3 files changed, 189 insertions, 0 deletions
diff --git a/src/ipa/libipa/awb.cpp b/src/ipa/libipa/awb.cpp
new file mode 100644
index 00000000..4db97f6a
--- /dev/null
+++ b/src/ipa/libipa/awb.cpp
@@ -0,0 +1,137 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024 Ideas on Board Oy
+ *
+ * Generic AWB algorithms
+ */
+
+#include "awb.h"
+
+#include <libcamera/base/log.h>
+
+/**
+ * \file awb.h
+ * \brief Base classes for AWB algorithms
+ */
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(Awb)
+
+namespace ipa {
+
+/**
+ * \class AwbResult
+ * \brief The result of an awb calculation
+ *
+ * This class holds the result of an auto white balance calculation.
+ */
+
+/**
+ * \var AwbResult::gains
+ * \brief The calculated white balance gains
+ */
+
+/**
+ * \var AwbResult::colourTemperature
+ * \brief The calculated colour temperature in Kelvin
+ */
+
+/**
+ * \class AwbStats
+ * \brief An abstraction class wrapping hardware-specific AWB statistics
+ *
+ * Pipeline handlers using an AWB algorithm based on the AwbAlgorithm class need
+ * to implement this class to give the algorithm access to the hardware-specific
+ * statistics data.
+ */
+
+/**
+ * \fn AwbStats::computeColourError
+ * \brief Compute an error value for when the given gains would be applied
+ * \param[in] gains The gains to apply
+ *
+ * Compute an error value (non-greyness) assuming the given \a gains would be
+ * applied. To keep the actual implementations computationally inexpensive,
+ * the squared colour error shall be returned.
+ *
+ * If the awb statistics provide multiple zones, the sum over all zones needs to
+ * calculated.
+ *
+ * \return The computed error value
+ */
+
+/**
+ * \fn AwbStats::getRGBMeans
+ * \brief Get RGB means of the statistics
+ *
+ * Fetch the RGB means from the statistics. The values of each channel are
+ * dimensionless and only the ratios are used for further calculations. This is
+ * used by the simple gray world model to calculate the gains to apply.
+ *
+ * \return The RGB means
+ */
+
+/**
+ * \class AwbAlgorithm
+ * \brief A base class for auto white balance algorithms
+ *
+ * This class is a base class for auto white balance algorithms. It defines an
+ * interface for the algorithms to implement, and is used by the IPAs to
+ * interact with the concrete implementation.
+ */
+
+/**
+ * \fn AwbAlgorithm::init
+ * \brief Initialize the algorithm with the given tuning data
+ * \param[in] tuningData The tuning data to use for the algorithm
+ *
+ * \return 0 on success, a negative error code otherwise
+ */
+
+/**
+ * \fn AwbAlgorithm::calculateAwb
+ * \brief Calculate awb data from the given statistics
+ * \param[in] stats The statistics to use for the calculation
+ * \param[in] lux The lux value of the scene
+ *
+ * Calculate an AwbResult object from the given statistics and lux value. A \a
+ * lux value of 0 means it is unknown or invalid and the algorithm shall ignore
+ * it.
+ *
+ * \return The awb result
+ */
+
+/**
+ * \fn AwbAlgorithm::gainsFromColourTemperature
+ * \brief Compute white balance gains from a colour temperature
+ * \param[in] colourTemperature The colour temperature in Kelvin
+ *
+ * Compute the white balance gains from a \a colourTemperature. This function
+ * does not take any statistics into account. It is used to compute the colour
+ * gains when the user manually specifies a colour temperature.
+ *
+ * \return The colour gains
+ */
+
+/**
+ * \fn AwbAlgorithm::controls
+ * \brief Get the controls info map for this algorithm
+ *
+ * \return The controls info map
+ */
+
+/**
+ * \fn AwbAlgorithm::handleControls
+ * \param[in] controls The controls to handle
+ * \brief Handle the controls supplied in a request
+ */
+
+/**
+ * \var AwbAlgorithm::controls_
+ * \brief Controls info map for the controls provided by the algorithm
+ */
+
+} /* namespace ipa */
+
+} /* namespace libcamera */
diff --git a/src/ipa/libipa/awb.h b/src/ipa/libipa/awb.h
new file mode 100644
index 00000000..95be01b0
--- /dev/null
+++ b/src/ipa/libipa/awb.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024 Ideas on Board Oy
+ *
+ * Generic AWB algorithms
+ */
+
+#pragma once
+
+#include <libcamera/controls.h>
+#include "libcamera/internal/vector.h"
+#include "libcamera/internal/yaml_parser.h"
+
+namespace libcamera {
+
+namespace ipa {
+
+struct AwbResult {
+	RGB<double> gains;
+	double colourTemperature;
+};
+
+struct AwbStats {
+	virtual double computeColourError(const RGB<double> &gains) const = 0;
+	virtual RGB<double> getRGBMeans() const = 0;
+};
+
+class AwbAlgorithm
+{
+public:
+	virtual ~AwbAlgorithm() = default;
+
+	virtual int init(const YamlObject &tuningData) = 0;
+	virtual AwbResult calculateAwb(const AwbStats &stats, int lux) = 0;
+	virtual RGB<double> gainsFromColourTemperature(double colourTemperature) = 0;
+
+	const ControlInfoMap::Map &controls() const
+	{
+		return controls_;
+	}
+
+	virtual void handleControls([[maybe_unused]] const ControlList &controls) {}
+
+protected:
+	ControlInfoMap::Map controls_;
+};
+
+} /* namespace ipa */
+
+} /* namespace libcamera */
diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
index 12d8d15b..5be51d2c 100644
--- a/src/ipa/libipa/meson.build
+++ b/src/ipa/libipa/meson.build
@@ -3,6 +3,7 @@
 libipa_headers = files([
     'agc_mean_luminance.h',
     'algorithm.h',
+    'awb.h',
     'camera_sensor_helper.h',
     'colours.h',
     'exposure_mode_helper.h',
@@ -19,6 +20,7 @@ libipa_headers = files([
 libipa_sources = files([
     'agc_mean_luminance.cpp',
     'algorithm.cpp',
+    'awb.cpp',
     'camera_sensor_helper.cpp',
     'colours.cpp',
     'exposure_mode_helper.cpp',