[libcamera-devel] [PATCH 10/13] ipa: raspberrypi: agc: Move weights out of AGC

[Naushir Patuck]

From: David Plowman <david.plowman at raspberrypi.com>

The region weights for the the AGC zones are handled by the AGC
algorithm. Apply them directly in the IPA (vc4.cpp) to the statistics
that we pass to the AGC.

Signed-off-by: David Plowman <david.plowman at raspberrypi>
Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
---
 src/ipa/rpi/controller/agc_algorithm.h |  3 +++
 src/ipa/rpi/controller/rpi/agc.cpp     | 27 +++++++++++++++++---------
 src/ipa/rpi/controller/rpi/agc.h       |  1 +
 src/ipa/rpi/vc4/vc4.cpp                | 26 ++++++++++++++++++-------
 4 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/src/ipa/rpi/controller/agc_algorithm.h b/src/ipa/rpi/controller/agc_algorithm.h
index 36e6c11058ee..b6949daa7135 100644
--- a/src/ipa/rpi/controller/agc_algorithm.h
+++ b/src/ipa/rpi/controller/agc_algorithm.h
@@ -6,6 +6,8 @@
  */
 #pragma once
 
+#include <vector>
+
 #include <libcamera/base/utils.h>
 
 #include "algorithm.h"
@@ -18,6 +20,7 @@ public:
 	AgcAlgorithm(Controller *controller) : Algorithm(controller) {}
 	/* An AGC algorithm must provide the following: */
 	virtual unsigned int getConvergenceFrames() const = 0;
+	virtual std::vector<double> const &getWeights() const = 0;
 	virtual void setEv(double ev) = 0;
 	virtual void setFlickerPeriod(libcamera::utils::Duration flickerPeriod) = 0;
 	virtual void setFixedShutter(libcamera::utils::Duration fixedShutter) = 0;
diff --git a/src/ipa/rpi/controller/rpi/agc.cpp b/src/ipa/rpi/controller/rpi/agc.cpp
index e6fb7b8dbeb3..e79c82e2e65b 100644
--- a/src/ipa/rpi/controller/rpi/agc.cpp
+++ b/src/ipa/rpi/controller/rpi/agc.cpp
@@ -292,6 +292,18 @@ unsigned int Agc::getConvergenceFrames() const
 		return config_.convergenceFrames;
 }
 
+std::vector<double> const &Agc::getWeights() const
+{
+	/*
+	 * In case someone calls setMeteringMode and then this before the
+	 * algorithm has run and updated the meteringMode_ pointer.
+	 */
+	auto it = config_.meteringModes.find(meteringModeName_);
+	if (it == config_.meteringModes.end())
+		return meteringMode_->weights;
+	return it->second.weights;
+}
+
 void Agc::setEv(double ev)
 {
 	ev_ = ev;
@@ -595,19 +607,16 @@ static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
 	ASSERT(weights.size() == stats->agcRegions.numRegions());
 
 	/*
-	 * Note how the calculation below means that equal weights give you
-	 * "average" metering (i.e. all pixels equally important).
+	 * Note that the weights are applied by the IPA to the statistics directly,
+	 * before they are given to us here.
 	 */
 	double rSum = 0, gSum = 0, bSum = 0, pixelSum = 0;
 	for (unsigned int i = 0; i < stats->agcRegions.numRegions(); i++) {
 		auto &region = stats->agcRegions.get(i);
-		double rAcc = std::min<double>(region.val.rSum * gain, (maxVal - 1) * region.counted);
-		double gAcc = std::min<double>(region.val.gSum * gain, (maxVal - 1) * region.counted);
-		double bAcc = std::min<double>(region.val.bSum * gain, (maxVal - 1) * region.counted);
-		rSum += rAcc * weights[i];
-		gSum += gAcc * weights[i];
-		bSum += bAcc * weights[i];
-		pixelSum += region.counted * weights[i];
+		rSum += std::min<double>(region.val.rSum * gain, (maxVal - 1) * region.counted);
+		gSum += std::min<double>(region.val.gSum * gain, (maxVal - 1) * region.counted);
+		bSum += std::min<double>(region.val.bSum * gain, (maxVal - 1) * region.counted);
+		pixelSum += region.counted;
 	}
 	if (pixelSum == 0.0) {
 		LOG(RPiAgc, Warning) << "computeInitialY: pixelSum is zero";
diff --git a/src/ipa/rpi/controller/rpi/agc.h b/src/ipa/rpi/controller/rpi/agc.h
index 4e5f272fac78..939f97295a02 100644
--- a/src/ipa/rpi/controller/rpi/agc.h
+++ b/src/ipa/rpi/controller/rpi/agc.h
@@ -69,6 +69,7 @@ public:
 	char const *name() const override;
 	int read(const libcamera::YamlObject &params) override;
 	unsigned int getConvergenceFrames() const override;
+	std::vector<double> const &getWeights() const override;
 	void setEv(double ev) override;
 	void setFlickerPeriod(libcamera::utils::Duration flickerPeriod) override;
 	void setMaxShutter(libcamera::utils::Duration maxShutter) override;
diff --git a/src/ipa/rpi/vc4/vc4.cpp b/src/ipa/rpi/vc4/vc4.cpp
index a32db9bcaf9a..e38024ac5418 100644
--- a/src/ipa/rpi/vc4/vc4.cpp
+++ b/src/ipa/rpi/vc4/vc4.cpp
@@ -211,13 +211,25 @@ RPiController::StatisticsPtr IpaVc4::platformProcessStats(Span<uint8_t> mem)
 						stats->awb_stats[i].counted,
 						stats->awb_stats[i].notcounted });
 
-	statistics->agcRegions.init(hw.agcRegions);
-	for (i = 0; i < statistics->agcRegions.numRegions(); i++)
-		statistics->agcRegions.set(i, { { stats->agc_stats[i].r_sum << scale,
-						  stats->agc_stats[i].g_sum << scale,
-						  stats->agc_stats[i].b_sum << scale },
-						stats->agc_stats[i].counted,
-						stats->awb_stats[i].notcounted });
+	RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+		controller_.getAlgorithm("agc"));
+	if (!agc) {
+		LOG(IPARPI, Debug) << "No AGC algorithm - not copying statistics";
+		statistics->agcRegions.init(0);
+	} else {
+		statistics->agcRegions.init(hw.agcRegions);
+		const std::vector<double> &weights = agc->getWeights();
+		for (i = 0; i < statistics->agcRegions.numRegions(); i++) {
+			uint64_t rSum = (stats->agc_stats[i].r_sum << scale) * weights[i];
+			uint64_t gSum = (stats->agc_stats[i].g_sum << scale) * weights[i];
+			uint64_t bSum = (stats->agc_stats[i].b_sum << scale) * weights[i];
+			uint32_t counted = stats->agc_stats[i].counted * weights[i];
+			uint32_t notcounted = stats->agc_stats[i].notcounted * weights[i];
+			statistics->agcRegions.set(i, { { rSum, gSum, bSum },
+							counted,
+							notcounted });
+		}
+	}
 
 	statistics->focusRegions.init(hw.focusRegions);
 	for (i = 0; i < statistics->focusRegions.numRegions(); i++)
-- 
2.34.1