libipa: awb: Make result of gainsFromColourTemp optional

In the grey world AWB case, if no colour gains are contained in the
tuning file, the colour gains get reset to 1 when the colour temperature
is set manually. This is unexpected and undesirable. Allow the
gainsFromColourTemp() function to return a std::nullopt to handle that
case.

While at it, remove an unnecessary import from rkisp1/algorithms/awb.h.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/ipa/libipa/awb_bayes.cpp b/src/ipa/libipa/awb_bayes.cpp
index d1d0eaf0..d2bcbd83 100644
--- a/src/ipa/libipa/awb_bayes.cpp
+++ b/src/ipa/libipa/awb_bayes.cpp
@@ -270,7 +270,7 @@ void AwbBayes::handleControls(const ControlList &controls)
 	}
 }
 
-RGB<double> AwbBayes::gainsFromColourTemperature(double colourTemperature)
+std::optional<RGB<double>> AwbBayes::gainsFromColourTemperature(double colourTemperature)
 {
 	/*
 	 * \todo In the RaspberryPi code, the ct curve was interpolated in
@@ -278,7 +278,7 @@ RGB<double> AwbBayes::gainsFromColourTemperature(double colourTemperature)
 	 * intuitive, as the gains are in linear space. But I can't prove it.
 	 */
 	const auto &gains = colourGainCurve_.getInterpolated(colourTemperature);
-	return { { gains[0], 1.0, gains[1] } };
+	return RGB<double>{ { gains[0], 1.0, gains[1] } };
 }
 
 AwbResult AwbBayes::calculateAwb(const AwbStats &stats, unsigned int lux)