Artwork creation during tick fails if index_offset zero

[Chadnaut]

Appears to be a bug since other offsets work (also occurs in AM vanilla)

local a, b, c;

function on_tick(tick_time) {
    if (!a) {
        a = fe.add_artwork("snap", 110, 0, 100, 100);
        a.index_offset = 0; // zero doesn't work?
    }
    if (!b) {
        b = fe.add_artwork("snap", 220, 0, 100, 100);
        b.rawset_index_offset(-1); // rawset to a different offset...
        b.index_offset = 0; // ...then set zero, works
    }
    if (!c) {
        c = fe.add_artwork("snap", 330, 0, 100, 100);
        c.index_offset = 1; // non-zero always works
    }
}

fe.add_artwork("snap", 0, 0, 100, 100);
fe.add_ticks_callback("on_tick");

[oomek]

There are many reasons why drawables should not be added in tick, but I believe you know what you are doing and there is no way to achieve what you need when drawables are added in transitions or in the main layout body.
I've checked the code and AM+ behaviour is consistent with AM 2.7.0, same bug. It is even worse with Vid.ImagesOnly flag. a,b,c don't show up at all until you navigate.
To be honest it's not what I would jump onto and investigate immediately, but will keep this issue open until I finish the new transition model.

[Chadnaut]

I have a create/animate/update pipeline that runs on tick (no leaks).
video_flags does work, but only if it's set before index_offset.
The rawset workaround does the job, so this quirk is not a show-stopper.

[oomek]

Easy fix by commenting

attractplus/src/fe_image.cpp

Line 672 in 6b2fec5

if ( m_index_offset != io )

But if the index_offset is set on each tick it will be a performance hog.
Still trying to figure out a solution for this.