Add support for glMapBufferRange. Use glMapBufferRange and glMapBufferSubData.

src/gpu/gl/debug/GrBufferObj.h

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrBufferObj_DEFINED
 #define GrBufferObj_DEFINED
@@ skipping 16 matching lines @@
     }
     virtual ~GrBufferObj() {
         delete[] fDataPtr;
     }
 
     void access() {
         // cannot access the buffer if it is currently mapped
         GrAlwaysAssert(!fMapped);
     }
 
-    void setMapped()             { fMapped = true; }
+    void setMapped(GrGLintptr offset, GrGLsizeiptr length) {
+        fMapped = true;
+        fMappedOffset = offset;
+        fMappedLength = length;
+    }
     void resetMapped()           { fMapped = false; }
     bool getMapped() const       { return fMapped; }
+    GrGLsizei getMappedOffset() const { return fMappedOffset; }
+    GrGLsizei getMappedLength() const { return fMappedLength; }
 
     void setBound()              { fBound = true; }
     void resetBound()            { fBound = false; }
     bool getBound() const        { return fBound; }
 
     void allocate(GrGLsizeiptr size, const GrGLchar *dataPtr);
     GrGLsizeiptr getSize() const { return fSize; }
     GrGLchar *getDataPtr()       { return fDataPtr; }
 
     void setUsage(GrGLint usage) { fUsage = usage; }
     GrGLint getUsage() const     { return fUsage; }
 
     virtual void deleteAction() SK_OVERRIDE;
 
 protected:
 private:
 
     GrGLchar*    fDataPtr;
-    bool         fMapped;       // is the buffer object mapped via "glMapBuffer"?
+    bool         fMapped;       // is the buffer object mapped via "glMapBuffer[Range]"?
+    GrGLintptr   fMappedOffset; // the offset of the buffer range that is mapped
+    GrGLsizeiptr fMappedLength; // the size of the buffer range that is mapped
     bool         fBound;        // is the buffer object bound via "glBindBuffer"?
     GrGLsizeiptr fSize;         // size in bytes
     GrGLint      fUsage;        // one of: GL_STREAM_DRAW,
                                 //         GL_STATIC_DRAW,
                                 //         GL_DYNAMIC_DRAW
 
     typedef GrFakeRefObj INHERITED;
 };
 
 #endif // GrBufferObj_DEFINED