Add offset to memory allocations

src/gpu/vk/GrVkBuffer.h

Index: src/gpu/vk/GrVkBuffer.h
diff --git a/src/gpu/vk/GrVkBuffer.h b/src/gpu/vk/GrVkBuffer.h
index 141b2a378f3e6fed4a10ca652257ac0ccdcfc457..86c3248d03bda778725a707826604712e68b8558 100644
--- a/src/gpu/vk/GrVkBuffer.h
+++ b/src/gpu/vk/GrVkBuffer.h
@@ -26,6 +26,7 @@ public:
 
     VkBuffer       buffer() const { return fResource->fBuffer; }
     VkDeviceMemory alloc() const { return fResource->fAlloc; }
+    VkDeviceSize   offset() const { return fResource->fOffset; }
     const GrVkResource* resource() const { return fResource; }
     size_t         size() const { return fDesc.fSizeInBytes; }
 
@@ -53,10 +54,13 @@ protected:
 
     class Resource : public GrVkResource {
     public:
-        Resource(VkBuffer buf, VkDeviceMemory alloc) : INHERITED(), fBuffer(buf), fAlloc(alloc) {}
+        Resource(VkBuffer buf, VkDeviceMemory alloc, VkDeviceSize offset) 
+            : INHERITED(), fBuffer(buf), fAlloc(alloc), fOffset(offset) {}
 
-        VkBuffer fBuffer;
+        VkBuffer       fBuffer;
         VkDeviceMemory fAlloc;

[egdaniel, 2016/05/31 13:22:14]

I haven't though deeply into this, but do you think there would be any advantage
to having like a GrVkDeviceMemory class that would wrap the VkDeviceMemory and
offsets so the images/buffers don't need to know about them?

[jvanverth1, 2016/05/31 22:05:57]

I added a GrVkAlloc struct to GrVkTypes that wraps both the VkDeviceMemory and
the offset. I considered using a class, but it looked like the members would end
up being effectively public, so went for the simpler approach.

+        VkDeviceSize   fOffset;
+
     private:
         void freeGPUData(const GrVkGpu* gpu) const;