forked from VoxeLibre/VoxeLibre
93 lines
2.3 KiB
Lua
93 lines
2.3 KiB
Lua
tga_encoder = {}
|
|
|
|
local image = setmetatable({}, {
|
|
__call = function(self, ...)
|
|
local t = setmetatable({}, {__index = self})
|
|
t:constructor(...)
|
|
return t
|
|
end,
|
|
})
|
|
|
|
function image:constructor(pixels)
|
|
self.data = ""
|
|
self.pixels = pixels
|
|
self.width = #pixels[1]
|
|
self.height = #pixels
|
|
|
|
self:encode()
|
|
end
|
|
|
|
function image:encode_colormap_spec()
|
|
self.data = self.data
|
|
.. string.char(0, 0) -- first entry index
|
|
.. string.char(0, 0) -- number of entries
|
|
.. string.char(0) -- bits per pixel
|
|
end
|
|
|
|
function image:encode_image_spec()
|
|
self.data = self.data
|
|
.. string.char(0, 0) -- X-origin
|
|
.. string.char(0, 0) -- Y-origin
|
|
.. string.char(self.width % 256, math.floor(self.width / 256)) -- width
|
|
.. string.char(self.height % 256, math.floor(self.height / 256)) -- height
|
|
.. string.char(24) -- pixel depth (RGB = 3 bytes = 24 bits)
|
|
.. string.char(0) -- image descriptor
|
|
end
|
|
|
|
function image:encode_header()
|
|
self.data = self.data
|
|
.. string.char(0) -- image id
|
|
.. string.char(0) -- color map type
|
|
.. string.char(10) -- image type (RLE RGB = 10)
|
|
self:encode_colormap_spec() -- color map specification
|
|
self:encode_image_spec() -- image specification
|
|
end
|
|
|
|
function image:encode_data()
|
|
local current_pixel = ''
|
|
local previous_pixel = ''
|
|
local count = 1
|
|
local packets = {}
|
|
local rle_packet = ''
|
|
for _, row in ipairs(self.pixels) do
|
|
for _, pixel in ipairs(row) do
|
|
current_pixel = string.char(pixel[3], pixel[2], pixel[1])
|
|
if current_pixel ~= previous_pixel or count == 128 then
|
|
packets[#packets +1] = rle_packet
|
|
count = 1
|
|
previous_pixel = current_pixel
|
|
else
|
|
count = count + 1
|
|
end
|
|
rle_packet = string.char(128 + count - 1) .. current_pixel
|
|
end
|
|
end
|
|
packets[#packets +1] = rle_packet
|
|
self.data = self.data .. table.concat(packets)
|
|
end
|
|
|
|
function image:encode_footer()
|
|
self.data = self.data
|
|
.. string.char(0, 0, 0, 0) -- extension area offset
|
|
.. string.char(0, 0, 0, 0) -- developer area offset
|
|
.. "TRUEVISION-XFILE"
|
|
.. "."
|
|
.. string.char(0)
|
|
end
|
|
|
|
function image:encode()
|
|
self:encode_header() -- header
|
|
-- no color map and image id data
|
|
self:encode_data() -- encode data
|
|
-- no extension or developer area
|
|
self:encode_footer() -- footer
|
|
end
|
|
|
|
function image:save(filename)
|
|
local f = assert(io.open(filename, "wb"))
|
|
f:write(self.data)
|
|
f:close()
|
|
end
|
|
|
|
tga_encoder.image = image
|