Add opacity and getOpacity() as double

Author: flarive

src/ofbx.cpp

@@ -1400,6 +1400,7 @@ struct MaterialImpl : Material
 	double getAmbientFactor() const override { return ambient_factor; };
 	double getBumpFactor() const override { return bump_factor; };
 	double getEmissiveFactor() const override { return emissive_factor; };
+	double getOpacity() const override { return opacity; };
 
 	const Texture* textures[Texture::TextureType::COUNT];
 	Color diffuse_color;
@@ -1416,6 +1417,7 @@ struct MaterialImpl : Material
 	double ambient_factor;
 	double bump_factor;
 	double emissive_factor;
+	double opacity;
  };
 
 
@@ -2699,6 +2701,10 @@ static OptionalError<Object*> parseMaterial(const Scene& scene, const Element& e
 			{
 				material->emissive_factor = (float)prop->getProperty(property_offset)->getValue().toDouble();
 			}
+			else if (prop->first_property->value == "Opacity")
+			{
+				material->opacity = (float)prop->getProperty(property_offset)->getValue().toDouble();
+			}
 		}
 		prop = prop->sibling;
 	}

src/ofbx.h

@@ -426,6 +426,7 @@ struct Material : Object
     virtual double getAmbientFactor() const = 0;
     virtual double getBumpFactor() const = 0;
     virtual double getEmissiveFactor() const = 0;
+	virtual double getOpacity() const = 0;
 
 	virtual const Texture* getTexture(Texture::TextureType type) const = 0;
 };