[F] Get return "like true" when error occured.

code/glTF2Exporter.cpp

@@ -514,9 +514,9 @@ void glTF2Exporter::ExportMaterials()
             GetMatColor(mat, pbrSG.specularFactor, AI_MATKEY_COLOR_SPECULAR);
 
             if (mat->Get(AI_MATKEY_GLTF_PBRSPECULARGLOSSINESS_GLOSSINESS_FACTOR, pbrSG.glossinessFactor) != AI_SUCCESS) {
-                float shininess;
+				float shininess;
 
-                if (mat->Get(AI_MATKEY_SHININESS, shininess)) {
+				if (mat->Get(AI_MATKEY_SHININESS, shininess) == AI_SUCCESS) {
                     pbrSG.glossinessFactor = shininess / 1000;
                 }
             }