af.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Red Hat
 *
 * IPU3 Af algorithm
 */

#pragma once

#include <linux/intel-ipu3.h>

#include <libcamera/base/utils.h>

#include <libcamera/geometry.h>

#include "algorithm.h"

namespace libcamera {

namespace ipa::ipu3::algorithms {

class Af : public Algorithm
{
    /* The format of y_table. From ipu3-ipa repo */
    typedef struct __attribute__((packed)) y_table_item {
        uint16_t y1_avg;
        uint16_t y2_avg;
    } y_table_item_t;
public:
    Af();
    ~Af() = default;

    int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
    void prepare(IPAContext &context, const uint32_t frame,
             IPAFrameContext &frameContext,
             ipu3_uapi_params *params) override;
    void process(IPAContext &context, const uint32_t frame,
             IPAFrameContext &frameContext,
             const ipu3_uapi_stats_3a *stats,
             ControlList &metadata) override;

private:
    void afCoarseScan(IPAContext &context);
    void afFineScan(IPAContext &context);
    bool afScan(IPAContext &context, int min_step);
    void afReset(IPAContext &context);
    bool afNeedIgnoreFrame();
    void afIgnoreFrameReset();
    double afEstimateVariance(Span<const y_table_item_t> y_items, bool isY1);

    bool afIsOutOfFocus(IPAContext &context);

    /* VCM step configuration. It is the current setting of the VCM step. */
    uint32_t focus_;
    /* The best VCM step. It is a local optimum VCM step during scanning. */
    uint32_t bestFocus_;
    /* Current AF statistic variance. */
    double currentVariance_;
    /* The frames are ignore before starting measuring. */
    uint32_t ignoreCounter_;
    /* It is used to determine the derivative during scanning */
    double previousVariance_;
    /* The designated maximum range of focus scanning. */
    uint32_t maxStep_;
    /* If the coarse scan completes, it is set to true. */
    bool coarseCompleted_;
    /* If the fine scan completes, it is set to true. */
    bool fineCompleted_;
};

} /* namespace ipa::ipu3::algorithms */

} /* namespace libcamera */