bugfix(shadow): Fix missing tree shadow decals when no object shadow decals exist

[xezon]

• Fixes Blob shadows pop in #261

This change fixes the missing tree shadow decals while no object shadow decals exist.

The issue happens because the decal draw bounds are only updated when there are object decal shadows (for example under infantry units).

Original

Map: North America

This change

TODO

• Replicated in Generals

[xezon]

I moved these into the class.

[xezon]

This change does not exactly relate to the fix, but is related to tree shadows. Essentially Y was flipped which should flip the texture, but that does not make a difference because the decal shadow is a dark circle and inconsequential to flipping.

[Mauller]

Looks Shady to me

[xezon]

While replicating to Generals, I noticed that this issue does not happen in Generals, because Trees are not rendered through the W3DTreeBuffer. Looks like it was WIP from Generals to Zero Hour development and did not make the cut.

W3DTreeBuffer::W3DTreeBuffer(void)
{
	m_initialized = false;
	///@toto - reactivate this optimization if useful.  jba.
	return;
...

I replicated what can be replicated anyway and user facing it will change nothing in Generals.

[Mauller]

While replicating to Generals, I noticed that this issue does not happen in Generals, because Trees are not rendered through the W3DTreeBuffer. Looks like it was WIP from Generals to Zero Hour development and did not make the cut.

W3DTreeBuffer::W3DTreeBuffer(void)
{
	m_initialized = false;
	///@toto - reactivate this optimization if useful.  jba.
	return;
...

I replicated what can be replicated anyway and user facing it will change nothing in Generals.

When decoupling the tree sway from the render FPS i also noticed something similar.
The sway is implemented and handled in the tree buffer in zero hour.