ipa: libipa: colour: Use the RGB class to model RGB values

The rec601LuminanceFromRGB() and estimateCCT() functions take RGB
triplets as three variables. Replace them with instances of the RGB
class and adapt the users accordingly. Only variables passed directly to
these functions are converted to RGB instances, further conversion of
IPA modules to the RGB class will be performed separately.

While at it, fix a typo in the documentation of the estimateCCT()
function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>

1 files changed, 10 insertions, 11 deletions

diff --git a/src/ipa/rpi/controller/rpi/agc_channel.cpp b/src/ipa/rpi/controller/rpi/agc_channel.cpp
index 14335943..79c45973 100644
--- a/src/ipa/rpi/controller/rpi/agc_channel.cpp
+++ b/src/ipa/rpi/controller/rpi/agc_channel.cpp
@@ -13,6 +13,7 @@
 #include <libcamera/base/log.h>
 
 #include "libipa/colours.h"
+#include "libipa/vector.h"
 
 #include "../awb_status.h"
 #include "../device_status.h"
@@ -681,12 +682,13 @@ static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
 	 * 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;
+	ipa::RGB<double> sum{ 0.0 };
+	double pixelSum = 0;
 	for (unsigned int i = 0; i < stats->agcRegions.numRegions(); i++) {
 		auto &region = stats->agcRegions.get(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);
+		sum.r() += std::min<double>(region.val.rSum * gain, (maxVal - 1) * region.counted);
+		sum.g() += std::min<double>(region.val.gSum * gain, (maxVal - 1) * region.counted);
+		sum.b() += std::min<double>(region.val.bSum * gain, (maxVal - 1) * region.counted);
 		pixelSum += region.counted;
 	}
 	if (pixelSum == 0.0) {
@@ -694,14 +696,11 @@ static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
 		return 0;
 	}
 
-	double ySum;
 	/* Factor in the AWB correction if needed. */
-	if (stats->agcStatsPos == Statistics::AgcStatsPos::PreWb) {
-		ySum = ipa::rec601LuminanceFromRGB(rSum * awb.gainR,
-						   gSum * awb.gainG,
-						   bSum * awb.gainB);
-	} else
-		ySum = ipa::rec601LuminanceFromRGB(rSum, gSum, bSum);
+	if (stats->agcStatsPos == Statistics::AgcStatsPos::PreWb)
+		sum *= ipa::RGB<double>{{ awb.gainR, awb.gainR, awb.gainB }};
+
+	double ySum = ipa::rec601LuminanceFromRGB(sum);
 
 	return ySum / pixelSum / (1 << 16);
 }