copy method
Copy the parameters from the passed material into this material.
Implementation
@override
PointsMaterial copy(Material source) {
super.copy(source);
color.setFrom(source.color);
map = source.map;
alphaMap = source.alphaMap;
size = source.size;
sizeAttenuation = source.sizeAttenuation;
fog = source.fog;
return this;
}