Mesen2/MesenCE Lua Script: FDS Wavetable Snooper

FDSWaveSnooper.lua

-----------------------
-- Name: FDS Wavetable Snooper
-- Author: TakuikaNinja
-----------------------
-- Snoops FDS wavetable RAM writes for ripping purposes.
-- Right mouse click toggles linear interpolation between points.
-- Log format is compatible with FamiTracker (0-63, space separator).
-----------------------

local consoleType = emu.getState()["consoleType"]
if consoleType ~= "Nes" then
	emu.displayMessage("Script", "This script only works on the NES/FC.")
	return
end

hold_button = false
line_mode = true

write_enable = false
wave_ram = {}
-- sensible programs should be writing to all entries...
for i = 1, 64 do
	wave_ram[i] = 0
end

function checkWriteEnable(address, value)
	if (value & 0x80) > 0 then
		write_enable = true
	elseif write_enable then
		-- newly disabled writes likely means the program finished writing
		-- output the current wave RAM state
		write_enable = false
		emu.log(table.concat(wave_ram, " ") .. " ") -- extra space just to make copying easier
	end
end

function waveWrite(address, value)
	if write_enable then
		wave_ram[address - 0x403F] = value & 63
	end
end

function displayWave()
	local BOX_X = 128 - 33
	local BOX_Y = 4
	local SIZE = 64 + 2
	local BOX_COLOUR = 0x00FF00
	local WAVE_COLOUR = 0xFF0000
	
	if emu.getMouseState().right then
		if not hold_button then
			line_mode = not line_mode
			hold_button = true
		end
	else
		hold_button = false
	end
	
	emu.drawRectangle(BOX_X, BOX_Y, SIZE, SIZE, 0x80808080, true)
	emu.drawRectangle(BOX_X, BOX_Y, SIZE, SIZE, BOX_COLOUR, false)
	
	for i = 1, #wave_ram do
		local y = 64 - wave_ram[i]
		-- linear interpolation
		if line_mode and i > 1 then
			local prev_y = 64 - wave_ram[i-1]
			emu.drawLine(BOX_X + i - 1, BOX_Y + prev_y, BOX_X + i, BOX_Y + y, WAVE_COLOUR | 0xC0000000)
		end
		emu.drawPixel(BOX_X + i, BOX_Y + y, WAVE_COLOUR)
	end
end

script = "FDS Wavetable Snooper"
emu.displayMessage("Script", script)

emu.addMemoryCallback(checkWriteEnable, emu.callbackType.write, 0x4089)
emu.addMemoryCallback(waveWrite, emu.callbackType.write, 0x4040, 0x407F)
emu.addEventCallback(displayWave, emu.eventType.startFrame)