[libcamera-devel] [PATCH v3 08/10] ipa: raspberrypi: Generalise the agc algorithm

[Naushir Patuck]

Remove any hard-coded assumptions about the target hardware platform
from the AGC algorithm. Instead, use the "target" string provided by
the camera tuning config and generalised statistics structures to
determing parameters such as grid and region sizes.

This change replaces all hard-coded arrays with equivalent std::vector
types.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 src/ipa/raspberrypi/controller/rpi/agc.cpp | 20 +++++++++++++-------
 src/ipa/raspberrypi/controller/rpi/agc.h   |  9 +--------
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index f438cab8840a..e6fb7b8dbeb3 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -31,17 +31,12 @@ LOG_DEFINE_CATEGORY(RPiAgc)
 int AgcMeteringMode::read(const libcamera::YamlObject &params)
 {
 	const YamlObject &yamlWeights = params["weights"];
-	if (yamlWeights.size() != AgcStatsSize) {
-		LOG(RPiAgc, Error) << "AgcMeteringMode: Incorrect number of weights";
-		return -EINVAL;
-	}
 
-	unsigned int num = 0;
 	for (const auto &p : yamlWeights.asList()) {
 		auto value = p.get<double>();
 		if (!value)
 			return -EINVAL;
-		weights[num++] = *value;
+		weights.push_back(*value);
 	}
 
 	return 0;
@@ -248,6 +243,14 @@ int Agc::read(const libcamera::YamlObject &params)
 	if (ret)
 		return ret;
 
+	const Size &size = getHardwareConfig().agcZoneWeights;
+	for (auto const &modes : config_.meteringModes) {
+		if (modes.second.weights.size() != size.width * size.height) {
+			LOG(RPiAgc, Error) << "AgcMeteringMode: Incorrect number of weights";
+			return -EINVAL;
+		}
+	}
+
 	/*
 	 * Set the config's defaults (which are the first ones it read) as our
 	 * current modes, until someone changes them.  (they're all known to
@@ -585,9 +588,12 @@ void Agc::fetchAwbStatus(Metadata *imageMetadata)
 }
 
 static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
-			      double weights[], double gain)
+			      std::vector<double> &weights, double gain)
 {
 	constexpr uint64_t maxVal = 1 << Statistics::NormalisationFactorPow2;
+
+	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).
diff --git a/src/ipa/raspberrypi/controller/rpi/agc.h b/src/ipa/raspberrypi/controller/rpi/agc.h
index 4fa9b8de5fb2..4e5f272fac78 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.h
+++ b/src/ipa/raspberrypi/controller/rpi/agc.h
@@ -17,17 +17,10 @@
 
 /* This is our implementation of AGC. */
 
-/*
- * This is the number actually set up by the firmware, not the maximum possible
- * number (which is 16).
- */
-
-constexpr unsigned int AgcStatsSize = 15;
-
 namespace RPiController {
 
 struct AgcMeteringMode {
-	double weights[AgcStatsSize];
+	std::vector<double> weights;
 	int read(const libcamera::YamlObject &params);
 };
 
-- 
2.34.1