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Fix hooked video darkening for *_SRGB-backbuffer games

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The host sampled the shared backbuffer copy through a view typed exactly like the
game's backbuffer. For games whose backbuffer is an *_SRGB format (e.g. Life is
Strange: Before the Storm -- confirmed R8G8B8A8_UNORM_SRGB / fmt 29 via the hook
log), the GPU decoded sRGB->linear on the sample, and the host then wrote those
linear values straight to its plain-UNORM swapchain with no re-encode, so the
mirror came out noticeably darker than the game.

Sample the copy as the plain-UNORM sibling of the format (srgb_to_unorm) so the
bytes pass through unchanged -- matching what WGC already does. The UNORM and
*_SRGB formats share a typeless group, so CopyResource from the producer's sRGB
texture into the host's UNORM copy is allowed. Non-sRGB formats are unaffected.

Adds srgb_format_test locking the mapping. All 6 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
BlackMark
2026-06-20 14:22:31 +02:00
parent edf2da69d8
commit 24d66020f6
5 changed files with 99 additions and 2 deletions
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6
tests/CMakeLists.txt
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@@ -59,6 +59,12 @@ target_link_libraries(audio_hook_test PRIVATE
add_test(NAME audio_hook_test COMMAND audio_hook_test)
# Unit test for the sRGB->UNORM format mapping the hooked video path uses to avoid
# darkening *_SRGB-backbuffer games. Header-only, no device.
add_executable(srgb_format_test srgb_format_test.cpp)
target_include_directories(srgb_format_test PRIVATE ${CMAKE_SOURCE_DIR}/host/src)
add_test(NAME srgb_format_test COMMAND srgb_format_test)
# In-process self-test for the Present-hook video path. Reuses the shipping
# present_hook.cpp and drives a real D3D11 swapchain in the same process, so it
# exercises the IDXGISwapChain::Present inline hook, the shared keyed-mutex

41
tests/srgb_format_test.cpp Normal file
View File

@@ -0,0 +1,41 @@
// Unit test for srgb_to_unorm (host/src/capture/dxgi_format.hpp): the hooked
// video path samples the shared backbuffer copy as plain UNORM so an *_SRGB game
// backbuffer isn't darkened by an sRGB->linear decode the host never re-encodes.
// Locks the format mapping that fix depends on. No device needed.
#include <cstdio>
#include "capture/dxgi_format.hpp"
using namespace coop;
namespace
{
int g_failures = 0;
void expect(DXGI_FORMAT in, DXGI_FORMAT want, const char* what)
{
const DXGI_FORMAT got = srgb_to_unorm(in);
if (got != want)
{
std::printf(" FAIL: %s (got %d, want %d)\n", what, static_cast<int>(got), static_cast<int>(want));
++g_failures;
}
}
} // namespace
int main()
{
// sRGB formats map to their plain-UNORM sibling.
expect(DXGI_FORMAT_R8G8B8A8_UNORM_SRGB, DXGI_FORMAT_R8G8B8A8_UNORM, "R8G8B8A8 sRGB -> UNORM");
expect(DXGI_FORMAT_B8G8R8A8_UNORM_SRGB, DXGI_FORMAT_B8G8R8A8_UNORM, "B8G8R8A8 sRGB -> UNORM");
expect(DXGI_FORMAT_B8G8R8X8_UNORM_SRGB, DXGI_FORMAT_B8G8R8X8_UNORM, "B8G8R8X8 sRGB -> UNORM");
// Non-sRGB formats pass through unchanged.
expect(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_FORMAT_R8G8B8A8_UNORM, "R8G8B8A8 UNORM passthrough");
expect(DXGI_FORMAT_B8G8R8A8_UNORM, DXGI_FORMAT_B8G8R8A8_UNORM, "B8G8R8A8 UNORM passthrough");
expect(DXGI_FORMAT_R10G10B10A2_UNORM, DXGI_FORMAT_R10G10B10A2_UNORM, "R10G10B10A2 passthrough");
expect(DXGI_FORMAT_R16G16B16A16_FLOAT, DXGI_FORMAT_R16G16B16A16_FLOAT, "RGBA16F passthrough");
std::printf(g_failures == 0 ? "SRGB FORMAT TEST PASS\n" : "SRGB FORMAT TEST FAILED (%d)\n", g_failures);
return g_failures == 0 ? 0 : 1;
}