[Vanilla Bug] Turrets and barrels do not cast a shadow

[Crimsonum]

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I have attached as much information as possible (screenshots, debug and exception logs, etc).

Description

The game engine does not draw shadows for turrets (or barrels). It does not matter whether the parent object is a building or unit, shape or voxel. If it's a shape, the game expects turret shadow frames to be present in the shape file, but does not actually draw them.

There is an obsolete art INI key for vehicle shapes with a comment that states the following:

UseTurretShadow=<bool> ; use the turret of the object to cast shadow (def=no)?

It could be worth fixing/reimplementing this toggle, and have it on by default if the object has a turret, and disabled otherwise.

Required Code (optional)

No response

Steps To Reproduce

Observe the shadow of an object with a turret and/or barrel. Note that in the vanilla game, all shape objects with turrets have blank turret shadow frames, so the problem cannot be readily observed with vanilla graphics for shapes, only voxels.

Expected Behaviour

Turret shadow frames should be drawn. Voxel turrets (and barrels) should cast a shadow as does the body.

Actual Behaviour

Turret shadow frames are not drawn. In case of voxels, only the body casts a shadow, and only one section in the body, in case there are multiple (see ShadowIndex).

Additional Context

• Top-Left: Hover MLRS (voxel). Note the lack of shadow for the missile pods (turret).
• Bottom-Left: Titan (shape). Note the lack of shadow for the turret.
• Right: An example of how the Titan turret's shadow should look like.