Vk: Add ability to get descriptor from buffer and check an error

src/Magnum/Vk/Buffer.h

@@ -132,6 +132,15 @@ class MAGNUM_VK_EXPORT Buffer {
             };
         }
 
+        VkDescriptorBufferInfo getDescriptor() {
+            VkDescriptorBufferInfo descriptor;
+            descriptor.buffer = _buffer;
+            descriptor.offset = 0;
+            descriptor.range = _size;
+
+            return descriptor;
+        }
+
     private:
         Device& _device;
         VkBuffer _buffer;

src/Magnum/Vk/DescriptorSet.h

@@ -89,6 +89,7 @@ class MAGNUM_VK_EXPORT DescriptorSetLayout {
             };
 
             VkResult err = vkCreateDescriptorSetLayout(_device, &descLayout, nullptr, &_layout);
+            MAGNUM_VK_ASSERT_ERROR(err);
         }
 
         /** @brief Copying is not allowed */