Enable dirty region management within the Embedder API #35022
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…tiple damage rectangles.
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| typedef void (*FlutterFrameBufferWithDamageCallback)( | ||
| void* /* user data */, | ||
| const intptr_t /* fbo id */, | ||
| FlutterDamage* /* existing damage */); |
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@chinmaygarde this is an out parameter, the embedder populates this struct, but it has a list of rects in it. Do you have any recommendations of how the embedder can supply a buffer for the engine to fill out?
shell/platform/embedder/embedder.h
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| /// responsible for providing populate_existing_damage_callback with the FBO's | ||
| /// ID. Not specifying populate_existing_damage_callback will result in full | ||
| /// repaint (i.e. rendering all the pixels on the screen at every frame). | ||
| FlutterFrameBufferWithDamageCallback populate_existing_damage_callback; |
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remove: _callback at the end.
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Sounds good! I updated the name to populate_existing_damage.
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minor rename suggestion, but LGTM otherwise
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The changes proposed in this PR enable dirty region management within the Embedder API for OpenGL rendering backends. That is, embedders will only render the regions that changed in between frames rather than rendering the entire screen every time. These changes provide a framework for reducing raster time and energy consumption across all embedders using the Flutter Embedder API, immediately affecting OpenGL-based embedders such as the ones implemented for Linux and Windows platforms. In the future, after support for Metal is added, MacOS platforms should also be benefitted.
The implementation adds a new struct, FlutterDamage, to the Embedder API and updates the present and FBO callbacks to handle the necessary information for dirty region management. More specifically to OpenGL, the Embedder GL Surface and the GL Skia GPU have been updated to take damaged regions into account.
The relevant tests have been included inside the embedder_unittests_gl files.
I also ran a local benchmark using this implementation of the embedder with partial repaint within an example of a screen with a loading spinner in the center. The version not using partial repaint had an average present time of 4,171μs/frame while the version using partial repaint had an average present time of 2,457μs/frame.
Pre-launch Checklist
writing and running engine tests.
///).