Fix staging buffer required size calculation (fixes bevyengine#1056)

* when doing a full asset copy (resize), prepare_uniform_buffers() is
  now called on all assets rather than just changed ones. This makes
  sure the staging buffer is large enough.

* set_required_staging_buffer_size_to_max() now doesn't overwrite the
  value computed by prepare_uniform_buffers() if the resulting size
  would be smaller.

Co-authored-by: François <[email protected]>

crates/bevy_render/src/render_graph/nodes/render_resources_node.rs

@@ -216,7 +216,9 @@ where
  }
  }
 
- self.required_staging_buffer_size = new_size;
+ if new_size > self.required_staging_buffer_size {
+ self.required_staging_buffer_size = new_size;
+ }
  }
 
  /// Update the staging buffer to provide enough space to copy data to target buffers.
@@ -698,6 +700,12 @@ fn asset_render_resources_node_system<T: RenderResources + Asset>(
 
  let resized = uniform_buffer_arrays.resize_buffer_arrays(render_resource_context);
  if resized {
+ // full asset copy needed, make sure there is also space for unchanged assets
+ for (asset_handle, asset) in assets.iter() {
+ if !changed_assets.contains_key(&asset_handle) {
+ uniform_buffer_arrays.prepare_uniform_buffers(asset_handle, asset);
+ }
+ }
  uniform_buffer_arrays.set_required_staging_buffer_size_to_max()
  }
  uniform_buffer_arrays.resize_staging_buffer(render_resource_context);