ipa: rkisp1: Derive rkisp1::algorithms::Agc from AgcMeanLuminance

Now that we have a AgcMeanLuminance class that centralises our AEGC
algorithm, derive the RkISP1's Agc class from it and plumb in the
necessary framework to enable it to be used. For simplicities sake
this commit switches the algorithm to use the derived class, but
does not remove the bespoke functions at this time.

Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

2 files changed, 84 insertions, 6 deletions

diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
index 47a6f7b2..f8d1b9a3 100644
--- a/src/ipa/rkisp1/algorithms/agc.cpp
+++ b/src/ipa/rkisp1/algorithms/agc.cpp
@@ -65,6 +65,29 @@ Agc::Agc()
 }
 
 /**
+ * \brief Initialise the AGC algorithm from tuning files
+ * \param[in] context The shared IPA context
+ * \param[in] tuningData The YamlObject containing Agc tuning data
+ *
+ * This function calls the base class' tuningData parsers to discover which
+ * control values are supported.
+ *
+ * \return 0 on success or errors from the base class
+ */
+int Agc::init(IPAContext &context, const YamlObject &tuningData)
+{
+	int ret;
+
+	ret = parseTuningData(tuningData);
+	if (ret)
+		return ret;
+
+	context.ctrlMap.merge(controls());
+
+	return 0;
+}
+
+/**
  * \brief Configure the AGC given a configInfo
  * \param[in] context The shared IPA context
  * \param[in] configInfo The IPA configuration data
@@ -81,6 +104,9 @@ int Agc::configure(IPAContext &context, const IPACameraSensorInfo &configInfo)
 	context.activeState.agc.manual.exposure = context.activeState.agc.automatic.exposure;
 	context.activeState.agc.autoEnabled = !context.configuration.raw;
 
+	context.activeState.agc.constraintMode = constraintModes().begin()->first;
+	context.activeState.agc.exposureMode = exposureModeHelpers().begin()->first;
+
 	/*
 	 * Define the measurement window for AGC as a centered rectangle
 	 * covering 3/4 of the image width and height.
@@ -95,6 +121,15 @@ int Agc::configure(IPAContext &context, const IPACameraSensorInfo &configInfo)
 	 * frame index
 	 */
 	frameCount_ = 0;
+
+	/* \todo Run this again when FrameDurationLimits is passed in */
+	setLimits(context.configuration.sensor.minShutterSpeed,
+		  context.configuration.sensor.maxShutterSpeed,
+		  context.configuration.sensor.minAnalogueGain,
+		  context.configuration.sensor.maxAnalogueGain);
+
+	resetFrameCount();
+
 	return 0;
 }
 
@@ -234,7 +269,6 @@ void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
 			  double yGain, double iqMeanGain)
 {
 	IPASessionConfiguration &configuration = context.configuration;
-	IPAActiveState &activeState = context.activeState;
 
 	/* Get the effective exposure and gain applied on the sensor. */
 	uint32_t exposure = frameContext.sensor.exposure;
@@ -300,10 +334,6 @@ void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
 	LOG(RkISP1Agc, Debug) << "Divided up shutter and gain are "
 			      << shutterTime << " and "
 			      << stepGain;
-
-	/* Update the estimated exposure and gain. */
-	activeState.agc.automatic.exposure = shutterTime / configuration.sensor.lineDuration;
-	activeState.agc.automatic.gain = stepGain;
 }
 
 /**
@@ -373,6 +403,19 @@ void Agc::fillMetadata(IPAContext &context, IPAFrameContext &frameContext,
 	metadata.set(controls::FrameDuration, frameDuration.get<std::micro>());
 }
 
+double Agc::estimateLuminance(double gain) const
+{
+	double ySum = 0.0;
+
+	/* Sum the averages, saturated to 255. */
+	for (uint8_t expMean : expMeans_)
+		ySum += std::min(expMean * gain, 255.0);
+
+	/* \todo Weight with the AWB gains */
+
+	return ySum / expMeans_.size() / 255;
+}
+
 /**
  * \brief Process RkISP1 statistics, and run AGC operations
  * \param[in] context The shared IPA context
@@ -438,7 +481,35 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
 	computeExposure(context, frameContext, yGain, iqMeanGain);
 	frameCount_++;
 
+	expMeans_ = { params->ae.exp_mean, context.hw->numAeCells };
+
+	/*
+	 * The Agc algorithm needs to know the effective exposure value that was
+	 * applied to the sensor when the statistics were collected.
+	 */
+	utils::Duration exposureTime = context.configuration.sensor.lineDuration
+				       * frameContext.sensor.exposure;
+	double analogueGain = frameContext.sensor.gain;
+	utils::Duration effectiveExposureValue = exposureTime * analogueGain;
+
+	utils::Duration shutterTime;
+	double aGain, dGain;
+	std::tie(shutterTime, aGain, dGain) =
+		calculateNewEv(context.activeState.agc.constraintMode,
+			       context.activeState.agc.exposureMode,
+			       Histogram(hist), effectiveExposureValue);
+
+	LOG(RkISP1Agc, Debug)
+		<< "Divided up shutter, analogue gain and digital gain are "
+		<< shutterTime << ", " << aGain << " and " << dGain;
+
+	IPAActiveState &activeState = context.activeState;
+	/* Update the estimated exposure and gain. */
+	activeState.agc.automatic.exposure = shutterTime / context.configuration.sensor.lineDuration;
+	activeState.agc.automatic.gain = aGain;
+
 	fillMetadata(context, frameContext, metadata);
+	expMeans_ = {};
 }
 
 REGISTER_IPA_ALGORITHM(Agc, "Agc")
diff --git a/src/ipa/rkisp1/algorithms/agc.h b/src/ipa/rkisp1/algorithms/agc.h
index fb82a33f..34504459 100644
--- a/src/ipa/rkisp1/algorithms/agc.h
+++ b/src/ipa/rkisp1/algorithms/agc.h
@@ -14,18 +14,22 @@
 
 #include <libcamera/geometry.h>
 
+#include "libipa/agc_mean_luminance.h"
+#include "libipa/histogram.h"
+
 #include "algorithm.h"
 
 namespace libcamera {
 
 namespace ipa::rkisp1::algorithms {
 
-class Agc : public Algorithm
+class Agc : public Algorithm, public AgcMeanLuminance
 {
 public:
 	Agc();
 	~Agc() = default;
 
+	int init(IPAContext &context, const YamlObject &tuningData) override;
 	int configure(IPAContext &context, const IPACameraSensorInfo &configInfo) override;
 	void queueRequest(IPAContext &context,
 			  const uint32_t frame,
@@ -47,10 +51,13 @@ private:
 	double measureBrightness(Span<const uint32_t> hist) const;
 	void fillMetadata(IPAContext &context, IPAFrameContext &frameContext,
 			  ControlList &metadata);
+	double estimateLuminance(double gain) const override;
 
 	uint64_t frameCount_;
 
 	utils::Duration filteredExposure_;
+
+	Span<const uint8_t> expMeans_;
 };
 
 } /* namespace ipa::rkisp1::algorithms */