Is it possible to fill in vector graphics?

Is there a way to fill in something like this bird shape?
It is currently drawn using line().

vector_bird

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vector_bird

by Doriencey

Cart #vector_bird-0 | 2024-06-01 | Code ▽ | Embed ▽ | No License

1

Once you've drawn it you can pick a random point inside the shape and do a flood fill.

Here's an explanation of the flood fill algorithm if you're not familiar with it: https://www.youtube.com/watch?v=ldqAmkdthHY

User scgrn wrote a function that does exactly what you want.
https://www.lexaloffle.com/bbs/?tid=28312

@RealShadowCaster that is exactly what I was looking for. Thanks
@jasondelaat Isn't floodfill too slow? I haven't tried it, so I am not sure, but it sounds like I would need a lot of pset operations each frame.

I made VECTOR_FILL for reference.

This code is not intended to be so efficient in logic.
If the drawing coordinates are out of range or the figure is large, it will be out of memory.

vectorfill_ps

by shiftalow

Cart #vectorfill_ps-1 | 2024-06-03 | Code ▽ | Embed ▽ | No License

1

function fillvector(x,y,p)
    local d={1,0,-1,0,1}
    local i=2
    while pget(x,y)~=p do
        pset(x,y,p)
        while d[i] do
            fillvector(x+d[i-1],y+d[i],p)
            i+=1
        end
    end
end

you are right - floodfill is rarely what you want (terribly slow).

you should:

• split your shape into triangles
• use p01 (or shiftallow) trifill from https://www.lexaloffle.com/bbs/?tid=31478

"Isn't floodfill too slow?"

Oh yeah, for sure. I mean it depends on what you want I guess. If you're just drawing the image statically on screen and nothing else then it doesn't really matter but if you're animating or resizing it or whatever then yeah, floodfill is not your friend. I thought you were just looking for any way to fill it so I went with simple over efficient.

@jasondelaat, I for once like your fillvector, especially how the 4 2D unit vectors are stored in a single array 1D array.
I'm wondering though, why

while pget(x,y)~=p do

instead of

if pget(x,y)~=p then

?

@RealShadowCaster, that's actually @shiftalow's code not mine. I agree though, seems like it should be if instead of while since the loop will run at most once anyway.

@RealShadowCaster

Judging from the content, is this probably a reply to me?
Thank you.

2D reference of 1D array is an interesting method, but it doesn't seem to be very efficient here.
Also, there is no deep meaning behind the pget() check in while. (It's fine to use if)

And, since FILLVECTOR is probably commonly called FLOODFILL, I'll post the correction below.

Fixed version

function floodfill(x,y,p)
    if pget(x,y)~=p then
        pset(x,y,p)
        floodfill(x+1,y,p)
        floodfill(x,y+1,p)
        floodfill(x-1,y,p)
        floodfill(x,y-1,p)
    end
end

Even faster (more complicated) version

function floodfill(x,y,p)
    if pget(x,y)~=p then
        pset(x,y,p)
        return floodfill(x-1,y,floodfill(x+1,y,floodfill(x,y-1,floodfill(x,y+1,p))))
    end
    return p
end