while(true)
{
call lua's beforeemulation hooks
emulate a frame
call lua's afteremulation hooks
if(displayframe)
{
call lua's graphics hooks
update screen
}
call main lua function
}
Kuwaga: The lua scripts never actually make the emulator frameadvance.
So think of frameadvance as "Ok, I'm done for now - keep going as usual"
Raijin: The snes9x/FCEU/etc tables should be (and probably have already been) deprecated in favor of the "emu" table. One reason for this is that a sufficiently generic script should work with any emulator without need of modification. Having to globally change "snes9x" to "FCEU" to make a script work on another platform isn't exactly onerous, but it is undesirable just the same.
I've been looking at the sample lua scripts to get an idea of how to write it (I really see how I can use this in some of my future projects) Its nothing too different from Java or C++. However, some parts of it seem fuzzy for me. Just to be sure I get the basics of it, how would the general syntax of these two look like (with Desmume 0.9.5 as the emulator): While a certain memory value is 0, press "right" and X Keep advancing one frame until a certain memory value is 1, then have a save state at that point.
state = savestate.create();
while true do
if memory.readbyte(0x1234) == 0 then
joypad.set(1, {"right" = true, "X" = true});
elseif memory.readbyte(0x1234) == 1 then
savestate.save(state);
emu.pause();
end;
emu.frameadvance();
end;DarkKobold: If you look at the pseudocode I posted above, you will probably see the cause of your problem. The lua main loop is called after the screen has been updated, but before the next frame has been emulated. So at this point, your script has access to the previous frame's state, but anything you draw will appear the next frame, and thus effectively lag one frame. To avoid this problem, you can use the other lua hooks. Afteremulation, for example.
-- Script runs forever
while true do
-- push button
joypad.set(1, {A = true})
snes9x.frameadvance()
-- release button
joypad.set(1, {A = false})
snes9x.frameadvance()
end
-- On/off rapid toggling of this variable
local status = true
while true do
-- Give the user an out by pressing start. This exits out of the loop
-- and since the script ends at that point, the script exits
if joypad.get(1)['start'] then
break
end
-- Press (or not) the A button. All other buttons are not pressed
-- and the user's input be damned.
joypad.set(1, {A = status})
-- Toggle toggle
status = not status
-- Next frame
snes9x.frameadvance()
end
Joypad.get()
Snes9x.frameadvance()
Joypad.set()
snes9x.frameadvance()
Snes9x.frameadvance
Joypad.get
Joypad.set
Snes9x.frameadvance