This is my code snippet for 8-dir movement in PICO-8. There are some in BBS like this but I think I have something to add here because:
1 - It doesn't move faster when going diagonals;
2 - It can move at speeds below 1 pixel/frame (sub-pixel movement);
3 - And most importantly: IT DOESN'T HAVE ANY ANNOYING JITTERING (the staircase effect)!!!
Feel free to scrutinize my code and give me any constructive tips. I am still getting started with PICO-8 and Lua.
10 comments
Do anyone know how constant is the duration of a frame in PICO-8?
I am considering making samething that will use rhythm and decided to use the frames as a time basis. First thing I implemented was a simple metronome.
Code below:
This function rounds a number n to the nearest integer that is multiple of m:
function round_mult(n, m)
-- n is the number to be
-- rounded.
-- m is the integer
-- significance.
-- returns the nearest
-- multiple of m.
if (n % m) == 0 then
return n
else
v_up = flr(n) + 1
v_up = n + (m - n % m)
v_dn = flr(n)
v_dn = n - (n % m)
if (v_up - n) <= (n - v_dn) then
return v_up
else
return v_dn
end
end
end
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On the metronome itself, I want to put a bpm and use the nearest bpm that can fit inside a frame time.
function _init()
bpm = 50 -- this is not necessarily the actual bpm ingame.
btime = 60/bpm -- time per beat in seconds
subdivs = 4 -- subdivisions of a beat
fps = stat(7) -- framerate
ftime = 1/fps -- time per frame
bframes = round_mult(
btime / ftime,
subdivs) -- the actual bpm to be used, but in frames instead of seconds
curframe = 1 -- frame count starts at 1
end
function _update()
if curframe == bframes then
sfx(1) -- this is the end of a beat
curframe = 1
elseif (curframe
% (bframes / subdivs))
== 0 then
sfx(0) -- this is a subdivision of a beat
curframe = curframe + 1
else
curframe = curframe + 1
end
end
function _draw()
cls()
print(tostr(curframe))
end
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The thing is, I recorded the beeps and I noticed (using audacity) that the times of the beats are not always the same. It differs a little bit. Can frames take slightly longer or shorter times to occur inside PICO-8?
