raze-gles/polymer/eduke32/source/lunatic/defs.ilua

-- definitions of BUILD and game types for the Lunatic Interpreter
-- INTERNAL!

local ffi = require("ffi")

---- sector, wall, sprite ----
ffi.cdef[[
#pragma pack(push,1)
typedef struct
{
    const int16_t wallptr, wallnum;
    int32_t ceilingz, floorz;
    int16_t ceilingstat, floorstat;
    int16_t ceilingpicnum, ceilingheinum;
    int8_t ceilingshade;
    uint8_t ceilingpal, ceilingxpanning, ceilingypanning;
    int16_t floorpicnum, floorheinum;
    int8_t floorshade;
    uint8_t floorpal, floorxpanning, floorypanning;
    uint8_t visibility, filler;
    int16_t lotag, hitag, extra;
} sectortype;

typedef struct
{
    int32_t x, y;
    const int16_t point2, nextwall, nextsector; int16_t cstat;
    int16_t picnum, overpicnum;
    int8_t shade;
    uint8_t pal, xrepeat, yrepeat, xpanning, ypanning;
    int16_t lotag, hitag, extra;
} walltype;

typedef struct
{
    int32_t x, y, z;
    int16_t cstat, picnum;
    int8_t shade;
    uint8_t pal, clipdist, filler;
    uint8_t xrepeat, yrepeat;
    int8_t xoffset, yoffset;
    int16_t sectnum, statnum;
    int16_t ang, owner, xvel, yvel, zvel;
    int16_t lotag, hitag, extra;
} spritetype;
#pragma pack(pop)
]]

ffi.cdef[[
sectortype *sector;
walltype *wall;
spritetype *sprite;

const int16_t numsectors, numwalls;

const int16_t headspritesect[16384+1], headspritestat[1024+1];
const int16_t prevspritesect[16384], prevspritestat[16384];
const int16_t nextspritesect[16384], nextspritestat[16384];
]]

--

---- Set up restricted access to ffi.C from lunatic. ----
local ffiC = ffi.C

local det = {}  -- dummy empty table
local tmpmt = {
    __index = function() error('dummy variable: read access forbidden') end,
    __newindex = function() error('dummy variable: write access forbidden') end,
    __metatable = true  -- forbid setting the metatable
}
setmetatable(det, tmpmt)

-- GLOBAL gv: provides access to C global *scalars*
gv = {
    -- all non-scalars need to be explicitly listed
    -- and access to them is redirected to the dummy
    -- empty table... this is somewhat ugly
    sector = det,
    wall = det,
    sprite = det,

    headspritesect = det, headspritestat = det,
    prevspritesect = det, prevspritestat = det,
    nextspritesect = det, nextspritestat = det,
}
local tmpmt = {
    __index = ffiC,
    __newindex = function() error("cannot create new fields in 'gv'") end,
    __metatable = true,
}
setmetatable(gv, tmpmt)

---- indirect C array access ----
sector = {}
local tmpmt = {
    __index = function(tab, key)
                  if (key >= 0 and key < ffiC.numsectors) then return ffiC.sector[key] end
                  error('out-of-bounds sector[] read access')
              end,

    __newindex = function(tab, key, val) error('cannot write to sector[] struct directly') end,
    __metatable = true,
}
setmetatable(sector, tmpmt)

wall = {}
local tmpmt = {
    __index = function(tab, key)
                  if (key >= 0 and key < ffiC.numwalls) then return ffiC.wall[key] end
                  error('out-of-bounds wall[] read access')
              end,

    __newindex = function(tab, key, val) error('cannot write to wall[] struct directly') end,
    __metatable = true,
}
setmetatable(wall, tmpmt)

-- create a safe indirection for a ffi.C array
local function creategtab(ctab, maxidx, name)
    local tab = {}
    local tmpmt = {
        __index = function(tab, key)
                      if (key>=0 and key < maxidx) then
                          return ctab[key]
                      end
                      error('out-of-bounds '..name..' read access')
                  end,
        __newindex = function(tab, key, val)
                         error('cannot write to '..name)
                     end,
        __metatable = true,
    }
    setmetatable(tab, tmpmt)
    return tab
end

sprite = creategtab(ffiC.sprite, 16384, 'sprite[] struct')
headspritesect = creategtab(ffiC.headspritesect, 16384, 'headspritesect[]')
headspritestat = creategtab(ffiC.headspritestat, 1024, 'headspritestat[]')
nextspritesect = creategtab(ffiC.nextspritesect, 16384, 'nextspritesect[]')
nextspritestat = creategtab(ffiC.nextspritestat, 16384, 'nextspritestat[]')
prevspritesect = creategtab(ffiC.prevspritesect, 16384, 'prevspritesect[]')
prevspritestat = creategtab(ffiC.prevspritestat, 16384, 'prevspritestat[]')

---- per-sector/per-statnum sprite iterators ----
local function iter_spritesofsect(sect, i)
    if (i < 0) then
        i = ffiC.headspritesect[sect]
    else
        i = ffiC.nextspritesect[i]
    end

    if (i >= 0) then return i, i end
end

function spritesofsect(sect)
    assert(sect >= 0 and sect < ffiC.numsectors, "passed invalid sectnum to spritesofsect iterator")

    return iter_spritesofsect, sect, -1
end

local function iter_spritesofstat(stat, i)
    if (i < 0) then
        i = ffiC.headspritestat[stat]
    else
        i = ffiC.nextspritestat[i]
    end

    if (i >= 0) then return i, i end
end

function spritesofstat(stat)
    assert(stat >= 0 and stat < 1024, "passed invalid statnum to spritesofstat iterator")

    return iter_spritesofstat , stat, -1
end

-- restrict access to potentially unsafe standard Lua modules (not yet done)
os = nil
io = nil