diff --git a/src/OpenGL/libGLESv2/Buffer.cpp b/src/OpenGL/libGLESv2/Buffer.cpp
index 5fb1c6b..b162a5f 100644
--- a/src/OpenGL/libGLESv2/Buffer.cpp
+++ b/src/OpenGL/libGLESv2/Buffer.cpp
@@ -27,6 +27,10 @@
     mContents = 0;
     mSize = 0;
     mUsage = GL_DYNAMIC_DRAW;
+	mIsMapped = false;
+	mOffset = 0;
+	mLength = 0;
+	mAccess = 0;
 }
 
 Buffer::~Buffer()
@@ -75,6 +79,33 @@
 	}
 }
 
+void* Buffer::mapRange(GLintptr offset, GLsizeiptr length, GLbitfield access)
+{
+	if(mContents)
+	{
+		char* buffer = (char*)mContents->lock(sw::PUBLIC);
+		mIsMapped = true;
+		mOffset = offset;
+		mLength = length;
+		mAccess = access;
+		return buffer + offset;
+	}
+	return nullptr;
+}
+
+bool Buffer::unmap()
+{
+	if(mContents)
+	{
+		mContents->unlock();
+	}
+	mIsMapped = false;
+	mOffset = 0;
+	mLength = 0;
+	mAccess = 0;
+	return true;
+}
+
 sw::Resource *Buffer::getResource()
 {
 	return mContents;