Merge pull request #39 from mvd4/bugfix/add_missing_buffer_usage_flag

vku::VertexBuffer: add vk::BufferUsageFlagBits::eTransferDst to fix validation error

Author: lhog

include/vku/vku.hpp

@@ -1271,7 +1271,7 @@ class VertexBuffer : public GenericBuffer {
   VertexBuffer() {
   }
 
-  VertexBuffer(const vk::Device &device, const vk::PhysicalDeviceMemoryProperties &memprops, size_t size) : GenericBuffer(device, memprops, vk::BufferUsageFlagBits::eVertexBuffer, size, vk::MemoryPropertyFlagBits::eDeviceLocal) {
+  VertexBuffer(const vk::Device &device, const vk::PhysicalDeviceMemoryProperties &memprops, size_t size) : GenericBuffer(device, memprops, vk::BufferUsageFlagBits::eVertexBuffer | vk::BufferUsageFlagBits::eTransferDst, size, vk::MemoryPropertyFlagBits::eDeviceLocal) {
   }
 };