diff --git a/dlls/d3d9/buffer.c b/dlls/d3d9/buffer.c
index 11fdab42cb7..84ee9a16cd6 100644
--- a/dlls/d3d9/buffer.c
+++ b/dlls/d3d9/buffer.c
@@ -26,7 +26,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(d3d9);
 
 static inline IDirect3DVertexBuffer9Impl *impl_from_IDirect3DVertexBuffer9(IDirect3DVertexBuffer9 *iface)
 {
-    return CONTAINING_RECORD(iface, IDirect3DVertexBuffer9Impl, lpVtbl);
+    return CONTAINING_RECORD(iface, IDirect3DVertexBuffer9Impl, IDirect3DVertexBuffer9_iface);
 }
 
 static HRESULT WINAPI d3d9_vertexbuffer_QueryInterface(IDirect3DVertexBuffer9 *iface, REFIID riid, void **object)
@@ -50,7 +50,7 @@ static HRESULT WINAPI d3d9_vertexbuffer_QueryInterface(IDirect3DVertexBuffer9 *i
 
 static ULONG WINAPI d3d9_vertexbuffer_AddRef(IDirect3DVertexBuffer9 *iface)
 {
-    IDirect3DVertexBuffer9Impl *buffer = (IDirect3DVertexBuffer9Impl *)iface;
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
     ULONG refcount = InterlockedIncrement(&buffer->ref);
 
     TRACE("%p increasing refcount to %u.\n", iface, refcount);
@@ -68,7 +68,7 @@ static ULONG WINAPI d3d9_vertexbuffer_AddRef(IDirect3DVertexBuffer9 *iface)
 
 static ULONG WINAPI d3d9_vertexbuffer_Release(IDirect3DVertexBuffer9 *iface)
 {
-    IDirect3DVertexBuffer9Impl *buffer = (IDirect3DVertexBuffer9Impl *)iface;
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
     ULONG refcount = InterlockedDecrement(&buffer->ref);
 
     TRACE("%p decreasing refcount to %u.\n", iface, refcount);
@@ -88,11 +88,14 @@ static ULONG WINAPI d3d9_vertexbuffer_Release(IDirect3DVertexBuffer9 *iface)
     return refcount;
 }
 
-static HRESULT WINAPI d3d9_vertexbuffer_GetDevice(IDirect3DVertexBuffer9 *iface, IDirect3DDevice9 **device)
+static HRESULT WINAPI d3d9_vertexbuffer_GetDevice(IDirect3DVertexBuffer9 *iface,
+        IDirect3DDevice9 **device)
 {
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
+
     TRACE("iface %p, device %p.\n", iface, device);
 
-    *device = (IDirect3DDevice9 *)((IDirect3DVertexBuffer9Impl *)iface)->parentDevice;
+    *device = (IDirect3DDevice9 *)buffer->parentDevice;
     IDirect3DDevice9_AddRef(*device);
 
     TRACE("Returning device %p.\n", *device);
@@ -154,12 +157,13 @@ static HRESULT WINAPI d3d9_vertexbuffer_FreePrivateData(IDirect3DVertexBuffer9 *
 
 static DWORD WINAPI d3d9_vertexbuffer_SetPriority(IDirect3DVertexBuffer9 *iface, DWORD priority)
 {
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
     DWORD previous;
 
     TRACE("iface %p, priority %u.\n", iface, priority);
 
     wined3d_mutex_lock();
-    previous = wined3d_buffer_set_priority(((IDirect3DVertexBuffer9Impl *)iface)->wineD3DVertexBuffer, priority);
+    previous = wined3d_buffer_set_priority(buffer->wineD3DVertexBuffer, priority);
     wined3d_mutex_unlock();
 
     return previous;
@@ -167,12 +171,13 @@ static DWORD WINAPI d3d9_vertexbuffer_SetPriority(IDirect3DVertexBuffer9 *iface,
 
 static DWORD WINAPI d3d9_vertexbuffer_GetPriority(IDirect3DVertexBuffer9 *iface)
 {
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
     DWORD priority;
 
     TRACE("iface %p.\n", iface);
 
     wined3d_mutex_lock();
-    priority = wined3d_buffer_get_priority(((IDirect3DVertexBuffer9Impl *)iface)->wineD3DVertexBuffer);
+    priority = wined3d_buffer_get_priority(buffer->wineD3DVertexBuffer);
     wined3d_mutex_unlock();
 
     return priority;
@@ -180,10 +185,12 @@ static DWORD WINAPI d3d9_vertexbuffer_GetPriority(IDirect3DVertexBuffer9 *iface)
 
 static void WINAPI d3d9_vertexbuffer_PreLoad(IDirect3DVertexBuffer9 *iface)
 {
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
+
     TRACE("iface %p.\n", iface);
 
     wined3d_mutex_lock();
-    wined3d_buffer_preload(((IDirect3DVertexBuffer9Impl *)iface)->wineD3DVertexBuffer);
+    wined3d_buffer_preload(buffer->wineD3DVertexBuffer);
     wined3d_mutex_unlock();
 }
 
@@ -194,17 +201,17 @@ static D3DRESOURCETYPE WINAPI d3d9_vertexbuffer_GetType(IDirect3DVertexBuffer9 *
     return D3DRTYPE_VERTEXBUFFER;
 }
 
-static HRESULT WINAPI d3d9_vertexbuffer_Lock(IDirect3DVertexBuffer9 *iface,
-        UINT offset, UINT size, void **data, DWORD flags)
+static HRESULT WINAPI d3d9_vertexbuffer_Lock(IDirect3DVertexBuffer9 *iface, UINT offset, UINT size,
+        void **data, DWORD flags)
 {
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
     HRESULT hr;
 
     TRACE("iface %p, offset %u, size %u, data %p, flags %#x.\n",
             iface, offset, size, data, flags);
 
     wined3d_mutex_lock();
-    hr = wined3d_buffer_map(((IDirect3DVertexBuffer9Impl *)iface)->wineD3DVertexBuffer,
-            offset, size, (BYTE **)data, flags);
+    hr = wined3d_buffer_map(buffer->wineD3DVertexBuffer, offset, size, (BYTE **)data, flags);
     wined3d_mutex_unlock();
 
     return hr;
@@ -212,18 +219,21 @@ static HRESULT WINAPI d3d9_vertexbuffer_Lock(IDirect3DVertexBuffer9 *iface,
 
 static HRESULT WINAPI d3d9_vertexbuffer_Unlock(IDirect3DVertexBuffer9 *iface)
 {
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
+
     TRACE("iface %p.\n", iface);
 
     wined3d_mutex_lock();
-    wined3d_buffer_unmap(((IDirect3DVertexBuffer9Impl *)iface)->wineD3DVertexBuffer);
+    wined3d_buffer_unmap(buffer->wineD3DVertexBuffer);
     wined3d_mutex_unlock();
 
     return D3D_OK;
 }
 
-static HRESULT WINAPI d3d9_vertexbuffer_GetDesc(IDirect3DVertexBuffer9 *iface, D3DVERTEXBUFFER_DESC *desc)
+static HRESULT WINAPI d3d9_vertexbuffer_GetDesc(IDirect3DVertexBuffer9 *iface,
+        D3DVERTEXBUFFER_DESC *desc)
 {
-    IDirect3DVertexBuffer9Impl *buffer = (IDirect3DVertexBuffer9Impl *)iface;
+    IDirect3DVertexBuffer9Impl *buffer = impl_from_IDirect3DVertexBuffer9(iface);
     struct wined3d_resource_desc wined3d_desc;
     struct wined3d_resource *wined3d_resource;
 
@@ -280,7 +290,7 @@ HRESULT vertexbuffer_init(IDirect3DVertexBuffer9Impl *buffer, IDirect3DDevice9Im
 {
     HRESULT hr;
 
-    buffer->lpVtbl = &d3d9_vertexbuffer_vtbl;
+    buffer->IDirect3DVertexBuffer9_iface.lpVtbl = &d3d9_vertexbuffer_vtbl;
     buffer->ref = 1;
     buffer->fvf = fvf;
 
diff --git a/dlls/d3d9/d3d9_private.h b/dlls/d3d9/d3d9_private.h
index 9cb33c88520..fb6e7e651cf 100644
--- a/dlls/d3d9/d3d9_private.h
+++ b/dlls/d3d9/d3d9_private.h
@@ -251,10 +251,8 @@ HRESULT surface_init(IDirect3DSurface9Impl *surface, IDirect3DDevice9Impl *devic
  */
 typedef struct IDirect3DVertexBuffer9Impl
 {
-    /* IUnknown fields */
-    const IDirect3DVertexBuffer9Vtbl *lpVtbl;
-    LONG                    ref;
-
+    IDirect3DVertexBuffer9 IDirect3DVertexBuffer9_iface;
+    LONG ref;
     struct wined3d_buffer *wineD3DVertexBuffer;
     IDirect3DDevice9Ex *parentDevice;
     DWORD fvf;
diff --git a/dlls/d3d9/device.c b/dlls/d3d9/device.c
index 924d43e0750..0f33a271f40 100644
--- a/dlls/d3d9/device.c
+++ b/dlls/d3d9/device.c
@@ -853,7 +853,7 @@ static HRESULT WINAPI IDirect3DDevice9Impl_CreateVertexBuffer(IDirect3DDevice9Ex
     }
 
     TRACE("Created vertex buffer %p.\n", object);
-    *buffer = (IDirect3DVertexBuffer9 *)object;
+    *buffer = &object->IDirect3DVertexBuffer9_iface;
 
     return D3D_OK;
 }