copy method
Implementation
@override
MeshToonMaterial copy(Material source) {
super.copy(source);
color.copy(source.color);
map = source.map;
gradientMap = source.gradientMap;
lightMap = source.lightMap;
lightMapIntensity = source.lightMapIntensity;
aoMap = source.aoMap;
aoMapIntensity = source.aoMapIntensity;
emissive?.copy(source.emissive!);
emissiveMap = source.emissiveMap;
emissiveIntensity = source.emissiveIntensity;
bumpMap = source.bumpMap;
bumpScale = source.bumpScale;
normalMap = source.normalMap;
normalMapType = source.normalMapType;
normalScale?.copy(source.normalScale!);
displacementMap = source.displacementMap;
displacementScale = source.displacementScale;
displacementBias = source.displacementBias;
alphaMap = source.alphaMap;
wireframe = source.wireframe;
wireframeLinewidth = source.wireframeLinewidth;
wireframeLinecap = source.wireframeLinecap;
wireframeLinejoin = source.wireframeLinejoin;
fog = source.fog;
return this;
}