rendering/Transform.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_RENDERING_TRANSFORM_H
#define META_OCEAN_RENDERING_TRANSFORM_H
 
#include "ocean/rendering/Rendering.h"
#include "ocean/rendering/Group.h"
 
#include "ocean/math/HomogenousMatrix4.h"
 
namespace Ocean
{
 
namespace Rendering
{
 
// Forward declaration
class Transform;
 
/**
 * Definition of a smart object reference holding a transform node.
 * @see SmartObjectRef, Transform.
 * @ingroup rendering
 */
typedef SmartObjectRef<Transform> TransformRef;
 
/**
 * Definition of a vector of references holding transform nods
 * @ingroup rendering
 */
typedef std::vector<TransformRef> TransformRefs;
 
/**
 * This class is the base class for all transform nodes.
 * @ingroup rendering
 */
class OCEAN_RENDERING_EXPORT Transform : virtual public Group
{
    public:
 
        /**
         * Definition of a modifier for transform objects.
         * Modifiers can be applies to modify the transformation of one (or several) transformations concurrently based on the identical transformation without changing the scene graph hierarchy.<br>
         * When applied to a transform, the transform's transformation is adjusted as followed:<br>
         * <pre>
         * parent_T_transform = parent_T_transform * transform_T_modifiedTransform
         * </pre>
         */
        class TransformModifier
        {
            friend class Transform;
 
            public:
 
                /**
                 * Returns the transformation of this modifier.
                 * @return The transformation between the modified transform and the original transform (transform_T_modifiedTransform)
                 */
                inline HomogenousMatrix4 transformation() const;
 
                /**
                 * Sets the transformation of this modifier.
                 * @param transform_T_modifiedTransform The transformation between the modified transform and the original transform, must be valid
                 */
                inline void setTransformation(const HomogenousMatrix4& transform_T_modifiedTransform);
 
            protected:
 
                /**
                 * Creates a new modifier with identity transformation.
                 */
                TransformModifier() = default;
 
            protected:
 
                /// The transformation of this modifier.
                HomogenousMatrix4 parent_T_transform_ = HomogenousMatrix4(true);
        };
 
        /**
         * Definition of a shared pointer holding a TransformModifier object.
         * @see TransformModifier.
         */
        typedef std::shared_ptr<TransformModifier> SharedTransformModifier;
 
    public:
 
        /**
         * Returns the transformation of this node relative to the parent node.
         * @return The relative transformation (parent_T_transform)
         */
        virtual HomogenousMatrix4 transformation() const = 0;
 
        /**
         * Returns the TransformModifier object of this transform.
         * @return The transform's modifier, nullptr if no modifier is set
         */
        virtual SharedTransformModifier transformModifier() const = 0;
 
        /**
         * Sets the transformation of this node relative to the parent node.
         * @param parent_T_transform The transformation between this node and the parent node
         */
        virtual void setTransformation(const HomogenousMatrix4& parent_T_transform) = 0;
 
        /**
         * Sets the TransformModifier object for this transformation.
         * @param transformModifier The TransformModifier to be set, nullptr to remove a previously set modifier
         */
        virtual void setTransformModifier(SharedTransformModifier transformModifier) = 0;
 
        /**
         * Returns the type of this object.
         * @see Object::type().
         */
        ObjectType type() const override;
 
        /**
         * Creates a TransformModifier object.
         * @return The new transform modifier object
         */
        static inline SharedTransformModifier createTransformModifier();
 
    protected:
 
        /**
         * Creates a new transform node.
         */
        Transform();
 
        /**
         * Destructs a transform node.
         */
        ~Transform() override;
};
 
inline HomogenousMatrix4 Transform::TransformModifier::transformation() const
{
    ocean_assert(parent_T_transform_.isValid());
 
    return parent_T_transform_;
}
 
inline void Transform::TransformModifier::setTransformation(const HomogenousMatrix4& parent_T_transform)
{
    ocean_assert(parent_T_transform.isValid());
 
    parent_T_transform_ =  parent_T_transform;
}
 
inline Transform::SharedTransformModifier Transform::createTransformModifier()
{
    return SharedTransformModifier(new TransformModifier());
}
 
}
 
}
 
#endif // META_OCEAN_RENDERING_TRANSFORM_H