camera_sensor_helper.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Google Inc.
 *
 * camera_sensor_helper.h - Helper class that performs sensor-specific parameter computations
 */
 
#pragma once
 
#include <stdint.h>
 
#include <memory>
#include <string>
#include <vector>
 
#include <libcamera/base/class.h>
 
namespace libcamera {
 
namespace ipa {
 
class CameraSensorHelper
{
public:
    CameraSensorHelper() = default;
    virtual ~CameraSensorHelper() = default;
 
    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;
    };
 
    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
    {
        return std::make_unique<_Helper>();
    }
};
 
#define REGISTER_CAMERA_SENSOR_HELPER(name, helper) \
static CameraSensorHelperFactory<helper> global_##helper##Factory(name);
 
} /* namespace ipa */
 
} /* namespace libcamera */