From b08eefd4e22d2d770fd0a72aef1424a9e112bc46 Mon Sep 17 00:00:00 2001
From: UjinT34 <ujint34@mail.ru>
Date: Tue, 28 Apr 2026 21:57:46 +0300
Subject: [PATCH] fix unmodified copy

---
 src/config/values/ConfigValues.cpp |  2 ++
 src/helpers/Monitor.cpp            | 13 ++++++++-----
 src/helpers/Monitor.hpp            |  2 +-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/config/values/ConfigValues.cpp b/src/config/values/ConfigValues.cpp
index ac213a421..260425cf1 100644
--- a/src/config/values/ConfigValues.cpp
+++ b/src/config/values/ConfigValues.cpp
@@ -539,6 +539,8 @@ std::vector<SP<IValue>> Values::getConfigValues() {
                 {.min = 0, .max = 2, .map = OptionMap{{"disable", 0}, {"enable", 1}, {"auto", 2}}}),
         MS<Int>("render:non_shader_cm_interop", "non_shader_cm interaction with ctm proto (hyprsunset and similar).", 2,
                 {.min = 0, .max = 2, .map = OptionMap{{"disable", 0}, {"enable", 1}, {"auto", 2}}}),
+        MS<Int>("render:fp16_sdr_tf", "Internal workbuffer transfer function for fp16 in SDR mode", 0,
+                {.min = 0, .max = 2, .map = OptionMap{{"default", 0}, {"linear", 1}, {"monitor", 2}}}),
 
         /*
          * cursor:
diff --git a/src/helpers/Monitor.cpp b/src/helpers/Monitor.cpp
index af79a4e3b..4f4e9a7b4 100644
--- a/src/helpers/Monitor.cpp
+++ b/src/helpers/Monitor.cpp
@@ -2550,6 +2550,8 @@ bool CMonitor::useFP16() {
 }
 
 PImageDescription CMonitor::workBufferImageDescription() {
+    static const auto PFP16TF = CConfigValue<Hyprlang::INT>("render:fp16_sdr_tf");
+
     if (!useFP16())
         return m_imageDescription;
 
@@ -2561,19 +2563,20 @@ PImageDescription CMonitor::workBufferImageDescription() {
     const auto& cached = m_cachedInternalDescription->value();
 
     // HDR
-    if (isHDRLikeTF || value.windowsScRGB) {
-        if (cached.primariesNamed != NColorManagement::CM_PRIMARIES_SRGB || cached.luminances != value.luminances)
+    if (isHDRLikeTF || value.windowsScRGB || *PFP16TF != 2) {
+        if (cached.transferFunction != LINEAR_IMAGE_DESCRIPTION->value().transferFunction || cached.luminances != value.luminances)
             m_cachedInternalDescription = LINEAR_IMAGE_DESCRIPTION->with(value.luminances);
         return m_cachedInternalDescription;
     }
 
     // SDR
-    if (cached.primariesNamed != NColorManagement::CM_PRIMARIES_BT2020 || cached.transferFunction != chooseTF(m_sdrEotf))
+    if (cached.transferFunction != chooseTF(m_sdrEotf))
         m_cachedInternalDescription = CImageDescription::from(SImageDescription{
             .transferFunction = chooseTF(m_sdrEotf),
             .primariesNameSet = true,
-            .primariesNamed   = NColorManagement::CM_PRIMARIES_BT2020,
-            .primaries        = NColorPrimaries::BT2020,
+            // render:keep_unmodified_copy and other conditions that trigger MRT for screen sharing expect a work buffer with sRGB primaries
+            .primariesNamed = NColorManagement::CM_PRIMARIES_SRGB,
+            .primaries      = NColorPrimaries::BT709,
         });
 
     return m_cachedInternalDescription;
diff --git a/src/helpers/Monitor.hpp b/src/helpers/Monitor.hpp
index 478d3fedb..8d26be45b 100644
--- a/src/helpers/Monitor.hpp
+++ b/src/helpers/Monitor.hpp
@@ -415,7 +415,7 @@ class CMonitor {
 
     // Resources
     UP<Monitor::CMonitorResources> m_resources;
-    // cached should contain one of predefined descriptions: BT2020 primaries with variable TF and SDR luminances or SRGB primaries with linear TF and variable luminances.
+    // cached should contain one of predefined descriptions for FP16: sRGB primaries with either linear TF by default and in HDR mode or monitor's TF in SDR with render:fp16_sdr_tf = 2
     // avoids lookup for an id when ::from is used
     NColorManagement::PImageDescription m_cachedInternalDescription = NColorManagement::CImageDescription::from(NColorManagement::SImageDescription{});