Fixed sample app crashing when window is minimized

src/VulkanSample.cpp

diff --git a/src/VulkanSample.cpp b/src/VulkanSample.cpp
index d1ed500..3edd48e 100644
--- a/src/VulkanSample.cpp
+++ b/src/VulkanSample.cpp
@@ -2420,8 +2420,22 @@
 #endif
 }
 
+static bool IsWindowMinimizedOrZeroSized()
+{
+    if((g_hWnd == NULL) || IsIconic(g_hWnd))
+        return true;
+
+    RECT clientRect = {};
+    GetClientRect(g_hWnd, &clientRect);
+    return clientRect.right <= clientRect.left
+        || clientRect.bottom <= clientRect.top;
+}
+
 static void RecreateSwapChain()
 {
+    if(IsWindowMinimizedOrZeroSized())
+        return;
+
     vkDeviceWaitIdle(g_hDevice);
     DestroySwapchain(false);
     CreateSwapchain();
@@ -2738,10 +2752,10 @@
             TranslateMessage(&msg);
             DispatchMessage(&msg);
         }
+        else if(IsWindowMinimizedOrZeroSized())
+            Sleep(25);
         else
-		{
             DrawFrame();
-		}
     }
 
     return (int)msg.wParam;;