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Solari: Reduce temporal shadow lag #25046

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JMS55 wants to merge 4 commits into
bevyengine:mainfrom
JMS55:solari7-previous-tlas
Open

Solari: Reduce temporal shadow lag #25046
JMS55 wants to merge 4 commits into
bevyengine:mainfrom
JMS55:solari7-previous-tlas

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@JMS55

@JMS55 JMS55 commented Jul 17, 2026

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Reduce DI shadow lag (doesn't seem to do much for GI, but hard to tell) by using the previous-frame TLAS for visibility testing in MIS when merging the temporal reservoir in.

This does cost more VRAM.

Thanks to @stuartparmenter for the idea.

@JMS55 JMS55 added A-Rendering Drawing game state to the screen S-Needs-Review Needs reviewer attention (from anyone!) to move forward C-Refinement Improves output quality, without fixing a clear bug or adding new functionality. labels Jul 17, 2026
@github-project-automation github-project-automation Bot moved this to Needs SME Triage in Rendering Jul 17, 2026
stuartparmenter added a commit to stuartparmenter/bevy that referenced this pull request Jul 18, 2026
Per-frame GPU-written vertex/index buffers become TLAS instances via
entity-keyed BLASes. Geometry BLAS builds fold into the TLAS build
encoder.

Geometry BLASes double-buffer (GeometryBlasEntry::previous_blas) so the
previous-frame TLAS retained for temporal MIS visibility (bevyengine#25046) keeps
referencing an intact BLAS instead of one rebuilt in place this frame.
@JMS55
JMS55 requested a review from SparkyPotato July 20, 2026 15:19

@SparkyPotato SparkyPotato left a comment

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The seconds TLAS scares me a bit but looks good otherwise lol

@JMS55 JMS55 added S-Ready-For-Final-Review This PR has been approved by the community. It's ready for a maintainer to consider merging it and removed S-Needs-Review Needs reviewer attention (from anyone!) to move forward labels Jul 20, 2026
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A-Rendering Drawing game state to the screen C-Refinement Improves output quality, without fixing a clear bug or adding new functionality. S-Ready-For-Final-Review This PR has been approved by the community. It's ready for a maintainer to consider merging it

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3 participants