[libcamera-devel] [PATCH 10/20] ipa: rpi: Prepare AWB for PiSP support

[Naushir Patuck]

Prepare the AWB algorithm to support the PiSP hardware. The key change
is to factor in the LS correction in the AWB zone statistics. This is
different from VC4 where the LS correction happens before statistics
gathering.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
---
 src/ipa/rpi/controller/rpi/awb.cpp | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/ipa/rpi/controller/rpi/awb.cpp b/src/ipa/rpi/controller/rpi/awb.cpp
index ef3435d66106..5ae0c2fad6e9 100644
--- a/src/ipa/rpi/controller/rpi/awb.cpp
+++ b/src/ipa/rpi/controller/rpi/awb.cpp
@@ -12,6 +12,7 @@
 
 #include "../lux_status.h"
 
+#include "alsc_status.h"
 #include "awb.h"
 
 using namespace RPiController;
@@ -398,18 +399,28 @@ void Awb::asyncFunc()
 }
 
 static void generateStats(std::vector<Awb::RGB> &zones,
-			  RgbyRegions &stats, double minPixels,
-			  double minG)
+			  StatisticsPtr &stats, double minPixels,
+			  double minG, Metadata &globalMetadata)
 {
-	for (auto const &region : stats) {
+	std::scoped_lock<RPiController::Metadata> l(globalMetadata);
+
+	for (unsigned int i = 0; i < stats->awbRegions.numRegions(); i++) {
 		Awb::RGB zone;
+		auto &region = stats->awbRegions.get(i);
 		if (region.counted >= minPixels) {
 			zone.G = region.val.gSum / region.counted;
-			if (zone.G >= minG) {
-				zone.R = region.val.rSum / region.counted;
-				zone.B = region.val.bSum / region.counted;
-				zones.push_back(zone);
+			if (zone.G < minG)
+				continue;
+			zone.R = region.val.rSum / region.counted;
+			zone.B = region.val.bSum / region.counted;
+			/* Factor in the ALSC applied colour shading correction if required. */
+			const AlscStatus *alscStatus = globalMetadata.getLocked<AlscStatus>("alsc.status");
+			if (stats->colourStatsPos == Statistics::ColourStatsPos::PreLsc && alscStatus) {
+				zone.R *= alscStatus->r[i];
+				zone.G *= alscStatus->g[i];
+				zone.B *= alscStatus->b[i];
 			}
+			zones.push_back(zone);
 		}
 	}
 }
@@ -421,8 +432,8 @@ void Awb::prepareStats()
 	 * LSC has already been applied to the stats in this pipeline, so stop
 	 * any LSC compensation.  We also ignore config_.fast in this version.
 	 */
-	generateStats(zones_, statistics_->awbRegions, config_.minPixels,
-		      config_.minG);
+	generateStats(zones_, statistics_, config_.minPixels,
+		      config_.minG, getGlobalMetadata());
 	/*
 	 * apply sensitivities, so values appear to come from our "canonical"
 	 * sensor.
-- 
2.34.1