Use RLE compression in tga_encoder

This commit is contained in:
Nils Dagsson Moskopp 2021-11-04 01:53:58 +01:00
parent b88579b52e
commit 52e5c955f0
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@ -38,18 +38,31 @@ function image:encode_header()
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)
.. 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 encoded = ''
local rle_packet = ''
for _, row in ipairs(self.pixels) do
for _, pixel in ipairs(row) do
self.data = self.data
.. string.char(pixel[3], pixel[2], pixel[1])
current_pixel = string.char(pixel[3], pixel[2], pixel[1])
if current_pixel ~= previous_pixel or count == 128 then
encoded = encoded .. rle_packet
count = 1
previous_pixel = current_pixel
else
count = count + 1
end
rle_packet = string.char(128 + count - 1) .. current_pixel
end
end
self.data = self.data .. encoded .. rle_packet
end
function image:encode_footer()