[libcamera-devel] [PATCH v2 09/20] ipa: rpi: Prepare ALSC for PiSP support

[Naushir Patuck]

Prepare the ALSC algorithm to support the PiSP hardware. The key change
is to avoid factoring out the WB correction in the AWB zone statistics.

Add the ALSC correction to the global metadata so that AWB can use it to
factor the gains back in for the AWB calculations.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
---
 src/ipa/rpi/controller/rpi/alsc.cpp | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/ipa/rpi/controller/rpi/alsc.cpp b/src/ipa/rpi/controller/rpi/alsc.cpp
index 3a2e8fe00ca6..f1ccef87c70c 100644
--- a/src/ipa/rpi/controller/rpi/alsc.cpp
+++ b/src/ipa/rpi/controller/rpi/alsc.cpp
@@ -348,9 +348,11 @@ static void copyStats(RgbyRegions &regions, StatisticsPtr &stats,
 	const std::vector<double> &bTable = status.b;
 	for (unsigned int i = 0; i < stats->awbRegions.numRegions(); i++) {
 		auto r = stats->awbRegions.get(i);
-		r.val.rSum = static_cast<uint64_t>(r.val.rSum / rTable[i]);
-		r.val.gSum = static_cast<uint64_t>(r.val.gSum / gTable[i]);
-		r.val.bSum = static_cast<uint64_t>(r.val.bSum / bTable[i]);
+		if (stats->colourStatsPos == Statistics::ColourStatsPos::PostLsc) {
+			r.val.rSum = static_cast<uint64_t>(r.val.rSum / rTable[i]);
+			r.val.gSum = static_cast<uint64_t>(r.val.gSum / gTable[i]);
+			r.val.bSum = static_cast<uint64_t>(r.val.bSum / bTable[i]);
+		}
 		regions.set(i, r);
 	}
 }
@@ -368,7 +370,8 @@ void Alsc::restartAsync(StatisticsPtr &stats, Metadata *imageMetadata)
 	 * the LSC table that the pipeline applied to them.
 	 */
 	AlscStatus alscStatus;
-	if (imageMetadata->get("alsc.status", alscStatus) != 0) {
+	if (stats->colourStatsPos == Statistics::ColourStatsPos::PostLsc &&
+	    imageMetadata->get("alsc.status", alscStatus) != 0) {
 		LOG(RPiAlsc, Warning)
 			<< "No ALSC status found for applied gains!";
 		alscStatus.r.resize(config_.tableSize.width * config_.tableSize.height, 1.0);
@@ -414,6 +417,11 @@ void Alsc::prepare(Metadata *imageMetadata)
 	status.g = prevSyncResults_[1].data();
 	status.b = prevSyncResults_[2].data();
 	imageMetadata->set("alsc.status", status);
+	/*
+	 * Put the results in the global metadata as well. This will be used by
+	 * AWB to factor in the colour shading correction.
+	 */
+	getGlobalMetadata().set("alsc.status", status);
 }
 
 void Alsc::process(StatisticsPtr &stats, Metadata *imageMetadata)
-- 
2.34.1