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++ // Copyright (C) 2021 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
++
++ /*!
++
++ \title Morphing Animation
++ \page quick3d-morphing
++
++ \section1 Introduction
++
++ Morphing animation (also known as \e{vertex animation}) is a way to simulate deformations of soft
++ materials. It transforms one shape smoothly into another. This is done by creating a mesh that
++ contains multiple positions for each vertex. Each additional set of positions defines a shape,
++ called a \l{MorphTarget}{morph target}. When animating, a \l{MorphTarget::weight}{weight} is
++ assigned to each target. The effective position of each vertex is calculated by linear interpolation
++ between the positions for that target, according to the weights.
++
++ Morphing differs from \l{Vertex Skinning}{skeletal animation} where we create an imagined skeleton,
++ and rig the model by defining the relationship between each vertex of the model and the nodes of
++ that skeleton.
++
++ Note that the fundamental structure of each morph target must be the same: If three vertices form a
++ triangle in the base model, they will form a triangle in all the morph targets. The triangle can
++ have a completely different position, orientation, and size; or it can even be effectively removed
++ by making it a degenerate triangle with size zero.
++
++ In most cases, the mesh will be created by an external tool, and imported using the \l{Balsam Asset
++ Import Tool}{Balsam} asset import tool. For example, in the Blender 3D editor, morph targets are
++ called "shape keys", and in Autodesk Maya they are called "blend shapes".
++
++ The \l{Qt Quick 3D - Morphing Example}{morphing example} shows how to control the weights of a model
++ imported from Blender.
++
++ The \l{Qt Quick 3D - Custom Morphing Animation}{custom morphing animation example} shows how to
++ create a morph target in C++ by subclassing QQuick3DGeometry.
++ */