Rip textures from a quake1 bsp. Requires the palette.lmp file with the quake palette.

textool.rb

require 'chunky_png'

Texture = Struct.new(:name, :width, :height, :pixels)
TextureLump = Struct.new(:count, :offsets)
textures = []

bsp = IO.read(ARGV.first, mode: "rb")
palette = IO.read("palette.lmp", mode: "rb")

tex_lump_offset = bsp[20, 4].unpack("L").first

tex_lump = TextureLump.new
tex_lump.count = bsp[tex_lump_offset, 4].unpack("L").first
tex_lump.offsets = []

#Collect offsets to textures
(0...tex_lump.count).each do |i|
    index = tex_lump_offset + 4 + (i * 4)
    tex_lump.offsets[i] = bsp[index, 4].unpack("L").first
end

#Collect texture data
(0...tex_lump.count).each do |i|
    offset = tex_lump_offset + tex_lump.offsets[i]
    tex = Texture.new
    tex.name = bsp[offset, 16]
    tex.width = bsp[offset + 16, 4].unpack("L").first
    tex.height = bsp[offset + 20, 4].unpack("L").first
    tex_size = tex.width * tex.height
    colors = bsp[offset + 40, tex_size].unpack("C*")
    tex.pixels = []
    colors.each do |color|
        tex.pixels.push(palette[color*3, 3].unpack("C*"))
    end
    tex.pixels = tex.pixels.flatten
    textures.push(tex)
end

textures.each do |tex|
        png = ChunkyPNG::Image.new(tex.width, tex.height)
        (0...tex.height).each do |y|
            (0...tex.width).each do |x|
                index = ((y * tex.width) + x) * 3
                png.set_pixel(x, y, ChunkyPNG::Color.rgb(tex.pixels[index], tex.pixels[index+1], tex.pixels[index+2]))
            end
        end
        png.save(tex.name[0...tex.name.index("\0")].gsub('*','') + ".png", :fast_rgb)
end