AddAmmo(ps, weap, amount)
    if (not have_ammo_at_max(ps, weap)) then
        -- NOTE: no clamping towards the bottom
        ps:set_ammo_amount(weap, math.min(curamount+amount, maxamount))
    end
end

local function P_AddWeaponAmmoCommon(ps, weap, amount)
    P_AddAmmo(ps, weap, amount)

    if (ps.curr_weapon==KNEE_WEAPON and have_weapon(weap)) then
        ffiC.P_AddWeaponMaybeSwitch(ps, weap);
    end
end


--- Functions that must be exported because they are used by LunaCON generated code,
--- but which are off limits to users.  (That is, we need to think about how to
--- expose the functionality in a better fashion than merely giving access to
--- the C functions.)

local function check_sprite_idx(i)
    if (i >= ffiC.MAXSPRITES+0ULL) then
        error("invalid argument: must be a valid sprite index", 3)
    end
end

local function check_tile_idx(tilenum)
    if (tilenum >= ffiC.MAXTILES+0ULL) then
        error("invalid argument: must be a valid tile number", 3)
    end
end

function _A_Shoot(i, atwith)
    check_sprite_idx(i)
    check_tile_idx(atwith)

    return ffiC.A_Shoot(i, atwith)
end

function _A_IncurDamage(sn)
    check_sprite_idx(sn)
    return ffiC.A_IncurDamage(sn)
end

function _VM_FallSprite(i)
    check_sprite_idx(i)
    ffiC.VM_FallSprite(i)
end

function _sizeto(i, xr, yr)
    local spr = sprite[i]
    local dr = (xr-spr.xrepeat)
    -- NOTE: could "overflow" (e.g. goal repeat is 256, gets converted to 0)
    spr.xrepeat = spr.xrepeat + ((dr == 0) and 0 or (dr < 0 and -1 or 1))
    -- TODO: y stretching is conditional
    dr = (yr-spr.yrepeat)
    spr.yrepeat = spr.yrepeat + ((dr == 0) and 0 or (dr < 0 and -1 or 1))
end

-- NOTE: function args have overloaded meaning
function _A_Spawn(j, pn)
    local bound_check = sector[sprite[j].sectnum]  -- two in one whack
    check_tile_idx(pn)
    return ffiC.A_Spawn(j, pn)
end

function _pstomp(ps, i)
    if (ps.knee_incs == 0 and sprite[ps.i].xrepeat >= 40) then
        local spr = sprite[i]
        if (cansee(spr^(4*256), spr.sectnum, ps.pos^(-16*256), sprite[ps.i].sectnum)) then
            for j=ffiC.playerswhenstarted-1,0 do
                if (player[j].actorsqu == i) then
                    return
                end
            end
            ps.actorsqu = i
            ps.knee_incs = -1
            if (ps.weapon_pos == 0) then
                ps.weapon_pos = -1
            end
        end
    end
end

function _VM_ResetPlayer2(snum)
    local bound_check = player[snum]
    return (ffiC.VM_ResetPlayer2(snum)~=0)
end

function _addinventory(p, inv, amount, pal)
    if (inv == ffiC.GET_ACCESS) then
        local PALBITS = { [0]=1, [21]=2, [23]=4 }
        if (PALBITS[pal]) then
            ps.got_access = bit.bor(ps.got_access, PALBITS[pal])
        end
    else
        local ICONS = {
            [ffiC.GET_FIRSTAID] = 1,  -- ICON_FIRSTAID
            [ffiC.GET_STEROIDS] = 2,
            [ffiC.GET_HOLODUKE] = 3,
            [ffiC.GET_JETPACK] = 4,
            [ffiC.GET_HEATS] = 5,
            [ffiC.GET_SCUBA] = 6,
            [ffiC.GET_BOOTS] = 7,
        }

        if (ICONS[inv]) then
            ps.inven_icon = ICONS[inv]
        end

        if (inv == ffiC.GET_SHIELD) then
            amount = math.min(ps.max_shield_amount, amount)
        end
        -- NOTE: this is more permissive than CON, e.g. allows
        -- GET_DUMMY1 too.
        ps:set_inv_amount(inv, amount)
    end
end

-- The return value is true iff the ammo was at the weapon's max.
-- In that case, no action is taken.
function _addammo(ps, weapon, amount)
    return have_ammo_at_max(ps, weap) or P_AddWeaponAmmoCommon(ps, weap, amount)
end

function _addweapon(ps, weapon, amount)
    if (weap >= ffiC.MAX_WEAPONS+0ULL) then
        error("Invalid weapon ID "..weap, 2)
    end

    if (not have_weapon(ps, weap)) then
        ffiC.P_AddWeaponMaybeSwitch(ps, weap);
    elseif (have_ammo_at_max(ps, weap)) then
        return true
    end

    P_AddWeaponAmmoCommon(ps, weap, amount)
end


--- Exported functions ---

-- Non-local control flow. These ones call the original error(), not our
-- redefinition in defs.ilua.
function longjmp()
    error(false)
end

function killit()
    -- TODO: guard against deletion of player sprite?
    error(true)
end