Thick line drawing routine (as a reply to @JadeLombax Twitter).
Manual:
linefill x0 y0 x1 y1 r [col] draw a 2*r pixel wide line note: r must be >= 0.5 to produce meaningful results note: the code uses sub-pixel precision rasterization, allowing smooth movement |
Example:
-- 4 pixel wide white line linefill(45,34,67,96,2,7) |
Looks nice, I'll have to try and figure out how it works. You said this is a reply to something from me on Twitter?
The code is neat, the only "issue" I had is that I can't find a combination of values where the thick line and a circfill can agree on the same size. Besides that, it's perfect.
not a surprise - I don’t use the same rounding as native pico8 functions.
if you want an exact match, strip the ‘sub-pixel’ part from my code.
(but at the cost of a lot more pixel jerkiness)
That's why I placed "issue" it in quotes :)
I tinkered aground with it a bit, and found something that n should work well for the idea I have in mind.
the linefill code can be easily extended to draw arbitrary convex polygons. You can draw joints with the same pixel rules
Thanks for this. I realised I needed a thick line routine and this is perfect.
about 5 years late to this thread lol
mainly did this to practice token reduction, but i got bored and managed to reduce the token count of this routine by 52 (265 to 213)
the function works the exact same with a few optimizations, some fast math, and a removal of the if(d<0.001) return statement, since i have yet to notice any problems without it.
function linefill(ax, ay, bx, by, r, c)
if (c) color(c)
-- modify bx, by directly
bx, by = bx - ax, by - ay
-- more token-efficient distance calculation: https://www.lexaloffle.com/bbs/?pid=168322#p
local s = sin(atan2(bx, by))
local d = abs(s == 0 and bx or by / s)
local ca, sa, spans = bx / d, -by / d, {}
local x0, y0 = ax + r * sa, ay + r * ca
for i = 1, 4 do
-- s table removed in favor of calculating u and v in the loop itself
local u, v = i % 3 ~= 1 and d or 0, r * sgn(i - 3)
local x1, y1 = ax + u * ca + v * sa, ay - u * sa + v * ca
local _x1, _y1 = x1, y1
if (y0 > y1) x0, y0, x1, y1 = x1, y1, x0, y0
local dx = (x1 - x0) / (y1 - y0)
if (y0 < 0) x0 -= y0 * dx y0 = -1
local a = y0 \ 1 + 1
-- sub-pix shift
x0 += (a - y0) * dx
for y = a, min(y1 \ 1, 127) do
-- open span?
local span = spans[y]
if (span) rectfill(x0, y, span, y) else spans[y] = x0
x0 += dx
end
x0, y0 = _x1, _y1
end
end |
this isn't me trying to one-up you or anything, i was just a bit bored :P really nice function overall!
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