build.lua

#!/usr/bin/env lua

--------------
-- Settings --
--------------

-- Set this to true to use a better compression algorithm for the sound driver.
-- Having this set to false will use an inferior compression algorithm that
-- results in an accurate ROM being produced.
local improved_sound_driver_compression = false

---------------------
-- End of settings --
---------------------

local common = require "build_tools.lua.common"

local exit_code
local repository = "https://github.com/sonicretro/s2disasm"

local function success_continue_wrapper(success, continue)
	if not success then
		exit_code = false
	end

	if not continue then
		os.exit(false)
	end
end

-- Obtain the paths to the native build tools for the current platform.
local tools, platform_directory = common.find_tools("build tool bundle", "build_tools/source_code/", repository, "fixpointer", "saxman")

-- Present an error message to the user if the build tools for their platform do not exist.
if tools == nil then
	common.show_flashy_message("Build failed. See above for more details.")
	os.exit(false)
end

-- Begin the insane task of assembling and compressing Sonic 2's music...

local clownmd5 = require "build_tools.lua.clownmd5"

-- 'hashes.lua' contains the hashes of every assembled song. If a song's hash
-- matches the one recorded in this file, then there is no need to assemble it again.
-- Our first task is to load the hashes contained in this file into a table.
local hashes_file

hashes_file = io.open("sound/music/compressed/hashes.lua", "r")

local previous_hashes

if not hashes_file then
	-- 'hashes.lua' does not exist: create an empty table instead.
	previous_hashes = {}
else
	-- 'hashes.lua' does exist: turn it into a valid Lua chunk and load its data into the table.
	local chunk = load("return {" .. hashes_file:read("a") .. "}")
	hashes_file:close()

	-- If `hash.lua` fails to compile, then ignore it and load an empty table instead.
	previous_hashes = chunk and chunk() or {}
end

-- Now that that's done, we can begin re-writing 'hashes.lua' with the new hashes that we compute in the next step.
hashes_file = io.open("sound/music/compressed/hashes.lua", "w")

hashes_file:write("improved_sound_driver_compression = " .. tostring(improved_sound_driver_compression) .. ",\n")

-- Compress the songs.
-- The songs to compress are listed in 'list of compressed songs.txt'.
for song_name in io.lines("sound/music/compressed/list of compressed songs.txt") do
	-- Determine the hash of the current song.
	local current_hash = clownmd5.HashFile("sound/music/" .. song_name .. ".asm")

	-- Finally, check if the hash matches the one in 'hashes.lua'.
	-- If it doesn't match, then the song has been modified and needs to be reassembled.
	-- Alternatively, the song will need reassembling if the user has changed the compression.
	-- Or reassemble the song if the assembled version is missing.
	if current_hash ~= previous_hashes[song_name] or improved_sound_driver_compression ~= previous_hashes.improved_sound_driver_compression or not common.file_exists("sound/music/compressed/" .. song_name .. ".bin") then
		print("Reassembling song '" .. song_name .. ".asm'...")

		-- To begin with, we'll create a wrapper ASM file to set the environment
		-- in which to assemble the lone song file. Notably, this environment
		-- includes SMPS2ASM and begins the song at address 0x1380 (the address
		-- of the Saxman decompression buffer in Z80 RAM).
		local song_file = io.open("song.asm", "w")

		song_file:write(string.format([[
	CPU 68000
	padding off

z80_ptr function x,(x)<<8&$FF00|(x)>>8&$00FF

SonicDriverVer = 2
	include "sound/_smps2asm_inc.asm"

	phase $1380
	include "sound/music/%s.asm"
	dephase

	if *>$7C0
		error "This song is too big and will overflow the decompression buffer! It should be uncompressed instead!"
	endif]], song_name))

		song_file:close()

		-- Assemble the song to an uncompressed binary.
		local success, continue = common.assemble_file("song.asm", "song.bin", "", "", false, repository)

		-- We can get rid of this wrapper ASM file now.
		os.remove("song.asm")

		success_continue_wrapper(success, continue)

		-- Now that we have an assembled song binary, compress it.
		os.execute(tools.saxman .. " " .. (improved_sound_driver_compression and "" or "-a") .. " song.bin \"sound/music/compressed/" .. song_name .. ".bin\"")

		-- Remove junk files from the assembly process.
		os.remove("song.lst")
		os.remove("song.bin")
	end

	-- Write this hash to 'hashes.lua'.
	hashes_file:write("['" .. song_name .. "'] = '")

	local function hash_string_iterator()
		local position = 1

		return function()
				if position > current_hash:len() then
					return nil
				end

				local byte
				byte, position = string.unpack("I1", current_hash, position)

				return byte
			end
	end

	for byte in hash_string_iterator() do
		hashes_file:write(string.format("\\x%02X", byte))
	end

	hashes_file:write("',\n")
end

-- We've written the last part of the 'hashes.lua' file, so we can close it now.
hashes_file:close()

-- Huzzah: we are done with assembling and compressing the music.
-- We can move onto building the rest of the ROM.

success_continue_wrapper(common.build_rom("s2", "s2built", "", "-p=0 -z=0," .. (improved_sound_driver_compression and "saxman-optimised" or "saxman") .. ",Size_of_Snd_driver_guess,after", true, true, repository))

-- Correct some pointers and other data that we couldn't until after the ROM had been assembled.
os.execute(tools.fixpointer .. " s2.h s2built.bin   off_3A294 MapRUnc_Sonic 0x2D 0 4   word_728C_user Obj5F_MapUnc_7240 2 2 1")

-- Remove the header file, since we no longer need it.
os.remove("s2.h")

-- A successful build; we can quit now.
os.exit(exit_code)