ipa: raspberrypi: agc: Move weights out of AGC

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@raspberrypi.com>
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

3 files changed, 22 insertions, 9 deletions

diff --git a/src/ipa/rpi/controller/agc_algorithm.h b/src/ipa/rpi/controller/agc_algorithm.h
index 36e6c110..b6949daa 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 e6fb7b8d..e79c82e2 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 4e5f272f..939f9729 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;