RT VRAM: lower opacity-micromap resolution for distant objects #580

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opened 2026-10-09 01:49:13 +00:00 by sky_line · 0 comments

sky_line commented

2026-10-09 01:49:13 +00:00

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Measured in a heavy region (2026-10-09): RT acceleration structures (rt-as) are about 1.7 GB, as much as all the geometry, and the opacity micromaps (rt-mask) are 354 MB. Follow-up to #573.

Idea

OMM masks (alpha cut-outs such as leaves and fences) use a lower subdivision level for distant or small instances, or only the coarse level beyond a threshold.

Trade-offs

Alpha-tested edges in RT shadows and reflections get slightly coarser at range.

Done when

rt-mask drops with no visible change near the camera.

Measured in a heavy region (2026-10-09): RT acceleration structures (`rt-as`) are about 1.7 GB, as much as all the geometry, and the opacity micromaps (`rt-mask`) are 354 MB. Follow-up to #573. ## Idea OMM masks (alpha cut-outs such as leaves and fences) use a lower subdivision level for distant or small instances, or only the coarse level beyond a threshold. ## Trade-offs - Alpha-tested edges in RT shadows and reflections get slightly coarser at range. ## Done when `rt-mask` drops with no visible change near the camera.

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2026-10-09 01:49:13 +00:00

sky_line added this to the Slipstream project

2026-10-09 01:49:13 +00:00

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2026-10-09 04:40:40 +00:00

RT: opacity micromaps (VK_EXT_opacity_micromap) for hardware alpha-tested shadows, shader alpha-test fallback #194

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