From b88579b52e8ed66beca2b97871db3853d5260dd7 Mon Sep 17 00:00:00 2001 From: Elias Fleckenstein Date: Sun, 2 May 2021 17:47:46 +0200 Subject: [PATCH] Add updated tga_encoder --- init.lua | 97 +++++++++++++++++++------------------------------------- 1 file changed, 33 insertions(+), 64 deletions(-) diff --git a/init.lua b/init.lua index 45b9e85a2..96afda5e1 100644 --- a/init.lua +++ b/init.lua @@ -1,7 +1,5 @@ tga_encoder = {} -local LUA_ARGS_LIMIT = 1000 - local image = setmetatable({}, { __call = function(self, ...) local t = setmetatable({}, {__index = self}) @@ -11,8 +9,7 @@ local image = setmetatable({}, { }) function image:constructor(pixels) - self.bytes = {} - self.chunks = {self.bytes} + self.data = "" self.pixels = pixels self.width = #pixels[1] self.height = #pixels @@ -20,87 +17,59 @@ function image:constructor(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) + 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() - -- 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) + 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() - -- 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() + self.data = self.data + .. string.char(0) -- image id + .. string.char(0) -- color map type + .. string.char(2) -- image type (uncompressed true-color image = 2) + self:encode_colormap_spec() -- color map specification + self:encode_image_spec() -- image specification 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]) + self.data = self.data + .. string.char(pixel[3], pixel[2], 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 +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: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) +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) - self.data = self.data or self:get_data() local f = assert(io.open(filename, "w")) f:write(self.data) f:close()