magnum/src/SceneGraph/Animable.h

#ifndef Magnum_SceneGraph_Animable_h
#define Magnum_SceneGraph_Animable_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013 Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/** @file
 * @brief Class Magnum::SceneGraph::BasicAnimable, typedef Magnum::SceneGraph::Animable2D, Magnum::SceneGraph::Animable3D, enum Magnum::SceneGraph::AnimationState
 */

#include "AbstractGroupedFeature.h"

#include "magnumSceneGraphVisibility.h"

namespace Magnum { namespace SceneGraph {

/**
@brief Animation state

@see BasicAnimable::setState()
*/
enum class AnimationState: UnsignedByte {
    /**
     * The animation is stopped. The animation will be started from the
     * beginning when state is changed to @ref AnimationState "AnimationState::Running".
     */
    Stopped,

    /**
     * The animation is stopped. The animation will continue from paused
     * position when state is changed to @ref AnimationState "AnimationState::Running".
     */
    Paused,

    /** The animation is running. */
    Running
};

/** @debugoperator{Magnum::SceneGraph::BasicAnimable} */
Debug MAGNUM_SCENEGRAPH_EXPORT operator<<(Debug debug, AnimationState value);

/**
@brief %Animable

Adds animation feature to object. Each %Animable is part of some AnimableGroup,
which takes care of running the animations.

@section Animable-usage Usage

First thing is add Animable feature to some object and implement
animationStep(). You can do it conveniently using multiple inheritance (see
@ref scenegraph-features for introduction). Override animationStep() to
implement your animation, the function provides both absolute animation
time and time delta. Example:
@code
typedef SceneGraph::Object<SceneGraph::MatrixTransformation3D<>> Object3D;
typedef SceneGraph::Scene<SceneGraph::MatrixTransformation3D<>> Scene3D;

class AnimableObject: public Object3D, SceneGraph::Animable3D {
    public:
        AnimableObject(Object* parent = nullptr, SceneGraph::DrawableGroup3D<>* group = nullptr): Object3D(parent), SceneGraph::Animable3D(this, group) {
            setDuration(10.0f);
            // ...
        }

        void animationStep(Float time, Float delta) override {
            rotateX(15.0_degf*delta); // rotate at 15 degrees per second
        }
}
@endcode

Then add the object to your scene and some animation group. You can also use
BasicAnimableGroup::add() and BasicAnimableGroup::remove() instead of passing
the group in the constructor. The animation is initially in stopped state and
without repeat, see setState(), setRepeated() and setRepeatCount() for more
information.
@code
Scene3D scene;
SceneGraph::AnimableGroup3D animables;

(new AnimableObject(&scene, &animables))
    ->setState(SceneGraph::AnimationState::Running);
// ...
@endcode

Animation step is performed by calling BasicAnimableGroup::step() in your draw
event implementation. The function expects absolute time from relative to some
fixed point in the past and time delta (i.e. duration of the frame). You can
use Timeline for that, see its documentation for more information.
@code
Timeline timeline;
timeline.start();

void MyApplication::drawEvent() {
    animables.step(timeline.lastFrameTime(), timeline.lastFrameDuration());

    // ...

    timeline.nextFrame();
}
@endcode

@section Animable-performance Using animable groups to improve performance

Animable group is optimized for case when no animation is running - it just
puts itself to rest and waits until some animation changes its state to
@ref AnimationState "AnimationState::Running" again. If you put animations
which are not pernamently running to separate group, they will not be always
traversed when calling BasicAnimableGroup::step(), saving precious frame time.

@section Animable-explicit-specializations Explicit template specializations

The following specialization are explicitly compiled into %SceneGraph library.
For other specializations (e.g. using Double type) you have to use
Animable.hpp implementation file to avoid linker errors. See also
@ref compilation-speedup-hpp for more information.

 - @ref BasicAnimable "BasicAnimable<2, Float>", @ref BasicAnimableGroup "BasicAnimableGroup<2, Float>"
 - @ref BasicAnimable "BasicAnimable<3, Float>", @ref BasicAnimableGroup "BasicAnimableGroup<3, Float>"

@see @ref Animable2D, @ref Animable3D, @ref scenegraph, @ref AnimableGroup2D,
    @ref AnimableGroup3D
*/
template<UnsignedInt dimensions, class T> class MAGNUM_SCENEGRAPH_EXPORT BasicAnimable: public AbstractBasicGroupedFeature<dimensions, BasicAnimable<dimensions, T>, T> {
    friend class BasicAnimableGroup<dimensions, T>;

    public:
        /**
         * @brief Constructor
         * @param object    %Object this animable belongs to
         * @param group     Group this animable belongs to
         *
         * Creates stopped non-repeating animation with infinite duration,
         * adds the feature to the object and also to group, if specified.
         * @see setDuration(), setState(), setRepeated(), BasicAnimableGroup::add()
         */
        explicit BasicAnimable(AbstractBasicObject<dimensions, T>* object, BasicAnimableGroup<dimensions, T>* group = nullptr);

        ~BasicAnimable();

        /** @brief Animation duration */
        Float duration() const { return _duration; }

        /** @brief Animation state */
        AnimationState state() const { return currentState; }

        /**
         * @brief Set animation state
         * @return Pointer to self (for method chaining)
         *
         * Note that changing state from @ref AnimationState "AnimationState::Stopped"
         * to @ref AnimationState "AnimationState::Paused" is ignored and
         * animation remains in @ref AnimationState "AnimationState::Stopped"
         * state. See also animationStep() for more information.
         * @see animationStarted(), animationPaused(), animationResumed(),
         *      animationStopped()
         */
        BasicAnimable<dimensions, T>* setState(AnimationState state);

        /**
         * @brief Whether the animation is repeated
         *
         * @see repeatCount()
         */
        bool isRepeated() const { return _repeated; }

        /**
         * @brief Enable/disable repeated animation
         * @return Pointer to self (for method chaining)
         *
         * Default is `false`.
         * @see setRepeatCount()
         */
        BasicAnimable<dimensions, T>* setRepeated(bool repeated) {
            _repeated = repeated;
            return this;
        }

        /**
         * @brief Repeat count
         *
         * @see isRepeated()
         */
        UnsignedShort repeatCount() const { return _repeatCount; }

        /**
         * @brief Set repeat count
         * @return Pointer to self (for method chaining)
         *
         * Has effect only if repeated animation is enabled. `0` means
         * infinitely repeated animation. Default is `0`.
         * @see setRepeated()
         */
        BasicAnimable<dimensions, T>* setRepeatCount(UnsignedShort count) {
            _repeatCount = count;
            return this;
        }

        /**
         * @brief %Animable group containing this animable
         *
         * If the animable doesn't belong to any group, returns `nullptr`.
         */
        BasicAnimableGroup<dimensions, T>* group();
        const BasicAnimableGroup<dimensions, T>* group() const; /**< @overload */

    protected:
        /**
         * @brief Set animation duration
         * @return Pointer to self (for method chaining)
         *
         * Sets duration of the animation cycle in seconds. Set to `0.0f` for
         * infinite non-repeating animation. Default is `0.0f`.
         */
        /* Protected so only animation implementer can change it */
        BasicAnimable<dimensions, T>* setDuration(Float duration) {
            _duration = duration;
            return this;
        }

        /**
         * @brief Perform animation step
         * @param time      Time from start of the animation
         * @param delta     Time delta for current frame
         *
         * This function is periodically called from BasicAnimableGroup::step()
         * if the animation state is set to @ref AnimationState "AnimationState::Running".
         * After animation duration is exceeded and repeat is not enabled or
         * repeat count is exceeded, the animation state is set to
         * @ref AnimationState "AnimationState::Stopped".
         *
         * If the animation is resumed from @ref AnimationState "AnimationState::Paused",
         * this function is called with @p time continuing from the point
         * when it was paused. If the animation is resumed from
         * @ref AnimationState "AnimationState::Stopped", @p time starts with
         * zero.
         *
         * @see state(), duration(), isRepeated(), repeatCount()
         */
        virtual void animationStep(Float time, Float delta) = 0;

        /**
         * @brief Action on animation start
         *
         * Called from BasicAnimableGroup::step() when state is changed from
         * @ref AnimationState "AnimationState::Stopped" to
         * @ref AnimationState "AnimationState::Running" and before first
         * animationStep() is called.
         *
         * Default implementation does nothing.
         *
         * @see setState()
         */
        virtual void animationStarted() {}

        /**
         * @brief Action on animation pause
         *
         * Called from BasicAnimableGroup::step() when state changes from
         * @ref AnimationState "AnimationState::Running" to
         * @ref AnimationState "AnimationState::Paused" and after last
         * animationStep() is called.
         *
         * Default implementation does nothing.
         *
         * @see setState()
         */
        virtual void animationPaused() {}

        /**
         * @brief Action on animation resume
         *
         * Called from BasicAnimableGroup::step() when state changes from
         * @ref AnimationState "AnimationState::Paused" to
         * @ref AnimationState "AnimationState::Running" and before first
         * animationStep() is called.
         *
         * Default implementation does nothing.
         *
         * @see setState()
         */
        virtual void animationResumed() {}

        /**
         * @brief Action on animation stop
         *
         * Called from BasicAnimableGroup::step() when state changes from either
         * @ref AnimationState "AnimationState::Running" or
         * @ref AnimationState "AnimationState::Paused" to
         * @ref AnimationState "AnimationState::Stopped" and after last
         * animationStep() is called.
         *
         * You may want to use this function to properly finish the animation
         * in case the framerate is not high enough to have animationStep()
         * called enough times. Default implementation does nothing.
         *
         * @see setState()
         */
        virtual void animationStopped() {}

    private:
        Float _duration;
        Float startTime, pauseTime;
        AnimationState previousState;
        AnimationState currentState;
        bool _repeated;
        UnsignedShort _repeatCount;
        UnsignedShort repeats;
};

/**
@brief Animable for two-dimensional float scenes

@see @ref Animable3D
*/
typedef BasicAnimable<2, Float> Animable2D;

/**
@brief Animable for three-dimensional float scenes

@see @ref Animable2D
*/
typedef BasicAnimable<3, Float> Animable3D;

}}

#endif