pam.lua

-- Polygonal Animated Model library
-- by Xytabich
-- types 0-31 is reserved, please, don't use their

local fs = require("filesystem")

local function grab_byte(v)
      return math.floor(v / 256), string.char(math.floor(v) % 256)
end

pam = {}

pam.float2str = function(x)
   local sign = 0
   if x < 0 then
     sign = 1
     x = -x
   end
   local mantissa, exponent = math.frexp(x)
   if x == 0 then
      mantissa = 0
      exponent = 0
   else
      mantissa = (mantissa * 2 - 1) * 8388608
      exponent = exponent + 126
   end
   local v, byte = ""
   x, byte = grab_byte(mantissa); v = v..byte
   x, byte = grab_byte(x); v = v..byte
   x, byte = grab_byte(exponent * 128 + x); v = v..byte
   x, byte = grab_byte(sign * 128 + x); v = v..byte
   return v
end

pam.str2float = function(x)
  local sign = 1
  local mantissa = string.byte(x, 3) % 128

  for i = 2, 1, -1 do mantissa = mantissa * 256 + string.byte(x, i) end
  if string.byte(x, 4) > 127 then sign = -1 end
  local exponent = (string.byte(x, 4) % 128) * 2 + math.floor(string.byte(x, 3) / 128)
  if exponent == 0 then return 0 end
  mantissa = (math.ldexp(mantissa, -23) + 1) * sign
  return math.ldexp(mantissa, exponent - 127)
end

pam.int2str = function(n)
  n = (n < 0) and (4294967296 + n) or n
  return string.char((math.modf(n/16777216))%256, (math.modf(n/65536))%256, (math.modf(n/256))%256, n%256)
end

pam.str2int = function(x)
  b1, b2, b3, b4 = string.byte(x, 1, 4)
  local n = b1*16777216 + b2*65536 + b3*256 + b4
  n = (n > 2147483647) and (n - 4294967296) or n
  return n
end

pam.type = 0
pam.vertexes = {}
pam.triangles = {} -- x,y,z, string color(use string.byte() to decode)
pam.vertexFrames = {}
pam.paletteFrames = {}

-- modules
pam.additionalModules = {}
pam.modulesData = {}

pam.addModule = function(m)
  if (m == nil) or (m.name == nil) or ((m.pack == nil) and (m.unpack == nil)) then
    return false
  end

  table.insert(pam.additionalModules, m)

  return true
end

pam.removeModule = function(name)
  if (name == nil) then return false end

  for n, m in pairs(pam.additionalModules) do
    if m.name == name then
      table.remove(pam.additionalModules, n)
      return true
    end
  end

  return false
end

pam.removeAllModules = function()
  pam.additionalModules = {}
end

-- pam

pam.load = function(fileName)
  if (fileName ~= nil) and fs.exists(fileName) then
    local fileSize = fs.size(fileName)
    if fileSize < 12 then
      return false, "File size is too small" end

    local file = fs.open(fileName,"rb")
    local data = file:read(3)
    if data == "PAM" then
      pam.vertexes = {}
      pam.triangles = {}
      pam.vertexFrames = {}
      pam.paletteFrames = {}

      pam.type = file:read(1):byte()
      local vertsCount = pam.str2int(file:read(4))
      local trisCount = pam.str2int(file:read(4))

      for i = 1, vertsCount do -- vertexes
        if pam.type < 4 then
          table.insert(pam.vertexes, {pam.str2float(file:read(4)), pam.str2float(file:read(4)), pam.str2float(file:read(4))}) -- 3D vertexes
        elseif pam.type < 8 then
          table.insert(pam.vertexes, {pam.str2float(file:read(4)), pam.str2float(file:read(4))}) -- 2D vertexes
        end
      end
      os.sleep(0.001)

      for i = 1, trisCount do -- triangles
        table.insert(pam.triangles, {pam.str2int(file:read(4)), pam.str2int(file:read(4)), pam.str2int(file:read(4)), file:read(4)})
      end
      os.sleep(0.001)

      if (pam.type == 1) or (pam.type == 3) then -- 3D vertex animation
        local framesCount = pam.str2int(file:read(4))
        for i = 1, framesCount do
          local frameVertexes = {}
          for j = 1, vertsCount do
            table.insert(frameVertexes, {pam.str2float(file:read(4)), pam.str2float(file:read(4)), pam.str2float(file:read(4))})
          end
          table.insert(pam.vertexFrames, frameVertexes)
          os.sleep(0.001)
        end
      end

      if (pam.type == 5) or (pam.type == 7) then -- 2D vertex animation
        local framesCount = pam.str2int(file:read(4))
        for i = 1, framesCount do
          local frameVertexes = {}
          for j = 1, vertsCount do
            table.insert(frameVertexes, {pam.str2float(file:read(4)), pam.str2float(file:read(4))})
          end
          table.insert(pam.vertexFrames, frameVertexes)
          os.sleep(0.001)
        end
      end

      if (pam.type == 2) or (pam.type == 3) or
          (pam.type == 6) or (pam.type == 7) then -- palette animation
        local framesCount = pam.str2int(file:read(4))
        for i = 1, framesCount do
          local framePalette = {}
          for j = 1, trisCount do
            table.insert(framePalette, file:read(4))
          end
          table.insert(pam.paletteFrames, framePalette)
          os.sleep(0.001)
        end
      end

      for n, m in pairs(pam.additionalModules) do
        if (m ~= nil) and (m.unpack ~= nil) then
          local md = m.unpack(file, fileSize, pam)
          if md ~= nil then pam.modulesData[m.name] = md end
          os.sleep(0.001)
        end
      end

      file:close()
      return true
    else
      file:close()
      return false, "File has invalid format"
    end
  else
    return false, "File does not exists"
  end
end

pam.save = function(fileName)
  if fileName == nil then return false end

  if (#pam.vertexes < 3) and (#pam.triangles < 1) then return false end

  if #pam.additionalModules < 1 then
    if #pam.vertexes[1] == 3 then pam.type = 0
    else pam.type = 4 end

    if #pam.vertexFrames > 0 then
      pam.type = pam.type + 1
      if #pam.paletteFrames > 0 then
        pam.type = pam.type + 2
      end
    elseif #pam.paletteFrames > 0 then
      pam.type = pam.type + 1
    end
  end

  local data = "PAM"..string.char(pam.type)..pam.int2str(#pam.vertexes)..pam.int2str(#pam.triangles)

  for n, vert in pairs(pam.vertexes) do -- pack mesh
    local x,y,z = table.unpack(vert)
    data = data..pam.float2str(x)..pam.float2str(y)
    if pam.type < 4 then data = data..pam.float2str(z) end
  end
  os.sleep(0.001)

  for n, tri in pairs(pam.triangles) do
    local a,b,c,d = table.unpack(tri)
    data = data..pam.int2str(a)..pam.int2str(b)..pam.int2str(c)..d
  end
  os.sleep(0.001)

  if #pam.additionalModules < 1 then
    if #pam.vertexFrames > 0 then -- pack vertex animation
      data = data..pam.int2str(#pam.vertexFrames)
      for n, frame in pairs(pam.vertexFrames) do
        for n, vert in pairs(frame) do
          local x,y,z = table.unpack(vert)
          data = data..pam.float2str(x)..pam.float2str(y)
          if pam.type < 4 then data = data..pam.float2str(z) end
        end
      end
    end

    if #pam.paletteFrames > 0 then -- pack palette animation
      data = data..pam.int2str(#pam.paletteFrames)
      for n, frame in pairs(pam.paletteFrames) do
        for n, color in pairs(frame) do
          data = data..color
        end
      end
    end
    os.sleep(0.001)
  else
    for n, m in pairs(pam.additionalModules) do
      if (m ~= nil) and (m.pack ~= nil) and (pam.modulesData[m.name] ~= nil) then
        data = data..m.pack(pam.modulesData[m.name], pam)
        os.sleep(0.001)
      end
    end
  end

  local file = fs.open(fileName, "wb")
  file:write(data)
  file:close()

  return true
end

pam.loadMesh = function(fileName)
  if (fileName ~= nil) and fs.exists(fileName) then
    if fs.size(fileName) < 12 then
    return false, "File size is too small" end

    local file = fs.open(fileName,"rb")
    local data = file:read(3)
    if data == "PAM" then
      local vertexes = {}
      local triangles = {}

      local type = file:read(1):byte()
      local vertsCount = pam.str2int(file:read(4))
      local trisCount = pam.str2int(file:read(4))

      for i = 1, vertsCount do -- vertexes
        if pam.type < 4 then
          table.insert(vertexes, {pam.str2float(file:read(4)), pam.str2float(file:read(4)), pam.str2float(file:read(4))}) -- 3D vertexes
        elseif pam.type < 8 then
          table.insert(vertexes, {pam.str2float(file:read(4)), pam.str2float(file:read(4))}) -- 2D vertexes
        end
      end

      for i = 1, trisCount do -- triangles
        table.insert(triangles, {pam.str2int(file:read(4)), pam.str2int(file:read(4)), pam.str2int(file:read(4)), file:read(4)})
      end

      file:close()
      return true, type, vertexes, triangles
    else
      file:close()
      return false, "File has invalid format"
    end
  else
    return false, "File does not exists"
  end
end

local function lerpVertex(v1, v2, t)
  if #v1 == 3 then
    local v = {0,0,0}
    v[1] = (1-t)*v1[1] + t*v2[1];
    v[2] = (1-t)*v1[2] + t*v2[2];
    v[3] = (1-t)*v1[3] + t*v2[3];
    return v
  else
    local v = {0,0}
    v[1] = (1-t)*v1[1] + t*v2[1];
    v[2] = (1-t)*v1[2] + t*v2[2];
    return v
  end
end

local function lerpColor(c1, c2, t)
  local c = {0,0,0,0}
  c[1] = math.floor((1-t)*c1[1] + t*c2[1]);
  c[2] = math.floor((1-t)*c1[2] + t*c2[2]);
  c[3] = math.floor((1-t)*c1[3] + t*c2[3]);
  c[4] = math.floor((1-t)*c1[4] + t*c2[4]);
  return c
end

pam.lerpVertexFrames = function(f1, f2, t)
  if f1 == f2 then
    return nil, "Frames must be different"
  end

  local firstFrame
  local secondFrame
  local outputFrame = {}

  if f1 == 0 then
    firstFrame = pam.vertexes
  elseif (f1 < 1) or (f1 > #pam.vertexFrames) then
    return nil, "Invalid first frame"
  else
    firstFrame = pam.vertexFrames[f1]
  end
  if f2 == 0 then
    secondFrame = pam.vertexes
  elseif (f2 < 1) or (f2 > #pam.vertexFrames) then
    return nil, "Invalid second frame"
  else
    secondFrame = pam.vertexFrames[f2]
  end

  for i=1, #firstFrame do
    table.insert(outputFrame, lerpVertex(firstFrame[i], secondFrame[i], t))
  end

  return outputFrame
end

pam.lerpPaletteFrames = function(f1, f2, t)
  if f1 == f2 then
    return nil, "Frames must be different"
  end

  local firstFrame
  local secondFrame
  local outputFrame = {}

  if (f1 < 0) or (f1 > #pam.paletteFrames) then
    return nil, "Invalid first frame"
  elseif f1 ~= 0 then
    firstFrame = pam.paletteFrames[f1];
  end
  if (f2 < 0) or (f2 > #pam.paletteFrames) then
    return nil, "Invalid second frame"
  elseif f2 ~= 0 then
    secondFrame = pam.paletteFrames[f2]
  end

  for i=1, #pam.triangles do
    local c1
    local c2
    if f1 == 0 then
      c1 = table.pack(pam.triangles[i][4]:byte(1,4))
    else
      c1 = table.pack(firstFrame[i]:byte(1,4))
    end
    if f2 == 0 then
      c2 = table.pack(pam.triangles[i][4]:byte(1,4))
    else
      c2 = table.pack(secondFrame[i]:byte(1,4))
    end
    table.insert(outputFrame, lerpColor(c1, c2, t))
  end

  return outputFrame
end

return pam