[thuanquang]

What

A sampler with FORCE_DEGAMMA (S# word 0 bit 20) makes main refuse every texture that is not sRGB and has no sRGB view, for example a 32-bit float texture:

a texture of guest format 22, which is not sRGB and has no sRGB view, is sampled through a sampler that forces sRGB decoding, which is not implemented

On an RX 6700 XT the bit changes only 8-bit-per-channel formats. I measured it through the hardware oracle's HIP path (scripts and tables): a 64x1 linear texture, each lane reads its own texel at its centre (point) and halfway to the next one (bilinear), with two random fills, so 512 component values per format and mode:

• UNORM 8, 8_8 and 8_8_8_8 with the bit read bit for bit as 8_SRGB, 8_8_SRGB and 8_8_8_8_SRGB, as main already samples them (through an sRGB view);
• SNORM 8, 8_8 and 8_8_8_8 with the bit read bit for bit as those sRGB formats over the same bytes;
• every other format I measured samples bit for bit the same with and without the bit, point and bilinear: 16, 16_16 and 16_16_16_16 UNORM, SNORM and FLOAT (guest formats 7, 8, 13, 23, 24, 29, 65, 66, 71), 32, 32_32 and 32_32_32_32 FLOAT (22, 64, 77), 10_11_11 FLOAT (36), 2_10_10_10 UNORM (50), 5_9_9_9 FLOAT (132), 5_6_5, 1_5_5_5 and 4_4_4_4 UNORM (133, 134, 136), and BC4, BC5 and BC6H, unsigned and signed (175 to 180). The sRGB formats 128 to 130 do too.

ForcesDegammaOn now leaves the formats of the last item to their plain view, as if the bit were clear. SNORM 8, 8_8 and 8_8_8_8 (they would need an sRGB view of an SNORM image) and formats I did not measure still throw. The FORCE_DEGAMMA debt entry is cut to what is still open.

Tested

Windows 11 26200, AMD Radeon RX 6700 XT (gfx1031), driver 32.0.21045.5002, WinLibs GCC 15.2.0 r7, Release, BUILD_TESTING=ON, on main 585075cb7. The runs use VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation (Vulkan-ValidationLayers vulkan-sdk-1.4.363.0, built locally), ANYPS5_NO_SHADER_CACHE=1, ANYPS5_REQUIRE_VULKAN=1 and ctest -V, with the implicit overlay layers on this PC switched off (VK_LOADER_LAYERS_DISABLE=~implicit~); no log reports the layer as not found.

• agc_driver_image_sample_force_degamma no longer expects guest format 22 (32_FLOAT) to be refused. It now requires a point sample of 32_FLOAT and of BC4 UNORM through a FORCE_DEGAMMA sampler to equal, bit for bit, the sample without it, and it expects 8_8_8_8_SNORM (guest format 57) to be refused instead.
• agc_driver_graphics checks the list: IgnoresForcedDegamma holds for 7, 13, 22, 36, 50, 77, 132, 133, 175 and 179, and not for 1, 2, 14, 15, 56, 57, 128, 130, 169, 171, 173 and 181 (8-bit UNORM, SNORM and sRGB formats, and BC1, BC2, BC3 and BC7 UNORM).
• With this change both pass 3 of 3, with no VUID- errors.
• With only the Sampler.cpp line reverted, agc_driver_image_sample_force_degamma fails: a texture of guest format 22, which is not sRGB and has no sRGB view, is sampled through a sampler that forces sRGB decoding, which is not implemented. No VUID- errors.
• main 8c9161eac with its own version of both tests: they pass, with no VUID- errors.
• python tools/check_conventions.py --base origin/main with this title and body passes. python tools/pr_overlap.py --branch fix/force-degamma-unchanged-formats lists feat(agc): read sampler border colours from the border colour table #6804, which adds a debt entry on the line above the FORCE_DEGAMMA entry, and fix(agc): give a block-copied BC texture an sRGB view for FORCE_DEGAMMA samplers #7799 (its pushed head no longer touches the debt file); the rest are pull requests that conflict with main and share only the debt file, plus fix(shader): emulate sRGB sampling when unsupported #5371, which edits the same test file for its R8 and RG8 sRGB fallback.
• @wachi35676 ran this head merged into main 9127ea36d on an NVIDIA RTX 5070 Ti (driver 617.42) and an AMD Radeon iGPU (RDNA2, 1002:13c0, AMD proprietary driver 2026.04.17), Windows 11 Home 26300, ANYPS5_REQUIRE_VULKAN=1: agc_driver_image_sample_force_degamma, agc_driver_graphics and the other related tests, 16 in all, pass on both, and with Sampler.cpp back to main agc_driver_image_sample_force_degamma fails on both with the message above. On WSL Ubuntu 24.04 with llvmpipe (Mesa 25.2.8), with this and six other PRs merged, 61 of the 62 related tests pass; the other fails on a WSL write-watch limit.
• Not run: the full suite on this head; titles (no report of this refusal names one of these formats); the console's gfx1013. The hardware result for these formats is the RX 6700 XT measurement above only.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Fixes: none
• Unblocks: none
• GPUs tested: AMD Radeon RX 6700 XT (gfx1031), driver 32.0.21045.5002, Windows 11 26200; by @wachi35676: NVIDIA RTX 5070 Ti, driver 617.42, and AMD Radeon iGPU (RDNA2, 1002:13c0), AMD proprietary driver 2026.04.17, Windows 11 Home 26300; llvmpipe (Mesa 25.2.8), WSL Ubuntu 24.04
• AI-assisted: yes (Claude Code)

🤖 Generated with Claude Code

[github-actions]

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 2434	docs/dev/debt/libSceAgcDriver.md
PR 4448	docs/dev/debt/libSceAgcDriver.md
PR 4449	docs/dev/debt/libSceAgcDriver.md
PR 5058	docs/dev/debt/libSceAgcDriver.md
PR 5371	core/libs/prx/libSceAgcDriver/tests/execution/ImageSampleForceDegamma.cpp
PR 5372	docs/dev/debt/libSceAgcDriver.md
PR 5499	docs/dev/debt/libSceAgcDriver.md
PR 5925	docs/dev/debt/libSceAgcDriver.md
PR 6146	docs/dev/debt/libSceAgcDriver.md
PR 6194	docs/dev/debt/libSceAgcDriver.md
PR 6223	docs/dev/debt/libSceAgcDriver.md
PR 6273	docs/dev/debt/libSceAgcDriver.md
PR 6280	docs/dev/debt/libSceAgcDriver.md
PR 6300	docs/dev/debt/libSceAgcDriver.md
PR 6412	docs/dev/debt/libSceAgcDriver.md
PR 6481	docs/dev/debt/libSceAgcDriver.md
PR 6548	docs/dev/debt/libSceAgcDriver.md
PR 6636	docs/dev/debt/libSceAgcDriver.md
PR 6683	docs/dev/debt/libSceAgcDriver.md
PR 6804	core/libs/prx/libSceAgcDriver/Graphics/src/Sampler.cpp docs/dev/debt/libSceAgcDriver.md
PR 6808	docs/dev/debt/libSceAgcDriver.md
PR 6867	docs/dev/debt/libSceAgcDriver.md
PR 6868	docs/dev/debt/libSceAgcDriver.md
PR 6926	docs/dev/debt/libSceAgcDriver.md
PR 6946	docs/dev/debt/libSceAgcDriver.md
PR 6947	core/libs/prx/libSceAgcDriver/Graphics/src/Sampler.cpp docs/dev/debt/libSceAgcDriver.md
PR 6977	core/libs/prx/libSceAgcDriver/tests/TextureFormat.cpp docs/dev/debt/libSceAgcDriver.md
PR 7256	docs/dev/debt/libSceAgcDriver.md
PR 7446	docs/dev/debt/libSceAgcDriver.md
PR 7449	docs/dev/debt/libSceAgcDriver.md
PR 7505	docs/dev/debt/libSceAgcDriver.md
PR 7604	docs/dev/debt/libSceAgcDriver.md
PR 7642	core/libs/prx/libSceAgcDriver/Graphics/src/Sampler.cpp docs/dev/debt/libSceAgcDriver.md
PR 7800	docs/dev/debt/libSceAgcDriver.md
PR 8564	docs/dev/debt/libSceAgcDriver.md
PR 8592	docs/dev/debt/libSceAgcDriver.md

[wachi35676]

NVIDIA and AMD iGPU runs of eeb1c4f03. The PR's runs were on an RX 6700 XT only.

Windows 11 Home 26300, WinLibs GCC 15.2.0, Release, BUILD_TESTING=ON, main 9127ea36d with this head merged. GPUs: RTX 5070 Ti (NVIDIA 617.42) and the AMD Radeon iGPU (RDNA2, 1002:13c0, AMD proprietary driver 2026.04.17, ANYPS5_GPU=AMD). ANYPS5_REQUIRE_VULKAN=1, ctest -j4, failures rerun serially (there were none).

• agc_driver_image_sample_force_degamma, agc_driver_graphics, every agc_driver_image_sample_* test, texture_format_lookup, agc_driver_srgb8_color_target and the emulated color compare tests (16 in all) pass on both GPUs.
• Negative control: with Sampler.cpp back to main, agc_driver_image_sample_force_degamma fails on both GPUs with a texture of guest format 22, which is not sRGB and has no sRGB view, is sampled through a sampler that forces sRGB decoding, which is not implemented.
• The guest format numbers in IgnoresForcedDegamma match the formats named in the description in kFormatLookup (for example 22 R32_SFLOAT, 36 B10G11R11_UFLOAT, 132 E5B9G9R9, 175-180 BC4/BC5/BC6H). FORCE_DEGAMMA is bit 20 of S# word 0 in Mesa gfx10-rsrc.json.
• On the host, the new RequireSame rows for 32_FLOAT and BC4 compare two samples through the same Vulkan view. They show that the refusal is gone. Whether the result matches hardware depends on the gist's RX 6700 XT measurements, which I could not repeat: the oracle needs Linux /dev/kfd.
• Linux: WSL Ubuntu 24.04, GCC 13.3, llvmpipe (Mesa 25.2.8), main 9127ea36d with fix(agc): accept a draw without a pixel program while CB_COLOR_CONTROL disables color #8078, fix(agc): accept PA_CL_CLIP_CNTL CLIP_DISABLE without depth clamp #8046, fix(agc): sample formats that FORCE_DEGAMMA leaves unchanged without it #8069, fix(shader): link a table call whose V# is a slice of an s_load_dwordx8 or s_load_dwordx16 #8070, fix(agc): offset the CMASK of a plain color target slice by its slice #7668, feat(shader): decode MIMG opcode 0xb8 as image_sample_c_o_a #8015 and perf(agc): reuse sampled snapshot byte buffers across cache entry replacement #8026 merged together: 61 of the 62 related tests pass; the other, agc_driver_depth_compare_copy, fails with the guest block is not write-watched after WSL reports asynchronous userfaultfd write protection failed, an environment limit.

AI-assisted: yes (Claude Code); results above were run on this machine.