110 lines
2.2 KiB
Lua
110 lines
2.2 KiB
Lua
|
tga_encoder = {}
|
||
|
|
|
||
|
|
local LUA_ARGS_LIMIT = 1000
|
||
|
|
|
||
|
|
local image = setmetatable({}, {
|
||
|
|
__call = function(self, ...)
|
||
|
|
local t = setmetatable({}, {__index = self})
|
||
|
|
t:constructor(...)
|
||
|
|
return t
|
||
|
|
end,
|
||
|
|
})
|
||
|
|
|
||
|
|
function image:constructor(pixels)
|
||
|
|
self.bytes = {}
|
||
|
|
self.chunks = {self.bytes}
|
||
|
|
self.pixels = pixels
|
||
|
|
self.width = #pixels[1]
|
||
|
|
self.height = #pixels
|
||
|
|
|
||
|
|
self:encode()
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:insert(byte)
|
||
|
|
table.insert(self.bytes, byte)
|
||
|
|
if #self.bytes == LUA_ARGS_LIMIT then
|
||
|
|
self.bytes = {}
|
||
|
|
table.insert(self.chunks, self.bytes)
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:littleendian(size, value)
|
||
|
|
for i = 1, size do
|
||
|
|
local byte = value % 256
|
||
|
|
value = value - byte
|
||
|
|
value = value / 256
|
||
|
|
self:insert(byte)
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:encode_colormap_spec()
|
||
|
|
-- first entry index
|
||
|
|
self:littleendian(2, 0)
|
||
|
|
-- number of entries
|
||
|
|
self:littleendian(2, 0)
|
||
|
|
-- number of bits per pixel
|
||
|
|
self:insert(0)
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:encode_image_spec()
|
||
|
|
-- X- and Y- origin
|
||
|
|
self:littleendian(2, 0)
|
||
|
|
self:littleendian(2, 0)
|
||
|
|
-- width and height
|
||
|
|
self:littleendian(2, self.width)
|
||
|
|
self:littleendian(2, self.height)
|
||
|
|
-- pixel depth
|
||
|
|
self:insert(24)
|
||
|
|
-- image descriptor
|
||
|
|
self:insert(0)
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:encode_header()
|
||
|
|
-- id length
|
||
|
|
self:insert(0) -- no image id info
|
||
|
|
-- color map type
|
||
|
|
self:insert(0) -- no color map
|
||
|
|
-- image type
|
||
|
|
self:insert(2) -- uncompressed true-color image
|
||
|
|
-- color map specification
|
||
|
|
self:encode_colormap_spec()
|
||
|
|
-- image specification
|
||
|
|
self:encode_image_spec()
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:encode_data()
|
||
|
|
for _, row in ipairs(self.pixels) do
|
||
|
|
for _, pixel in ipairs(row) do
|
||
|
|
self:insert(pixel[3])
|
||
|
|
self:insert(pixel[2])
|
||
|
|
self:insert(pixel[1])
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:encode()
|
||
|
|
-- encode header
|
||
|
|
self:encode_header()
|
||
|
|
-- no color map and image id data
|
||
|
|
-- encode data
|
||
|
|
self:encode_data()
|
||
|
|
-- no extension area
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:get_data()
|
||
|
|
local data = ""
|
||
|
|
for _, bytes in ipairs(self.chunks) do
|
||
|
|
data = data .. string.char(unpack(bytes))
|
||
|
|
end
|
||
|
|
return data .. string.char(0, 0, 0, 0) .. string.char(0, 0, 0, 0) .. "TRUEVISION-XFILE." .. string.char(0)
|
||
|
|
end
|
||
|
|
|
||
|
|
function image:save(filename)
|
||
|
|
self.data = self.data or self:get_data()
|
||
|
|
local f = assert(io.open(filename, "w"))
|
||
|
|
f:write(self.data)
|
||
|
|
f:close()
|
||
|
|
end
|
||
|
|
|
||
|
|
tga_encoder.image = image
|