diff --git a/example/Vulkan/VKBuffer.cpp b/example/Vulkan/VKBuffer.cpp
index 36fce2b9..cfaf5210 100644
--- a/example/Vulkan/VKBuffer.cpp
+++ b/example/Vulkan/VKBuffer.cpp
@@ -7,11 +7,18 @@ Buffer::~Buffer()
     vkFreeMemory(device,mem,nullptr);
 }
 
-uint8_t *Buffer::Map()
+uint8_t *Buffer::Map(uint32_t start,uint32_t size)
 {
     uint8_t *p;
 
-    if(vkMapMemory(device,mem,0,buffer_info.range,0,(void **)&p)==VK_SUCCESS)
+    if(start>buffer_info.range
+     ||start+size>buffer_info.range)
+        return(nullptr);
+
+    if(start==0&&size==0)
+        size=buffer_info.range;
+
+    if(vkMapMemory(device,mem,start,size,0,(void **)&p)==VK_SUCCESS)
         return p;
 
     return nullptr;
diff --git a/example/Vulkan/VKBuffer.h b/example/Vulkan/VKBuffer.h
index b153ac79..26e10f00 100644
--- a/example/Vulkan/VKBuffer.h
+++ b/example/Vulkan/VKBuffer.h
@@ -26,7 +26,7 @@ public:
 
     virtual ~Buffer();
 
-    uint8_t *Map();
+    uint8_t *Map(uint32_t start=0,uint32_t size=0);
     void Unmap();
 };//class Buffer
 VK_NAMESPACE_END