[kafasam]

What

On AMD, the game's TAAU neural upscaler is replaced by a bilinear stand-in (HMMA cost issue #52). This replaces that bilinear with FSR 1's EASU (12-tap edge-adaptive) + RCAS (contrast-capped sharpening) as two GLSL compute shaders.

Why

Bilinear at 50% internal scale loses all edge detail — foliage smears, distant geometry loses definition. EASU preserves edges and detail at the same resolution with ~0.5ms GPU cost (measured on RX 6700 XT). The EASU/RCAS shader code was already in the repo (inherited from TOTKPort in gpu/render/rx_present_fx.cpp) — this ports it to GLSL compute and wires it into the existing stand-in site.

Changes

• gpu/vk/shaders/taau_easu.comp (new) — FSR 1 EASU, 8×8 workgroups, reads RGB9E5, writes B10G11R11
• gpu/vk/shaders/taau_rcas.comp (new) — RCAS with the stand-in's flash/NaN history clamp preserved
• gpu/vk/vk_draw.cpp — typed_upscale builds three pipelines off one push-descriptor layout; EASU → barrier → RCAS
• SPIR-V headers compiled with glslang 16.6.0 (push-constant offsets verified in disassembly)
• Escape hatches: RX_VK_TAAU_MODE=bilinear (old path), RX_VK_TAAU_SHARPNESS=<stops> (default 0.2)

Testing

• Built clean (0 failures) on the proven recipe (llvm-mingw, 599 files)
• Smoke-tested on RX 6700 XT: alive 22+ min, save loaded, stable GPU stats, clean exit
• Played through Hyrule Field and graveyard scenes: visually sharper than bilinear (especially foliage edges, distant detail), no artifacts
• 25→28 fps in the graveyard (though this build also includes RX_VK_ASYNC=1 — the EASU itself costs ~0.5ms)
• Old stand-in untouched — revert with RX_VK_TAAU_MODE=bilinear

Note

This is quality-only — it won't raise fps in CPU-bound scenes (the frame is guest-emulation-bound). But it gives the 50% Resolution row a proper upscaler instead of a plain blit, at essentially zero GPU cost.

AI assistance disclosure: the EASU/RCAS port and pipeline wiring were developed with AI assistance, verified and tested by a human on the affected hardware.

[kafasam]

Tested on RX 6700 XT (RDNA2) at 4K/50% scale: 28-33 fps with the EASU+RCAS active (also running RX_VK_ASYNC=1 + RX_VK_BATCH=1 + RX_VK_PRESENT_QUEUE=1). The upscaler costs ~0.5ms GPU (measured 16.1ms/frame with EASU vs 15.5ms with bilinear). Visually: foliage edges and distant detail are noticeably sharper than bilinear. No artifacts observed. A/B revert via RX_VK_TAAU_MODE=bilinear works as expected.

[kafasam]

Thanks for the thorough re-review! All four fixes are verified — I've addressed the two merge blockers:

1. Unrelated commits removed: the branch now contains only the two EASU commits (the shader work + the review fixes). The readback flush (26b9466) and memory leak fix (8fb0290) are split into separate branches (readback-flush-only, memory-leak-only) and will be submitted as their own PRs.

2. Rebase: I'll rebase onto current main (which now includes feat(vk): FXAA in the gameplay TAAU stand-in (edges on cards without the network) #1115 and the v2.0.12 changes) once the branch split is confirmed clean. Will push the rebased version shortly.

The forced update is already on fsr1-easu-rcas — the branch is now exactly the EASU work and nothing else.

[kafasam]

Rebased onto v2.0.14 and split — this branch now contains only the two EASU commits on top of current main. The readback flush and memory leak fix are submitted as #1905 and #1906.

[kafasam]

Rebased onto current main (4d68bc8) per review, as commit c3728dc. The readme change applied clean; gpu/vk/vk_draw.cpp needed conflict resolution, as on the v2.1.0-rc.3 rebase:

• forward declarations: main's temporal_rejected_network kept, typed_upscale carries the new src_w/src_h params;
• the generic RGB9E5 call site: main's input_view && output_view null-checks kept, source size passed through;
• the dispatch: main's FXAA bit computation kept but gated to the bilinear branch only (if (bilinear && temporal && fxaa)) — the EASU push-constant's valid field expects 0/1 and EASU's edge-adaptive kernel replaces FXAA; the bilinear/pipe_linear vs EASU pipe_easu+pipe_rcas split with the mid image is unchanged;
• readme: both sides' paragraphs kept (RX_VK_WB_MAX_KB, RX_VK_TAAU_MODE/SHARPNESS).

Update: the two Python test suites pass against the rebased tree with the llvm-mingw toolchain — test_upscale_fallback.py (all 23 cases) and test_taau_env_lookup.py.

[Joey-Magnus]

The c3728dc rebase is good: gpu/vk/vk_draw.cpp and readme.md merge cleanly with current main. The only conflict left is tests/test_taau_env_lookup.py, where #2042 rewrote the file to include hookshot_env.h and wrap env_on. Keep main's version and add your src_w/src_h spy changes on top. At the PR head, test_taau_fxaa, test_taau_env_lookup and test_upscale_fallback pass locally.

The blocker is CI. The title "gpu/vk: FSR 1 ..." fails the Conventional Commit check, so only that check has run, and the Windows and llvm-mingw builds of the new shaders have never been run. Something like feat(vk): FSR 1 EASU + RCAS in place of the bilinear TAAU stand-in would pass.

One thing to note before merge: taau_key picks the stand-in wherever mma_software is set (vk_coopmat.cpp). That covers AMD, Intel, the GTX 16xx cards and the Steam Deck, so FSR 1 replaces FXAA by default on every one of them. You measured 0.5 ms on a 6700 XT. A timing on the Deck or on an Intel iGPU would show the default is safe at the low end.

[kafasam]

Rebased onto current main (ef81aee) as asked; the head is now 4876761, still the same two commits.

Conflict resolved: only tests/test_taau_env_lookup.py, as you said. I kept main's version from #2042 (the hookshot_env.h include through -include / /FI, and the env_on wrapper over the fixture's environment) and put this PR's spy changes on top: the src_w/src_h arguments of typed_upscale, the input texture resolved through ViewUse::Sample, and the "no resolved input texture" rejection. The branch's copy of that file had CRLF line endings where main's is LF, which is why the whole file showed as conflicting; it is LF now, and the diff against main for that file is +21/-9.

gpu/vk/vk_draw.cpp and readme.md applied without conflict. main's changes in the TAAU code since the last rebase were the getenv to env_on conversions (RX_VK_TAAU_CLAMP, RX_VK_TAAU_HIST_LEAK), and they are kept as main has them. No conflict markers anywhere in the diff.

Tests at 4876761, llvm-mingw clang++ (x86_64-w64-mingw32) on Windows:

• tests/test_upscale_fallback.py: pass
• tests/test_taau_env_lookup.py: pass (seven key configurations; rejected lookups removed, eligible per-call forwarding preserved)
• tests/test_taau_fxaa.py: pass

Title: changed to feat(vk): FSR 1 EASU + RCAS in place of the bilinear TAAU stand-in, your suggestion, so the Conventional Commit check passes and the builds can run. The Windows and llvm-mingw builds of the new shaders still have not run in CI.

Not done: the timing on a Steam Deck or an Intel iGPU. I only have the 6700 XT figure, so whether FSR 1 is a safe default at the low end (everywhere mma_software is set) is still open.

[Joey-Magnus]

Both points from my last review are done: the title passes, and 4876761 merges cleanly with current main. I merged it into main and ran tests/run_all.py: 426 passed, and the only failure is test_lift_cache, which fails on main here too. test_taau_env_lookup, test_taau_fxaa and test_upscale_fallback all pass. CI's builds still haven't run because the workflows are waiting for approval, so the llvm-mingw build of the two new shaders is still unchecked.

The point still open is the default. typed_upscale now runs EASU+RCAS on every mma_software card (AMD, Intel, the GTX 16xx cards and the Deck), and in the generic RGB9E5 fallback too. That replaces #1115's FXAA on the strength of one 6700 XT timing. A number from a Deck or an Intel iGPU would settle it. Otherwise, keep FSR 1 opt-in until someone has one.

Smaller things:

• If pipe_easu or pipe_rcas fails to build, typed_upscale returns false and the network runs. Falling back to pipe_linear would keep the old stand-in instead.
• No test compares taau_easu_comp_spv.h or taau_rcas_comp_spv.h with their sources, the way test_taau_fxaa does for taau_upscale.