[v3,09/14] libcamera: ipa: simple: Make gamma adjustable
diff mbox series

Message ID 20260114113016.25162-10-mzamazal@redhat.com
State New
Headers show
Series
  • Simple pipeline IPA cleanup
Related show

Commit Message

Milan Zamazal Jan. 14, 2026, 11:30 a.m. UTC 
The gamma value is fixed in software ISP.  Let's make it adjustable,
similarly to contrast and saturation.

Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
---
 src/ipa/simple/algorithms/adjust.cpp |  8 ++++++++
 src/ipa/simple/algorithms/adjust.h   |  2 ++
 src/ipa/simple/algorithms/lut.cpp    | 12 +++++++-----
 src/ipa/simple/ipa_context.h         |  4 +++-
 4 files changed, 20 insertions(+), 6 deletions(-)

Patch
diff mbox series 

diff --git a/src/ipa/simple/algorithms/adjust.cpp b/src/ipa/simple/algorithms/adjust.cpp
index 27ae2a53a..cfbc39610 100644
--- a/src/ipa/simple/algorithms/adjust.cpp
+++ b/src/ipa/simple/algorithms/adjust.cpp
@@ -23,6 +23,7 @@  LOG_DEFINE_CATEGORY(IPASoftAdjust)
 
 int Adjust::init(IPAContext &context, [[maybe_unused]] const YamlObject &tuningData)
 {
+	context.ctrlMap[&controls::Gamma] = ControlInfo(0.1f, 10.0f, kDefaultGamma);
 	context.ctrlMap[&controls::Contrast] = ControlInfo(0.0f, 2.0f, 1.0f);
 	if (context.ccmEnabled)
 		context.ctrlMap[&controls::Saturation] = ControlInfo(0.0f, 2.0f, 1.0f);
@@ -32,6 +33,7 @@  int Adjust::init(IPAContext &context, [[maybe_unused]] const YamlObject &tuningD
 int Adjust::configure(IPAContext &context,
 		      [[maybe_unused]] const IPAConfigInfo &configInfo)
 {
+	context.activeState.knobs.gamma = std::optional<double>();
 	context.activeState.knobs.contrast = std::optional<double>();
 	context.activeState.knobs.saturation = std::optional<double>();
 
@@ -43,6 +45,12 @@  void Adjust::queueRequest(typename Module::Context &context,
 			  [[maybe_unused]] typename Module::FrameContext &frameContext,
 			  const ControlList &controls)
 {
+	const auto &gamma = controls.get(controls::Gamma);
+	if (gamma.has_value()) {
+		context.activeState.knobs.gamma = gamma;
+		LOG(IPASoftAdjust, Debug) << "Setting gamma to " << gamma.value();
+	}
+
 	const auto &contrast = controls.get(controls::Contrast);
 	if (contrast.has_value()) {
 		context.activeState.knobs.contrast = contrast;
diff --git a/src/ipa/simple/algorithms/adjust.h b/src/ipa/simple/algorithms/adjust.h
index c4baa2503..190d2079f 100644
--- a/src/ipa/simple/algorithms/adjust.h
+++ b/src/ipa/simple/algorithms/adjust.h
@@ -19,6 +19,8 @@  namespace libcamera {
 
 namespace ipa::soft::algorithms {
 
+const float kDefaultGamma = 2.2f;
+
 class Adjust : public Algorithm
 {
 public:
diff --git a/src/ipa/simple/algorithms/lut.cpp b/src/ipa/simple/algorithms/lut.cpp
index 3a00bf4ee..25b188b91 100644
--- a/src/ipa/simple/algorithms/lut.cpp
+++ b/src/ipa/simple/algorithms/lut.cpp
@@ -18,6 +18,8 @@ 
 
 #include "simple/ipa_context.h"
 
+#include "adjust.h"
+
 namespace libcamera {
 
 LOG_DEFINE_CATEGORY(IPASoftLut)
@@ -27,8 +29,6 @@  namespace ipa::soft::algorithms {
 int Lut::configure(IPAContext &context,
 		   [[maybe_unused]] const IPAConfigInfo &configInfo)
 {
-	/* Gamma value is fixed */
-	context.configuration.gamma = 1.0 / 2.2;
 	updateGammaTable(context);
 
 	return 0;
@@ -37,6 +37,8 @@  int Lut::configure(IPAContext &context,
 void Lut::updateGammaTable(IPAContext &context)
 {
 	const auto blackLevel = context.activeState.blc.level;
+	const auto gamma =
+		1.0 / context.activeState.knobs.gamma.value_or(kDefaultGamma);
 	const auto contrast = context.activeState.knobs.contrast.value_or(1.0);
 	/* Convert 0..2 to 0..infinity; avoid actual inifinity at tan(pi/2) */
 	double contrastExp = tan(std::clamp(contrast * M_PI_4, 0.0, M_PI_2 - 0.00001));
@@ -52,8 +54,7 @@  void Lut::updateGammaTable(IPAContext &context)
 				normalized = 0.5 * std::pow(normalized / 0.5, contrastExp);
 			else
 				normalized = 1.0 - 0.5 * std::pow((1.0 - normalized) / 0.5, contrastExp);
-			gammaTable[i] = UINT8_MAX *
-					std::pow(normalized, context.configuration.gamma);
+			gammaTable[i] = UINT8_MAX * std::pow(normalized, gamma);
 		}
 		/*
 		 * Due to CCM operations, the table lookup may reach indices below the black
@@ -65,6 +66,7 @@  void Lut::updateGammaTable(IPAContext &context)
 			  gammaTable[blackIndex]);
 	}
 
+	context.activeState.gamma.gamma = gamma;
 	context.activeState.gamma.blackLevel = blackLevel;
 	context.activeState.gamma.contrastExp = contrastExp;
 }
@@ -131,7 +133,7 @@  void Lut::prepare(IPAContext &context,
 		context.activeState.matrixChanged = false;
 	}
 
-	params->gamma = context.configuration.gamma;
+	params->gamma = context.activeState.gamma.gamma;
 	params->contrastExp = context.activeState.gamma.contrastExp;
 }
 
diff --git a/src/ipa/simple/ipa_context.h b/src/ipa/simple/ipa_context.h
index 58dcad290..680b72eb9 100644
--- a/src/ipa/simple/ipa_context.h
+++ b/src/ipa/simple/ipa_context.h
@@ -25,7 +25,6 @@  namespace libcamera {
 namespace ipa::soft {
 
 struct IPASessionConfiguration {
-	float gamma;
 	struct {
 		int32_t exposureMin, exposureMax;
 		double againMin, againMax, again10, againMinStep;
@@ -58,6 +57,7 @@  struct IPAActiveState {
 	struct {
 		std::array<double, kGammaLookupSize> gammaTable;
 		uint8_t blackLevel;
+		float gamma;
 		double contrast;
 		double contrastExp;
 	} gamma;
@@ -67,6 +67,7 @@  struct IPAActiveState {
 	bool matrixChanged = false;
 
 	struct {
+		std::optional<float> gamma;
 		/* 0..2 range, 1.0 = normal */
 		std::optional<double> contrast;
 		std::optional<float> saturation;
@@ -86,6 +87,7 @@  struct IPAFrameContext : public FrameContext {
 		double blue;
 	} gains;
 
+	std::optional<float> gamma;
 	std::optional<double> contrast;
 	std::optional<float> saturation;
 };