mirror of
https://github.com/appgurueu/modlib.git
synced 2024-11-22 07:13:45 +01:00
Add experimental decode_png & convert_png_to_argb8
This commit is contained in:
Lars Mueller
parent
25aa5c6e82
commit
7d4aa0fec1
@ -50,6 +50,11 @@ for filename, comps in pairs{
|
||||
},
|
||||
collisionboxes = {
|
||||
"get_node_collisionboxes"
|
||||
},
|
||||
png = {
|
||||
"decode_png",
|
||||
"convert_png_to_argb8",
|
||||
"encode_png",
|
||||
}
|
||||
} do
|
||||
for _, component in pairs(comps) do
|
||||
|
||||
@ -1,115 +0,0 @@
|
||||
if minetest.encode_png then
|
||||
(...).encode_png = minetest.encode_png
|
||||
return
|
||||
end
|
||||
|
||||
local assert, char, ipairs, insert, concat, floor = assert, string.char, ipairs, table.insert, table.concat, math.floor
|
||||
|
||||
-- TODO move to modlib.bit eventually
|
||||
local bit_xor = bit.xor or function(a, b)
|
||||
local res = 0
|
||||
local bit = 1
|
||||
for _ = 1, 32 do
|
||||
if a % 2 ~= b % 2 then
|
||||
res = res + bit
|
||||
end
|
||||
a = floor(a / 2)
|
||||
b = floor(b / 2)
|
||||
bit = bit * 2
|
||||
end
|
||||
return res
|
||||
end
|
||||
|
||||
local crc_table = {}
|
||||
for i = 0, 255 do
|
||||
local c = i
|
||||
for _ = 0, 7 do
|
||||
if c % 2 > 0 then
|
||||
c = bit_xor(0xEDB88320, floor(c / 2))
|
||||
else
|
||||
c = floor(c / 2)
|
||||
end
|
||||
end
|
||||
crc_table[i] = c
|
||||
end
|
||||
|
||||
local function encode_png(width, height, data, compression, raw_write)
|
||||
local write = raw_write
|
||||
local function byte(value)
|
||||
write(char(value))
|
||||
end
|
||||
local function _uint(value)
|
||||
local div = 0x1000000
|
||||
for _ = 1, 4 do
|
||||
byte(floor(value / div) % 0x100)
|
||||
div = div / 0x100
|
||||
end
|
||||
end
|
||||
local function uint(value)
|
||||
assert(value < 2^31)
|
||||
_uint(value)
|
||||
end
|
||||
local chunk_content
|
||||
local function chunk_write(text)
|
||||
insert(chunk_content, text)
|
||||
end
|
||||
local function chunk(type)
|
||||
chunk_content = {}
|
||||
write = chunk_write
|
||||
write(type)
|
||||
end
|
||||
local function end_chunk()
|
||||
write = raw_write
|
||||
local chunk_len = 0
|
||||
for i = 2, #chunk_content do
|
||||
chunk_len = chunk_len + #chunk_content[i]
|
||||
end
|
||||
uint(chunk_len)
|
||||
write(concat(chunk_content))
|
||||
local chunk_crc = 0xFFFFFFFF
|
||||
for _, text in ipairs(chunk_content) do
|
||||
for i = 1, #text do
|
||||
chunk_crc = bit_xor(crc_table[bit_xor(chunk_crc % 0x100, text:byte(i))], floor(chunk_crc / 0x100))
|
||||
end
|
||||
end
|
||||
_uint(bit_xor(chunk_crc, 0xFFFFFFFF))
|
||||
end
|
||||
-- Signature
|
||||
write"\137\80\78\71\13\10\26\10"
|
||||
chunk"IHDR"
|
||||
uint(width)
|
||||
uint(height)
|
||||
-- Always use bit depth 8
|
||||
byte(8)
|
||||
-- Always use color type "truecolor with alpha"
|
||||
byte(6)
|
||||
-- Compression method: deflate
|
||||
byte(0)
|
||||
-- Filter method: PNG filters
|
||||
byte(0)
|
||||
-- No interlace
|
||||
byte(0)
|
||||
end_chunk()
|
||||
chunk"IDAT"
|
||||
local data_rope = {}
|
||||
for y = 0, height - 1 do
|
||||
local base_index = y * width
|
||||
insert(data_rope, "\0")
|
||||
for x = 1, width do
|
||||
local colorspec = modlib.minetest.colorspec.from_any(data[base_index + x])
|
||||
insert(data_rope, char(colorspec.r, colorspec.g, colorspec.b, colorspec.a))
|
||||
end
|
||||
end
|
||||
write(minetest.compress(type(data) == "string" and data or concat(data_rope), "deflate", compression))
|
||||
end_chunk()
|
||||
chunk"IEND"
|
||||
end_chunk()
|
||||
end
|
||||
|
||||
(...).encode_png = function(width, height, data, compression)
|
||||
local rope = {}
|
||||
encode_png(width, height, data, compression or 9, function(text)
|
||||
insert(rope, text)
|
||||
end)
|
||||
return concat(rope)
|
||||
end
|
||||
425
minetest/png.lua
Normal file
425
minetest/png.lua
Normal file
@ -0,0 +1,425 @@
|
||||
local signature = "\137\80\78\71\13\10\26\10"
|
||||
|
||||
local assert, char, ipairs, insert, concat, abs, floor = assert, string.char, ipairs, table.insert, table.concat, math.abs, math.floor
|
||||
|
||||
-- TODO move to modlib.bit eventually
|
||||
local bit_xor = bit.xor or function(a, b)
|
||||
local res = 0
|
||||
local bit = 1
|
||||
for _ = 1, 32 do
|
||||
if a % 2 ~= b % 2 then
|
||||
res = res + bit
|
||||
end
|
||||
a = floor(a / 2)
|
||||
b = floor(b / 2)
|
||||
bit = bit * 2
|
||||
end
|
||||
return res
|
||||
end
|
||||
|
||||
local crc_table = {}
|
||||
for i = 0, 255 do
|
||||
local c = i
|
||||
for _ = 0, 7 do
|
||||
if c % 2 > 0 then
|
||||
c = bit_xor(0xEDB88320, floor(c / 2))
|
||||
else
|
||||
c = floor(c / 2)
|
||||
end
|
||||
end
|
||||
crc_table[i] = c
|
||||
end
|
||||
|
||||
local function update_crc(crc, text)
|
||||
for i = 1, #text do
|
||||
crc = bit_xor(crc_table[bit_xor(crc % 0x100, text:byte(i))], floor(crc / 0x100))
|
||||
end
|
||||
return crc
|
||||
end
|
||||
|
||||
|
||||
local color_types = {
|
||||
[0] = {
|
||||
color = "grayscale"
|
||||
},
|
||||
[2] = {
|
||||
color = "truecolor"
|
||||
},
|
||||
[3] = {
|
||||
color = "palette",
|
||||
depth = 8
|
||||
},
|
||||
[4] = {
|
||||
color = "grayscale",
|
||||
alpha = true
|
||||
},
|
||||
[6] = {
|
||||
color = "truecolor",
|
||||
alpha = true
|
||||
}
|
||||
}
|
||||
local set = modlib.table.set
|
||||
local allowed_bit_depths = {
|
||||
[0] = set{1, 2, 4, 8, 16},
|
||||
[2] = set{8, 16},
|
||||
[3] = set{1, 2, 4, 8},
|
||||
[4] = set{8, 16},
|
||||
[6] = set{8, 16}
|
||||
}
|
||||
local samples = {
|
||||
grayscale = 1,
|
||||
palette = 1,
|
||||
truecolor = 3
|
||||
}
|
||||
|
||||
(...).decode_png = function(stream)
|
||||
local chunk_crc
|
||||
local function read(n)
|
||||
local text = stream:read(n)
|
||||
assert(#text == n)
|
||||
if chunk_crc then
|
||||
chunk_crc = update_crc(chunk_crc, text)
|
||||
end
|
||||
return text
|
||||
end
|
||||
local function byte()
|
||||
return read(1):byte()
|
||||
end
|
||||
local function _uint()
|
||||
return 0x1000000 * byte() + 0x10000 * byte() + 0x100 * byte() + byte()
|
||||
end
|
||||
local function uint()
|
||||
local val = _uint()
|
||||
assert(val < 2^31, "uint out of range")
|
||||
return val
|
||||
end
|
||||
local function check_crc()
|
||||
local crc = chunk_crc
|
||||
chunk_crc = nil
|
||||
if _uint() ~= bit_xor(crc, 0xFFFFFFFF) then
|
||||
error("CRC mismatch", 2)
|
||||
end
|
||||
end
|
||||
|
||||
assert(read(8) == signature, "PNG signature expected")
|
||||
|
||||
local IHDR_len = uint()
|
||||
assert(IHDR_len == 13, "invalid IHDR length")
|
||||
chunk_crc = 0xFFFFFFFF
|
||||
assert(read(4) == "IHDR", "IHDR chunk expected")
|
||||
local width = uint()
|
||||
assert(width > 0)
|
||||
local height = uint()
|
||||
assert(height > 0)
|
||||
local bit_depth = byte()
|
||||
local color_type_number = byte()
|
||||
local color_type = assert(color_types[color_type_number], "invalid color type")
|
||||
if color_type.color ~= "palette" then
|
||||
color_type.depth = bit_depth
|
||||
end
|
||||
assert(allowed_bit_depths[color_type_number][bit_depth], "disallowed bit depth for color type")
|
||||
local compression_method = byte()
|
||||
assert(compression_method == 0, "unsupported compression method")
|
||||
local filter_method = byte()
|
||||
assert(filter_method == 0, "unsupported filter method")
|
||||
local interlace_method = byte()
|
||||
assert(interlace_method <= 1, "unsupported interlace method")
|
||||
local adam7 = interlace_method == 1
|
||||
assert(not adam7, "adam7 interlacing not supported yet")
|
||||
check_crc() -- IHDR CRC
|
||||
|
||||
local palette
|
||||
local alpha
|
||||
local source_gamma
|
||||
local idat_content = {}
|
||||
local idat_allowed = true
|
||||
local iend
|
||||
repeat
|
||||
local chunk_length = uint()
|
||||
chunk_crc = 0xFFFFFFFF
|
||||
local chunk_type = read(4)
|
||||
if chunk_type == "IDAT" then
|
||||
assert(idat_allowed, "no chunks inbetween IDAT chunks allowed")
|
||||
if color_type.color == "palette" then
|
||||
assert(palette, "PLTE chunk expected")
|
||||
end
|
||||
insert(idat_content, read(chunk_length))
|
||||
else
|
||||
if next(idat_content) then
|
||||
-- Non-IDAT chunk, no IDAT chunks allowed anymore
|
||||
idat_allowed = false
|
||||
end
|
||||
if chunk_type == "PLTE" then
|
||||
assert(color_type.color ~= "grayscale")
|
||||
assert(not palette, "double PLTE chunk")
|
||||
assert(idat_allowed, "PLTE after IDAT chunks")
|
||||
palette = {}
|
||||
local entries = chunk_length / 3
|
||||
assert(entries % 1 == 0 and entries >= 1 and entries <= 2^bit_depth, "invalid PLTE chunk length")
|
||||
for i = 1, entries do
|
||||
palette[i] = 0x10000 * byte() + 0x100 * byte() + byte() -- RGB
|
||||
end
|
||||
elseif chunk_type == "tRNS" then
|
||||
assert(not color_type.alpha, "unexpected tRNS chunk")
|
||||
assert(idat_allowed, "tRNS after IDAT chunks")
|
||||
if color_type.color == "palette" then
|
||||
assert(palette, "PLTE chunk expected")
|
||||
alpha = {}
|
||||
for i = 1, chunk_length do
|
||||
alpha[i] = byte()
|
||||
end
|
||||
elseif color_type.color == "grayscale" then
|
||||
assert(chunk_length == 2)
|
||||
alpha = 0x100 * byte() + byte()
|
||||
else
|
||||
assert(color_type.color == "truecolor")
|
||||
assert(chunk_length == 6)
|
||||
alpha = ((((byte() * 0x100 + byte()) * 0x100 + byte()) * 0x100 + byte()) * 0x100 + byte()) * 0x100 + byte() -- 16-bit RGB
|
||||
end
|
||||
elseif chunk_type == "gAMA" then
|
||||
assert(not palette, "gAMA after PLTE chunk")
|
||||
assert(idat_allowed, "gAMA after IDAT chunks")
|
||||
assert(chunk_length == 4)
|
||||
source_gamma = uint() / 1e5
|
||||
elseif chunk_type == "IEND" then
|
||||
iend = true
|
||||
else
|
||||
-- Check whether the fifth bit of the first byte is set (upper vs. lowercase ASCII)
|
||||
local ancillary = floor(chunk_type:byte(1) % (2^6)) >= 2^5
|
||||
if not ancillary then
|
||||
error(("unsupported critical chunk: %q"):format(chunk_type))
|
||||
end
|
||||
read(chunk_length)
|
||||
end
|
||||
end
|
||||
check_crc()
|
||||
until iend
|
||||
assert(next(idat_content), "no IDAT chunk")
|
||||
idat_content = minetest.decompress(concat(idat_content), "deflate")
|
||||
--[[
|
||||
For memory efficiency, we try to pack everything in a single number:
|
||||
Grayscale/lightness: AY
|
||||
Palette: ARGB
|
||||
Truecolor (8-bit): ARGB
|
||||
Truecolor (16-bit): RGB + A
|
||||
(64 bits required, packing non-mantissa bits isn't practical) => separate table with alpha values
|
||||
]]
|
||||
local data = {}
|
||||
local alpha_data = {}
|
||||
local bits_per_pixel = (samples[color_type.color] + (color_type.alpha and 1 or 0)) * bit_depth
|
||||
local bytes_per_pixel = math.ceil(bits_per_pixel / 8)
|
||||
local scanline_bytecount = math.ceil(width * bits_per_pixel / 8)
|
||||
local previous_scanline
|
||||
for y = 0, height - 1 do
|
||||
local idat_base_index = y * (scanline_bytecount + 1) + 1
|
||||
local filtering = idat_content:byte(idat_base_index)
|
||||
local scanline = {}
|
||||
for i = 1, scanline_bytecount do
|
||||
local val = idat_content:byte(idat_base_index + i)
|
||||
local left = scanline[i - bytes_per_pixel] or 0
|
||||
local up = previous_scanline and previous_scanline[i] or 0
|
||||
local left_up = previous_scanline and previous_scanline[i - bytes_per_pixel] or 0
|
||||
-- Undo lossless filter
|
||||
if filtering == 0 then -- None
|
||||
scanline[i] = val
|
||||
elseif filtering == 1 then -- Sub
|
||||
scanline[i] = (left + val) % 0x100
|
||||
elseif filtering == 2 then -- Up
|
||||
scanline[i] = (up + val) % 0x100
|
||||
elseif filtering == 3 then -- Average
|
||||
scanline[i] = (floor((left + up) / 2) + val) % 0x100
|
||||
elseif filtering == 4 then -- Paeth
|
||||
local p = left + up - left_up
|
||||
local p_left = abs(p - left)
|
||||
local p_up = abs(p - up)
|
||||
local p_left_up = abs(p - left_up)
|
||||
local p_res
|
||||
if p_left <= p_up and p_left <= p_left_up then
|
||||
p_res = left
|
||||
elseif p_up <= p_left_up then
|
||||
p_res = up
|
||||
else
|
||||
p_res = left_up
|
||||
end
|
||||
scanline[i] = (p_res + val) % 0x100
|
||||
else
|
||||
error("invalid filtering method: " .. filtering)
|
||||
end
|
||||
assert(scanline[i] >= 0 and scanline[i] <= 255 and scanline[i] % 1 == 0)
|
||||
end
|
||||
local bit = 0
|
||||
local function sample()
|
||||
local byte_idx = 1 + floor(bit / 8)
|
||||
bit = bit + bit_depth
|
||||
local byte = scanline[byte_idx]
|
||||
if bit_depth == 16 then
|
||||
return byte * 0x100 + scanline[byte_idx + 1]
|
||||
end
|
||||
if bit_depth == 8 then
|
||||
return byte
|
||||
end
|
||||
assert(bit_depth == 1 or bit_depth == 2 or bit_depth == 4)
|
||||
local low = 2^(-bit % 8)
|
||||
return floor(byte / low) % (2^bit_depth)
|
||||
end
|
||||
for x = 0, width - 1 do
|
||||
local data_index = y * width + x + 1
|
||||
if color_type.color == "palette" then
|
||||
local palette_index = sample()
|
||||
local rgb = assert(palette[palette_index + 1], "palette index out of range")
|
||||
-- Index alpha table if available
|
||||
local a = alpha and alpha[palette_index + 1] or 255
|
||||
data[data_index] = a * 0x1000000 + rgb
|
||||
elseif color_type.color == "grayscale" then
|
||||
local Y = sample()
|
||||
local a = 2^bit_depth - 1
|
||||
if color_type.alpha then
|
||||
a = sample()
|
||||
elseif alpha == Y then
|
||||
a = 0 -- Convert grayscale to transparency
|
||||
end
|
||||
data[data_index] = a * (2^bit_depth) + Y
|
||||
else
|
||||
assert(color_type.color == "truecolor")
|
||||
local r, g, b = sample(), sample(), sample()
|
||||
local rgb16 = r * 0x100000000 + g * 0x10000 + b
|
||||
local a = 2^bit_depth - 1
|
||||
if color_type.alpha then
|
||||
a = sample()
|
||||
elseif alpha == rgb16 then
|
||||
a = 0 -- Convert color to transparency
|
||||
end
|
||||
if bit_depth == 8 then
|
||||
data[data_index] = a * 0x1000000 + r * 0x10000 + g * 0x100 + b
|
||||
else
|
||||
assert(bit_depth == 16)
|
||||
-- Pack only RGB in data, alpha goes in a different table
|
||||
-- 3 * 16 = 48 bytes can still be held accurately by the double mantissa
|
||||
data[data_index] = rgb16
|
||||
alpha_data[data_index] = a
|
||||
end
|
||||
end
|
||||
end
|
||||
-- Each byte of the scanline must have been read from
|
||||
assert(bit >= #scanline * 8 - 7)
|
||||
previous_scanline = scanline
|
||||
end
|
||||
return {
|
||||
width = width,
|
||||
height = height,
|
||||
color_type = color_type,
|
||||
source_gamma = source_gamma,
|
||||
data = data,
|
||||
alpha_data = next(alpha_data) and alpha_data
|
||||
}
|
||||
end
|
||||
|
||||
local function rescale_depth(sample, source, target)
|
||||
if source == target then
|
||||
return sample
|
||||
end
|
||||
return floor((sample / (2^source - 1) * (2^target - 1)) + 0.5)
|
||||
end
|
||||
-- In-place lossy (if bit depth = 16) conversion to ARGB8
|
||||
(...).convert_png_to_argb8 = function(png)
|
||||
local color, alpha, depth = png.color_type.color, png.color_type.alpha, png.color_type.depth
|
||||
if color == "palette" or (color == "truecolor" and depth == 8) then
|
||||
return
|
||||
end
|
||||
for index, value in pairs(png.data) do
|
||||
if color == "grayscale" then
|
||||
local a, Y = rescale_depth(floor(value / (2^depth)), depth, 8), rescale_depth(floor(value % (2^depth)), depth, 8)
|
||||
png.data[index] = a * 0x1000000 + Y * 0x10000 + Y * 0x100 + Y -- R = G = B = Y
|
||||
else
|
||||
assert(color == "truecolor" and depth == 16)
|
||||
local r = rescale_depth(floor(value / 0x100000000), depth, 8)
|
||||
local g = rescale_depth(floor(value / 0x10000) % 0x10000, depth, 8)
|
||||
local b = rescale_depth(value % 0x10000, depth, 8)
|
||||
local a = 0xFF
|
||||
if alpha then
|
||||
a = rescale_depth(png.alpha_data[index], depth, 8)
|
||||
end
|
||||
png.data[index] = a * 0x1000000 + r * 0x10000 + g * 0x100 + b
|
||||
end
|
||||
end
|
||||
png.alpha_data = nil
|
||||
end
|
||||
|
||||
local function encode_png(width, height, data, compression, raw_write)
|
||||
local write = raw_write
|
||||
local function byte(value)
|
||||
write(char(value))
|
||||
end
|
||||
local function _uint(value)
|
||||
local div = 0x1000000
|
||||
for _ = 1, 4 do
|
||||
byte(floor(value / div) % 0x100)
|
||||
div = div / 0x100
|
||||
end
|
||||
end
|
||||
local function uint(value)
|
||||
assert(value < 2^31)
|
||||
_uint(value)
|
||||
end
|
||||
local chunk_content
|
||||
local function chunk_write(text)
|
||||
insert(chunk_content, text)
|
||||
end
|
||||
local function chunk(type)
|
||||
chunk_content = {}
|
||||
write = chunk_write
|
||||
write(type)
|
||||
end
|
||||
local function end_chunk()
|
||||
write = raw_write
|
||||
local chunk_len = 0
|
||||
for i = 2, #chunk_content do
|
||||
chunk_len = chunk_len + #chunk_content[i]
|
||||
end
|
||||
uint(chunk_len)
|
||||
write(concat(chunk_content))
|
||||
local chunk_crc = 0xFFFFFFFF
|
||||
for _, text in ipairs(chunk_content) do
|
||||
chunk_crc = update_crc(chunk_crc, text)
|
||||
end
|
||||
_uint(bit_xor(chunk_crc, 0xFFFFFFFF))
|
||||
end
|
||||
-- Signature
|
||||
write(signature)
|
||||
chunk"IHDR"
|
||||
uint(width)
|
||||
uint(height)
|
||||
-- Always use bit depth 8
|
||||
byte(8)
|
||||
-- Always use color type "truecolor with alpha"
|
||||
byte(6)
|
||||
-- Compression method: deflate
|
||||
byte(0)
|
||||
-- Filter method: PNG filters
|
||||
byte(0)
|
||||
-- No interlace
|
||||
byte(0)
|
||||
end_chunk()
|
||||
chunk"IDAT"
|
||||
local data_rope = {}
|
||||
for y = 0, height - 1 do
|
||||
local base_index = y * width
|
||||
insert(data_rope, "\0")
|
||||
for x = 1, width do
|
||||
local colorspec = modlib.minetest.colorspec.from_any(data[base_index + x])
|
||||
insert(data_rope, char(colorspec.r, colorspec.g, colorspec.b, colorspec.a))
|
||||
end
|
||||
end
|
||||
write(minetest.compress(type(data) == "string" and data or concat(data_rope), "deflate", compression))
|
||||
end_chunk()
|
||||
chunk"IEND"
|
||||
end_chunk()
|
||||
end
|
||||
|
||||
(...).encode_png = minetest.encode_png or function(width, height, data, compression)
|
||||
local rope = {}
|
||||
encode_png(width, height, data, compression or 9, function(text)
|
||||
insert(rope, text)
|
||||
end)
|
||||
return concat(rope)
|
||||
end
|
||||
Loading…
Reference in New Issue
Block a user