:truck: new directive `set_attenuation_defaults`

[ohlidalp]

Works like all other set_*_defaults directives. The arguments are an exact match to the Ogre::Light::setAttenuation(), see https://ogrecave.github.io/ogre/api/latest/class_ogre_1_1_light.html#a43f763d809bc7da9a85fec15f57380f4

Only affects flares3 for the moment.

Parameters:

• range The absolute upper range of the light in world units.
• constant The constant factor in the attenuation formula: 1.0 means never attenuate, 0.0 is complete attenuation.
• linear The linear factor in the attenuation formula: 1 means attenuate evenly over the distance.
• quadratic The quadratic factor in the attenuation formula: adds a curvature to the attenuation formula.

I thoroughly verified using debugger that the values do propagate to the OGRE light source and stay there. I wasn't able to see any effect though. Let's test under OGRE 14.

My testing vehicle: flare3attenuation-agoras.zip

[ohlidalp]

Closing until migration to OGRE14, then this becomes relevant.