[libcamera-devel] [PATCH v6 03/10] ipa: Add base class defining AF algorithm interface

[Daniel Semkowicz]

Hi Laurent,

On Wed, Apr 26, 2023 at 3:24 AM Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Daniel,
>
> Thank you for the patch.
>
> On Fri, Mar 31, 2023 at 10:19:23AM +0200, Daniel Semkowicz via libcamera-devel wrote:
> > Define common interface with pure virtual methods that should be
> > implemented by the Auto Focus algorithm implementations.
> > Interface methods match the AF controls that can be set in the frame
> > request. Common implementation of controls parsing is provided,
> > so the AF algorithms deriving from this interface should be able
> > to reuse it.
>
> I'm a bit concerned here, as creating abstract classes with a single
> user always worries me that we don't have enough data points to create a
> correct abstraction. Your series includes a single AF implementation, do
> you already envision different implementations that could use the same
> interface ? I'm sorry if this point has been raised during the review of
> previous versions, I haven't followed them very closely so far.

This interface basically maps the AF controls on the separate interface
functions and provides queueRequest() function to translate requested controls
to function calls. This makes the interface closely tied with the AF controls.
In the end each AF algorithm needs to handle the AF controls, so it forces
algorithm architecture to be structured in the way, the controls are structured.
I do not envision another implementation yet, but you can already look on the
Raspberry Pi implementation of the PDAF. This is a different implementation,
but the RPiController::AfAlgorithm is structured almost the same way.

Best regards
Daniel

>
> > Signed-off-by: Daniel Semkowicz <dse at thaumatec.com>
> > ---
> >  src/ipa/libipa/algorithms/af.cpp      | 159 ++++++++++++++++++++++++++
> >  src/ipa/libipa/algorithms/af.h        |  46 ++++++++
> >  src/ipa/libipa/algorithms/meson.build |   9 ++
> >  src/ipa/libipa/meson.build            |   6 +
> >  4 files changed, 220 insertions(+)
> >  create mode 100644 src/ipa/libipa/algorithms/af.cpp
> >  create mode 100644 src/ipa/libipa/algorithms/af.h
> >  create mode 100644 src/ipa/libipa/algorithms/meson.build
> >
> > diff --git a/src/ipa/libipa/algorithms/af.cpp b/src/ipa/libipa/algorithms/af.cpp
> > new file mode 100644
> > index 00000000..0808aa3f
> > --- /dev/null
> > +++ b/src/ipa/libipa/algorithms/af.cpp
> > @@ -0,0 +1,159 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2023, Theobroma Systems
> > + *
> > + * af.cpp - Autofocus control algorithm interface
> > + */
> > +
> > +#include "af.h"
> > +
> > +/**
> > + * \file af.h
> > + * \brief AF algorithm common interface
> > + */
> > +
> > +namespace libcamera {
> > +
> > +namespace ipa::algorithms {
> > +
> > +/**
> > + * \class Af
> > + * \brief Common interface for auto-focus algorithms
> > + *
> > + * The Af class defines a standard interface for IPA auto focus algorithms.
> > + */
> > +
> > +/**
> > + * \brief Provide control values to the algorithm
> > + * \param[in] controls The list of user controls
> > + *
> > + * This method should be called in the libcamera::ipa::Algorithm::queueRequest()
> > + * method of the platform layer.
> > + */
> > +void Af::queueRequest(const ControlList &controls)
> > +{
> > +     using namespace controls;
> > +
> > +     for (auto const &[id, value] : controls) {
> > +             switch (id) {
> > +             case AF_MODE: {
> > +                     setMode(static_cast<AfModeEnum>(value.get<int32_t>()));
> > +                     break;
> > +             }
> > +             case AF_RANGE: {
> > +                     setRange(static_cast<AfRangeEnum>(value.get<int32_t>()));
> > +                     break;
> > +             }
> > +             case AF_SPEED: {
> > +                     setSpeed(static_cast<AfSpeedEnum>(value.get<int32_t>()));
> > +                     break;
> > +             }
> > +             case AF_METERING: {
> > +                     setMeteringMode(static_cast<AfMeteringEnum>(value.get<int32_t>()));
> > +                     break;
> > +             }
> > +             case AF_WINDOWS: {
> > +                     setWindows(value.get<Span<const Rectangle>>());
> > +                     break;
> > +             }
> > +             case AF_TRIGGER: {
> > +                     setTrigger(static_cast<AfTriggerEnum>(value.get<int32_t>()));
> > +                     break;
> > +             }
> > +             case AF_PAUSE: {
> > +                     setPause(static_cast<AfPauseEnum>(value.get<int32_t>()));
> > +                     break;
> > +             }
> > +             case LENS_POSITION: {
> > +                     setLensPosition(value.get<float>());
> > +                     break;
> > +             }
> > +             default:
> > +                     break;
> > +             }
> > +     }
> > +}
> > +
> > +/**
> > + * \fn Af::setMode()
> > + * \brief Set auto focus mode
> > + * \param[in] mode AF mode
> > + *
> > + * \sa libcamera::controls::AfMode
> > + */
> > +
> > +/**
> > + * \fn Af::setRange()
> > + * \brief Set the range of focus distances that is scanned
> > + * \param[in] range AF range
> > + *
> > + * \sa libcamera::controls::AfRange
> > + */
> > +
> > +/**
> > + * \fn Af::setSpeed()
> > + * \brief Set how fast algorithm should move the lens
> > + * \param[in] speed Lens move speed
> > + *
> > +* \sa libcamera::controls::AfSpeed
> > + */
> > +
> > +/**
> > + * \fn Af::setMeteringMode()
> > + * \brief Set AF metering mode
> > + * \param[in] metering AF metering mode
> > + *
> > + * \sa libcamera::controls::AfMetering
> > + */
> > +
> > +/**
> > + * \fn Af::setWindows()
> > + * \brief Set AF windows
> > + * \param[in] windows AF windows
> > + *
> > + * \sa libcamera::controls::AfWindows
> > + */
> > +
> > +/**
> > + * \fn Af::setTrigger()
> > + * \brief Starts or cancels the autofocus scan
> > + * \param[in] trigger Trigger mode
> > + *
> > + * \sa libcamera::controls::AfTrigger
> > + */
> > +
> > +/**
> > + * \fn Af::setPause()
> > + * \brief Pause the autofocus while in AfModeContinuous mode
> > + * \param[in] pause Pause mode
> > + *
> > + * \sa libcamera::controls::AfPause
> > + */
> > +
> > +/**
> > + * \fn Af::setLensPosition()
> > + * \brief Set the lens position while in AfModeManual
> > + * \param[in] lensPosition Lens position
> > + *
> > + * \sa libcamera::controls::LensPosition
> > + */
> > +
> > +/**
> > + * \fn Af::state()
> > + * \brief Get the current state of the AF algorithm
> > + * \return AF state
> > + *
> > + * \sa libcamera::controls::AfState
> > + */
> > +
> > +/**
> > + * \fn Af::pauseState()
> > + * \brief Get the current pause state of the AF algorithm
> > + * \return AF pause state
> > + *
> > + * \sa libcamera::controls::AfPauseState
> > + */
> > +
> > +} /* namespace ipa::algorithms */
> > +
> > +} /* namespace libcamera */
> > diff --git a/src/ipa/libipa/algorithms/af.h b/src/ipa/libipa/algorithms/af.h
> > new file mode 100644
> > index 00000000..47c919fe
> > --- /dev/null
> > +++ b/src/ipa/libipa/algorithms/af.h
> > @@ -0,0 +1,46 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2023, Theobroma Systems
> > + *
> > + * af.h - Autofocus control algorithm interface
> > + */
> > +
> > +#pragma once
> > +
> > +#include <libcamera/control_ids.h>
>
> You should also include geometry.h and span.h as you're using the
> Rectangle and Span classes below.
>
> > +
> > +namespace libcamera {
> > +
> > +namespace ipa::algorithms {
> > +
> > +class Af
> > +{
> > +public:
> > +     virtual ~Af() = default;
> > +
> > +     void queueRequest(const ControlList &controls);
> > +
> > +     virtual void setMode(controls::AfModeEnum mode) = 0;
> > +
> > +     virtual void setRange(controls::AfRangeEnum range) = 0;
> > +
> > +     virtual void setSpeed(controls::AfSpeedEnum speed) = 0;
> > +
> > +     virtual void setMeteringMode(controls::AfMeteringEnum metering) = 0;
> > +
> > +     virtual void setWindows(Span<const Rectangle> windows) = 0;
> > +
> > +     virtual void setTrigger(controls::AfTriggerEnum trigger) = 0;
> > +
> > +     virtual void setPause(controls::AfPauseEnum pause) = 0;
> > +
> > +     virtual void setLensPosition(float lensPosition) = 0;
> > +
> > +     virtual controls::AfStateEnum state() = 0;
> > +
> > +     virtual controls::AfPauseStateEnum pauseState() = 0;
> > +};
> > +
> > +} /* namespace ipa::algorithms */
> > +
> > +} /* namespace libcamera */
> > diff --git a/src/ipa/libipa/algorithms/meson.build b/src/ipa/libipa/algorithms/meson.build
> > new file mode 100644
> > index 00000000..3df4798f
> > --- /dev/null
> > +++ b/src/ipa/libipa/algorithms/meson.build
> > @@ -0,0 +1,9 @@
> > +# SPDX-License-Identifier: CC0-1.0
> > +
> > +libipa_algorithms_headers = files([
> > +    'af.h',
> > +])
> > +
> > +libipa_algorithms_sources = files([
> > +    'af.cpp',
> > +])
> > diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
> > index 016b8e0e..134c2dba 100644
> > --- a/src/ipa/libipa/meson.build
> > +++ b/src/ipa/libipa/meson.build
> > @@ -1,5 +1,7 @@
> >  # SPDX-License-Identifier: CC0-1.0
> >
> > +subdir('algorithms')
> > +
> >  libipa_headers = files([
> >      'algorithm.h',
> >      'camera_sensor_helper.h',
> > @@ -8,6 +10,8 @@ libipa_headers = files([
> >      'module.h',
> >  ])
> >
> > +libipa_headers += libipa_algorithms_headers
> > +
> >  libipa_sources = files([
> >      'algorithm.cpp',
> >      'camera_sensor_helper.cpp',
> > @@ -16,6 +20,8 @@ libipa_sources = files([
> >      'module.cpp',
> >  ])
> >
> > +libipa_sources += libipa_algorithms_sources
> > +
> >  libipa_includes = include_directories('..')
> >
> >  libipa = static_library('ipa', [libipa_sources, libipa_headers],
>
> --
> Regards,
>
> Laurent Pinchart