medical: Don't divide by zero

[dastrukar]

Just adds a check to see if width is 0 or not.
Also, I'm not sure if this is the best/cleanest way to implement this check, but oh well.

[caligari87]

I usually prefer some variation on min(), max(), or clamp() because I have a hard time parsing ternaries at a glance. I think the latter is also more expensive because it's a branching instruction? Could be wrong on that and it may or may not make a difference here anyway.

If you felt like rewriting that part thusly, it would be nice. But if not, or there's no way to do it cleanly, then this is fine and you can merge at your convenience.

[dastrukar]

So far, the only other two I can come up with is this:

		if (width > 0.) { BP.StartAlpha = min(1, max((depth / width), 0.3)); }
		else { BP.StartAlpha = 0.3; }

and this

		BP.StartAlpha = min(1, max(depth / (width + 0.00001), 0.3));

[dastrukar]

Changed it to the "if else" check, since that probably makes more sense than the "add 0.00001 to prevent div by zero" and also more readable than the ternary thing.