add sampler writes

vulkan.d

@@ -1987,6 +1987,13 @@ PrepareWrite(Vulkan* vk, VkWriteDescriptorSet* write, DescSet set, Descriptor* d
       {
         write.pTexelBufferView = &desc.buf_view.view;
       } break;
+    case Sampler:
+      {
+        VkDescriptorImageInfo* info = Alloc!(VkDescriptorImageInfo)(arena);
+
+        info.sampler     = desc.sampler;
+        write.pImageInfo = info;
+      } break;
     default: assert(false, "Unsupported descriptor type");
   }
 }