updated doc on common interfaces of features2d; added some method for GenericDescriptorMatcher

modules/features2d/include/opencv2/features2d/features2d.hpp

@@ -2059,6 +2059,8 @@ public:
 
     virtual void train() = 0;
 
+    virtual bool supportMask() = 0;
+
     /*
      * Classifies query keypoints.
      * queryImage    The query image
@@ -2202,6 +2204,8 @@ public:
 
     virtual void train();
 
+    virtual bool supportMask() { return false; }
+
     // Reads match object from a file node
     virtual void read( const FileNode &fn );
     
@@ -2271,6 +2275,8 @@ public:
 
     virtual void train();
 
+    virtual bool supportMask() { return false; }
+
     virtual void read( const FileNode &fn );
     virtual void write( FileStorage& fs ) const;
     
@@ -2319,6 +2325,8 @@ public:
 
     virtual void train();
 
+    virtual bool supportMask() { matcher->supportMask(); }
+
     virtual void read( const FileNode& fn );
     virtual void write( FileStorage& fs ) const;