# Objective
- Adding a node to the render_graph can be quite verbose and error prone
because there's a lot of moving parts to it.
## Solution
- Encapsulate this in a simple utility method
- Mostly intended for optional nodes that have specific ordering
- Requires that the `Node` impl `FromWorld`, but every internal node is
built using a new function taking a `&mut World` so it was essentially
already `FromWorld`
- Use it for the bloom, fxaa and taa, nodes.
- The main nodes don't use it because they rely more on the order of
many nodes being added
---
## Changelog
- Impl `FromWorld` for `BloomNode`, `FxaaNode` and `TaaNode`
- Added `RenderGraph::add_node_edges()`
- Added `RenderGraph::sub_graph()`
- Added `RenderGraph::sub_graph_mut()`
- Added `RenderGraphApp`, `RenderGraphApp::add_render_graph_node`,
`RenderGraphApp::add_render_graph_edges`,
`RenderGraphApp::add_render_graph_edge`
## Notes
~~This was taken out of https://github.com/bevyengine/bevy/pull/7995
because it works on it's own. Once the linked PR is done, the new
`add_node()` will be simplified a bit since the input/output params
won't be necessary.~~
This feature will be useful in most of the upcoming render nodes so it's
impact will be more relevant at that point.
Partially fixes#7985
## Future work
* Add a way to automatically label nodes or at least make it part of the
trait. This would remove one more field from the functions added in this
PR
* Use it in the main pass 2d/3d
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Co-authored-by: Carter Anderson <mcanders1@gmail.com>
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