toJSON(obj) {
        var json = BaseSerializer.prototype.toJSON.call(this, obj);

        json.depthBuffer = obj.depthBuffer;
        json.depthTexture = !obj.depthTexture ? null : new TexturesSerializer().toJSON(obj.depthTexture);
        json.height = obj.height;
        json.scissor = obj.scissor;
        json.scissorTest = obj.scissorTest;
        json.stencilBuffer = obj.stencilBuffer;
        json.texture = !obj.texture ? null : new TexturesSerializer().toJSON(obj.texture);
        json.viewport = obj.viewport;
        json.width = obj.width;
        json.isWebGLRenderTarget = obj.isWebGLRenderTarget;

        return json;
    }
WebGLRenderTargetSerializer
@author tengge / https://github.com/tengge1