UnityGLTF插件加载模型时，emissiveFactor解析报错

项目中遇到使用 UnityGLTF插件加载GLTF模型时报错，如下图：

 根据报错信息，我们找到GLTF文件中，第[五]个材质的描述：

    {
      "name": "11_-_Default木质长廊1.bmp_alpha",
      "occlusionTexture": {
        "index": 0,
        "texCoord": 1
      },
      "pbrMetallicRoughness": {
        "baseColorFactor": [
          0.8470589,
          0.43921572,
          0.0,
          0.7
        ],
        "metallicFactor": 0.099999994,
        "roughnessFactor": 1
      },
      "alphaMode": "BLEND",
      "emissiveFactor": [
        0.799999952,
        0.799999952,
        0.799999952,
        1.0
      ]
    }

其中emissiveFactor的值是：

            "emissiveFactor": [
                0.799999952,
                0.799999952,
                0.799999952,
                1
            ]

然后，我们再看一下插件源码：

        public static Color ReadAsRGBColor(this JsonReader reader)
        {
            if (reader.Read() && reader.TokenType != JsonToken.StartArray)
            {
                throw new Exception(string.Format("Invalid vector value at: {0}", reader.Path));
            }

            var color = new Color
            {
                R = (float) reader.ReadAsDouble().Value,
                G = (float) reader.ReadAsDouble().Value,
                B = (float) reader.ReadAsDouble().Value,
                A = 1.0f
            };

            if (reader.Read() && reader.TokenType != JsonToken.EndArray)
            {
                throw new Exception(string.Format("Invalid color value at: {0}", reader.Path));
            }

            return color;
        }

可以看到Alpha直接用1.0f赋值，又由于emissiveFactor中有四个分量，就会导致下一个if中的

reader.TokenType != JsonToken.EndArray 是成立的，所以就抛出了异常

修改后的代码：

        public static Color ReadAsRGBColor(this JsonReader reader)
        {
            if (reader.Read() && reader.TokenType != JsonToken.StartArray)
            {
                throw new Exception(string.Format("Invalid vector value at: {0}", reader.Path));
            }

            var channels = new float[4] { 1f, 1f, 1f, 1f };

            for (int i = 0; i < 4; i++)
            {
                var readObject = reader.ReadAsDouble();
                if (reader.TokenType == JsonToken.EndArray)
                {
                    UnityEngine.Debug.LogError(string.Format("Irregular color value at: {0}", reader.Path));
                    break;
                }
                if (readObject.HasValue)
                {
                    channels[i] = (float)readObject.Value;
                }
            }

            if (reader.TokenType != JsonToken.EndArray && reader.Read() && reader.TokenType != JsonToken.EndArray)
            {
                throw new Exception(string.Format("Invalid color value at: {0}", reader.Path));
            }

            var color = new Color
            {
                R = channels[0],
                G = channels[1],
                B = channels[2],
                A = channels[3]
            };

            return color;
        }