ipa: rpi: agc: Use channel constraints in the AGC algorithm

Whenever we run Agc::process(), we store the most recent total
exposure requested for each channel.

With these values we can apply the channel constraints after
time-filtering the requested total exposure, but before working out
how much digital gain is needed.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/src/ipa/rpi/controller/rpi/agc_channel.h b/src/ipa/rpi/controller/rpi/agc_channel.h
index ceaab12f..ae826fa8 100644
--- a/src/ipa/rpi/controller/rpi/agc_channel.h
+++ b/src/ipa/rpi/controller/rpi/agc_channel.h
@@ -21,6 +21,8 @@
 
 namespace RPiController {
 
+using AgcChannelTotalExposures = std::vector<libcamera::utils::Duration>;
+
 struct AgcMeteringMode {
 	std::vector<double> weights;
 	int read(const libcamera::YamlObject &params);
@@ -95,7 +97,8 @@ public:
 	void disableAuto();
 	void switchMode(CameraMode const &cameraMode, Metadata *metadata);
 	void prepare(Metadata *imageMetadata);
-	void process(StatisticsPtr &stats, DeviceStatus const &deviceStatus, Metadata *imageMetadata);
+	void process(StatisticsPtr &stats, DeviceStatus const &deviceStatus, Metadata *imageMetadata,
+		     const AgcChannelTotalExposures &channelTotalExposures);
 
 private:
 	bool updateLockStatus(DeviceStatus const &deviceStatus);
@@ -107,7 +110,8 @@ private:
 			 double &gain, double &targetY);
 	void computeTargetExposure(double gain);
 	void filterExposure();
-	bool applyDigitalGain(double gain, double targetY);
+	bool applyChannelConstraints(const AgcChannelTotalExposures &channelTotalExposures);
+	bool applyDigitalGain(double gain, double targetY, bool channelBound);
 	void divideUpExposure();
 	void writeAndFinish(Metadata *imageMetadata, bool desaturate);
 	libcamera::utils::Duration limitShutter(libcamera::utils::Duration shutter);