camera_sensor_helper.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Google Inc.
 *
 * Helper class that performs sensor-specific parameter computations
 */

#pragma once

#include <memory>
#include <optional>
#include <stdint.h>
#include <string>
#include <vector>

#include <libcamera/base/class.h>

namespace libcamera {

namespace ipa {

class CameraSensorHelper
{
public:
    CameraSensorHelper() = default;
    virtual ~CameraSensorHelper() = default;

    std::optional<int16_t> blackLevel() const { return blackLevel_; }
    virtual uint32_t gainCode(double gain) const;
    virtual double gain(uint32_t gainCode) const;

protected:
    enum AnalogueGainType {
        AnalogueGainLinear,
        AnalogueGainExponential,
    };

    struct AnalogueGainLinearConstants {
        int16_t m0;
        int16_t c0;
        int16_t m1;
        int16_t c1;
    };

    struct AnalogueGainExpConstants {
        double a;
        double m;
    };

    union AnalogueGainConstants {
        AnalogueGainLinearConstants linear;
        AnalogueGainExpConstants exp;
    };

    std::optional<int16_t> blackLevel_;
    AnalogueGainType gainType_;
    AnalogueGainConstants gainConstants_;

private:
    LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraSensorHelper)
};

class CameraSensorHelperFactoryBase
{
public:
    CameraSensorHelperFactoryBase(const std::string name);
    virtual ~CameraSensorHelperFactoryBase() = default;

    static std::unique_ptr<CameraSensorHelper> create(const std::string &name);

    static std::vector<CameraSensorHelperFactoryBase *> &factories();

private:
    LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraSensorHelperFactoryBase)

    static void registerType(CameraSensorHelperFactoryBase *factory);

    virtual std::unique_ptr<CameraSensorHelper> createInstance() const = 0;

    std::string name_;
};

template<typename _Helper>
class CameraSensorHelperFactory final : public CameraSensorHelperFactoryBase
{
public:
    CameraSensorHelperFactory(const char *name)
        : CameraSensorHelperFactoryBase(name)
    {
    }

private:
    std::unique_ptr<CameraSensorHelper> createInstance() const override
    {
        return std::make_unique<_Helper>();
    }
};

#define REGISTER_CAMERA_SENSOR_HELPER(name, helper) \
static CameraSensorHelperFactory<helper> global_##helper##Factory(name);

} /* namespace ipa */

} /* namespace libcamera */