GenericCAO models are dark when below y = 0

[paramat]

Testing on a local server:

Jumping or hovering slightly above a node makes light return, so i suspect that the recent 'player settable collisionbox' change has shifted the point that defines player model light down by a node to feet position, and that being below y = 0 is a sign reversal that puts that point just inside the node below.
If so then when above y = 0, flying very slightly into the ground should make the player go dark too:

Confirmed. So it seems that a 1-node vertical offset was forgotten somewhere.
@TeTpaAka

[paramat]

I might know why. Previously player pos was centre of model, now it's foot position, so light is being sampled at foot position, we need to add in a vertical offset to raise this point back up to model centre, or, up by 1 node. If we raise by 0.9 * BS this will be rough model centre. But only for player objects.

[paramat]

https://github.com/minetest/minetest/blob/master/src/content_cao.cpp#L944

v3s16 GenericCAO::getLightPosition()
{
	return floatToInt(m_position, BS);
}

Compare to items:

v3s16 ItemCAO::getLightPosition()
{
	return floatToInt(m_position + v3f(0,0.5*BS,0), BS);
}

But i'm concerned about any added offset being applied to all CAOs instead of just players.

[kaadmy]

Just so you know, ItemCAO doesn't seem used outside of content_cao.cpp.

[kaadmy]

Doesn't the player have a seperate subclass of GenericCAO?

[nerzhul]

if i remember ItemCAO is obsolete

[paramat]

Ok.
Fot genericCAO i think it's best to go with
return floatToInt(m_position + v3f(0, 0.5 * BS, 0), BS);
to work with mobs / players that are 1 node high, this is also halfway up a node height so is a good general light position, i'll make a PR.

[Wuzzy2]

This is not just for player models, but for any models. I have seen this for item entities, boats, carts, mobs and pretty much any entity based on a mesh.

[paramat]

Yes but that's different and a non-issue, that usually happens when the model centre passes into a node, the model centre being the point that determines where light is sampled.
This issue is player model going dark when correctly standing on a node, because the light position is at foot level instead of higher up.

[bigfoot547]

I also noticed that the nametag is not on top of the player, but rather in the center of the player.

[TeTpaAka]

@paramat No, it is the same issues. Now, players, mobs and other entities use the same code for display and so they (should) show the same behavior. If a mob would be standing at the exact same position like the player in your screenshot, it would be black. The client doesn't even differentiate between other players and luaentities.

@bigfoot547 I'll look into it.

[paramat]

Ok, i thought people were describing the existing behaviour. Obviously mobs should have the same issue.

[SmallJoker]

#6179 merged.

[paramat]

It wasn't merged, just done it now.