Allow encoding RGB images as B8G8R8
Nils Dagsson Moskopp
parent
1b48c3f539
commit
9af0719df8
|
|
@ -46,4 +46,5 @@ for x = 1,16,1 do -- left to right
|
|||
pixels[z][x] = color
|
||||
end
|
||||
end
|
||||
tga_encoder.image(pixels):save("gradients.tga")
|
||||
tga_encoder.image(pixels, {pixel_depth=16}):save("gradients_16bpp.tga")
|
||||
tga_encoder.image(pixels, {pixel_depth=24}):save("gradients_24bpp.tga")
|
||||
|
|
|
|||
111
init.lua
111
init.lua
|
|
@ -8,13 +8,16 @@ local image = setmetatable({}, {
|
|||
end,
|
||||
})
|
||||
|
||||
function image:constructor(pixels)
|
||||
function image:constructor(pixels, properties)
|
||||
local properties = properties or {}
|
||||
local pixel_depth = properties.pixel_depth or 16
|
||||
|
||||
self.data = ""
|
||||
self.pixels = pixels
|
||||
self.width = #pixels[1]
|
||||
self.height = #pixels
|
||||
|
||||
self:encode()
|
||||
self:encode(pixel_depth)
|
||||
end
|
||||
|
||||
function image:encode_colormap_spec()
|
||||
|
|
@ -24,26 +27,38 @@ function image:encode_colormap_spec()
|
|||
.. string.char(0) -- bits per pixel
|
||||
end
|
||||
|
||||
function image:encode_image_spec()
|
||||
function image:encode_image_spec(pixel_depth)
|
||||
assert(
|
||||
16 == pixel_depth or -- (A1R5G5B5 = 2 bytes = 16 bits)
|
||||
24 == pixel_depth -- (B8G8R8 = 3 bytes = 24 bits)
|
||||
)
|
||||
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(16) -- pixel depth (ARRRRRGGGGGBBBBB = 2 bytes = 16 bits)
|
||||
.. string.char(pixel_depth)
|
||||
.. string.char(0) -- image descriptor
|
||||
end
|
||||
|
||||
function image:encode_header()
|
||||
function image:encode_header(pixel_depth)
|
||||
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
|
||||
self:encode_image_spec(pixel_depth) -- image specification
|
||||
end
|
||||
|
||||
function image:encode_data()
|
||||
function image:encode_data(pixel_depth)
|
||||
if 16 == pixel_depth then
|
||||
self:encode_data_a1r5g5b5_rle()
|
||||
elseif 24 == pixel_depth then
|
||||
self:encode_data_r8g8b8_rle()
|
||||
end
|
||||
end
|
||||
|
||||
function image:encode_data_a1r5g5b5_rle()
|
||||
local colorword = nil
|
||||
local previous_r = nil
|
||||
local previous_g = nil
|
||||
|
|
@ -132,6 +147,82 @@ function image:encode_data()
|
|||
self.data = self.data .. table.concat(packets)
|
||||
end
|
||||
|
||||
function image:encode_data_r8g8b8_rle()
|
||||
local previous_r = nil
|
||||
local previous_g = nil
|
||||
local previous_b = nil
|
||||
local raw_pixel = ''
|
||||
local raw_pixels = {}
|
||||
local count = 1
|
||||
local packets = {}
|
||||
local raw_packet = ''
|
||||
local rle_packet = ''
|
||||
for _, row in ipairs(self.pixels) do
|
||||
for _, pixel in ipairs(row) do
|
||||
if pixel[1] ~= previous_r or pixel[2] ~= previous_g or pixel[3] ~= previous_b or count == 128 then
|
||||
if nil ~= previous_r then
|
||||
if 1 == count then
|
||||
-- remember pixel verbatim for raw encoding
|
||||
raw_pixel = string.char(previous_b, previous_g, previous_r)
|
||||
raw_pixels[#raw_pixels + 1] = raw_pixel
|
||||
if 128 == #raw_pixels then
|
||||
raw_packet = string.char(#raw_pixels - 1)
|
||||
packets[#packets + 1] = raw_packet
|
||||
for i=1, #raw_pixels do
|
||||
packets[#packets +1] = raw_pixels[i]
|
||||
end
|
||||
raw_pixels = {}
|
||||
end
|
||||
else
|
||||
-- encode raw pixels, if any
|
||||
if #raw_pixels > 0 then
|
||||
raw_packet = string.char(#raw_pixels - 1)
|
||||
packets[#packets + 1] = raw_packet
|
||||
for i=1, #raw_pixels do
|
||||
packets[#packets +1] = raw_pixels[i]
|
||||
end
|
||||
raw_pixels = {}
|
||||
end
|
||||
-- RLE encoding
|
||||
rle_packet = string.char(128 + count - 1, previous_b, previous_g, previous_r)
|
||||
packets[#packets +1] = rle_packet
|
||||
end
|
||||
end
|
||||
count = 1
|
||||
previous_r = pixel[1]
|
||||
previous_g = pixel[2]
|
||||
previous_b = pixel[3]
|
||||
else
|
||||
count = count + 1
|
||||
end
|
||||
end
|
||||
end
|
||||
if 1 == count then
|
||||
raw_pixel = string.char(previous_b, previous_g, previous_r)
|
||||
raw_pixels[#raw_pixels + 1] = raw_pixel
|
||||
raw_packet = string.char(#raw_pixels - 1)
|
||||
packets[#packets + 1] = raw_packet
|
||||
for i=1, #raw_pixels do
|
||||
packets[#packets +1] = raw_pixels[i]
|
||||
end
|
||||
raw_pixels = {}
|
||||
else
|
||||
-- encode raw pixels, if any
|
||||
if #raw_pixels > 0 then
|
||||
raw_packet = string.char(#raw_pixels - 1)
|
||||
packets[#packets + 1] = raw_packet
|
||||
for i=1, #raw_pixels do
|
||||
packets[#packets +1] = raw_pixels[i]
|
||||
end
|
||||
raw_pixels = {}
|
||||
end
|
||||
-- RLE encoding
|
||||
rle_packet = string.char(128 + count - 1, previous_b, previous_g, previous_r)
|
||||
packets[#packets +1] = rle_packet
|
||||
end
|
||||
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
|
||||
|
|
@ -141,10 +232,10 @@ function image:encode_footer()
|
|||
.. string.char(0)
|
||||
end
|
||||
|
||||
function image:encode()
|
||||
self:encode_header() -- header
|
||||
function image:encode(pixel_depth)
|
||||
self:encode_header(pixel_depth) -- header
|
||||
-- no color map and image id data
|
||||
self:encode_data() -- encode data
|
||||
self:encode_data(pixel_depth) -- encode data
|
||||
-- no extension or developer area
|
||||
self:encode_footer() -- footer
|
||||
end
|
||||
|
|
|
|||
Loading…
Reference in New Issue