OSG动画学习

OSG动画学习

转自：http://bbs.osgchina.org/forum.php?mod=viewthread&tid=3899&_dsign=2587a6a9

学习动画,看了osganimationskinning这个例子,感觉OSG的动画实现的太灵活了.
一个简单的模型节点变换动画过程如下:

1.定义一些变换位置
2.定义动画关键帧,包含了时间,位置,旋转等数据
这里可以设置受变化作用的节点
3.给节点设置一个动画管理器,这个动画管理器是继承自Osg::NodeCallback,所以其实是个Callback类.
4.把定义的关键帧的数据,送给动画管理器
5.创建一个等待变化的节点
6.把变化节点的顶点数据与给出的变换位置进行映射,此时定义的是这些节点中每个顶点的变化方式
7.开始动画

好的东西写不出来,只把这个程序的一些理解记录一下.
这个例子来自OSG的代码中的Example->osganimationskinning

 /*  -*-c++-*-
 *  Copyright (C) 2008 Cedric Pinson <mornifle@plopbyte.net>
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * OpenSceneGraph Public License for more details.
 */
 #include <iostream>
 #include <osg/Geometry>
 #include <osg/MatrixTransform>
 #include <osg/Geode>
 #include <osgViewer/Viewer>
 #include <osgGA/TrackballManipulator>
 #include <osgUtil/SmoothingVisitor>
 #include <osg/io_utils>
 #include <osgAnimation/Bone>
 #include <osgAnimation/Skeleton>
 #include <osgAnimation/RigGeometry>
 #include <osgAnimation/Skinning>
 #include <osgAnimation/BasicAnimationManager>

 // 创建的是些辅助的线条,跟随节点的运动
 osg::Geode* createAxis()
 {
     osg::Geode* geode (new osg::Geode());
     osg::Geometry* geometry (new osg::Geometry());
     osg::Vec3Array* vertices (new osg::Vec3Array());
     vertices->push_back (osg::Vec3 ( 0.0, 0.0, 0.0));
     vertices->push_back (osg::Vec3 ( 1.0, 0.0, 0.0));
     vertices->push_back (osg::Vec3 ( 0.0, 0.0, 0.0));
     vertices->push_back (osg::Vec3 ( 0.0, 1.0, 0.0));
     vertices->push_back (osg::Vec3 ( 0.0, 0.0, 0.0));
     vertices->push_back (osg::Vec3 ( 0.0, 0.0, 1.0));
     geometry->setVertexArray (vertices);
     osg::Vec4Array* colors (new osg::Vec4Array());
     colors->push_back (osg::Vec4 (1.0f, 0.0f, 0.0f, 1.0f));
     colors->push_back (osg::Vec4 (1.0f, 0.0f, 0.0f, 1.0f));
     colors->push_back (osg::Vec4 (0.0f, 1.0f, 0.0f, 1.0f));
     colors->push_back (osg::Vec4 (0.0f, 1.0f, 0.0f, 1.0f));
     colors->push_back (osg::Vec4 (0.0f, 0.0f, 1.0f, 1.0f));
     colors->push_back (osg::Vec4 (0.0f, 0.0f, 1.0f, 1.0f));
     geometry->setColorArray (colors);
     geometry->setColorBinding (osg::Geometry::BIND_PER_VERTEX);
     geometry->addPrimitiveSet(new osg:rawArrays(osg:rimitiveSet:INES,,));
     geode->addDrawable( geometry );
     return geode;
 }
 // 创建了一个等待变换的BOX
 osgAnimation::RigGeometry* createTesselatedBox(int nsplit, float size)
 {
     osgAnimation::RigGeometry* geometry = new osgAnimation::RigGeometry;
     osg::ref_ptr<osg::Vec3Array> vertices (new osg::Vec3Array());
     osg::ref_ptr<osg::Vec3Array> colors (new osg::Vec3Array());
     geometry->setVertexArray (vertices.get());
     geometry->setColorArray (colors.get());
     geometry->setColorBinding (osg::Geometry::BIND_PER_VERTEX);    

     float step = size / nsplit;
     float s = 0.5/4.0;
     for (int i = ; i < nsplit; i++)
     {
         float x = - + i * step;
         std::cout << x << std::endl;
         vertices->push_back (osg::Vec3 ( x, s, s));
         vertices->push_back (osg::Vec3 ( x, -s, s));
         vertices->push_back (osg::Vec3 ( x, -s, -s));
         vertices->push_back (osg::Vec3 ( x, s, -s));
         osg::Vec3 c (,,);
         c[i%] = ;
         colors->push_back (c);
         colors->push_back (c);
         colors->push_back (c);
         colors->push_back (c);
     }
     osg::ref_ptr<osg::UIntArray> array = new osg::UIntArray;
     for (int i = ; i < nsplit - ; i++)
     {
         int base = i * ;
         array->push_back(base);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
         array->push_back(base+);
     }

     geometry->addPrimitiveSet(new osg:rawElementsUInt(osg:rimitiveSet::TRIANGLES, array->size(), &array->front()));
     geometry->setUseDisplayList( false );
     return geometry;
 }
 // 把变化节点的顶点数据与给出的变换位置进行映射,此时定义的是这些节点中每个顶点的变化方式
 void initVertexMap(osgAnimation::Bone* b0,
                    osgAnimation::Bone* b1,
                    osgAnimation::Bone* b2,
                    osgAnimation::RigGeometry* geom,
                    osg::Vec3Array* array)
 {
     osgAnimation::VertexInfluenceSet vertexesInfluences;
     osgAnimation::VertexInfluenceMap* vim = new osgAnimation::VertexInfluenceMap;
     (*vim)[b0->getName()].setName(b0->getName());
     (*vim)[b1->getName()].setName(b1->getName());
     (*vim)[b2->getName()].setName(b2->getName());
     for (int i = ; i < (int)array->size(); i++)
     {
         float val = (*array)[];
         std::cout << val << std::endl;
         // 把每个顶点的变换分配给变换节点
         if (val >= - && val <= )
             (*vim)[b0->getName()].push_back(osgAnimation::VertexIndexWeight(i,));
         else if ( val >  && val <= )
             (*vim)[b1->getName()].push_back(osgAnimation::VertexIndexWeight(i,));
         else if ( val > )
             (*vim)[b2->getName()].push_back(osgAnimation::VertexIndexWeight(i,));
     }
     geom->setInfluenceMap(vim);
 }

 int main (int argc, char* argv[])
 {
     osg::ArgumentParser arguments(&argc, argv);
     osgViewer::Viewer viewer(arguments);
     viewer.setCameraManipulator(new osgGA::TrackballManipulator());
     osg::ref_ptr<osgAnimation::Skeleton> skelroot = new osgAnimation::Skeleton;
     skelroot->setDefaultUpdateCallback();
     // 定义一些变换位置,这些位置会在关键帧的设置用到
     osg::ref_ptr<osgAnimation::Bone> root = new osgAnimation::Bone;
     {
         root->setBindMatrixInBoneSpace(osg::Matrix::identity());
         root->setBindMatrixInBoneSpace(osg::Matrix::translate(-,,));
         root->setName("root");
         root->setDefaultUpdateCallback();
     }
     osg::ref_ptr<osgAnimation::Bone> right0 = new osgAnimation::Bone;
     right0->setBindMatrixInBoneSpace(osg::Matrix::translate(,,));
     right0->setName("right0");
     right0->setDefaultUpdateCallback("right0");
     osg::ref_ptr<osgAnimation::Bone> right1 = new osgAnimation::Bone;
     right1->setBindMatrixInBoneSpace(osg::Matrix::translate(,,));
     right1->setName("right1");
     right1->setDefaultUpdateCallback("right1");
     // 定义变换点之间的父子关系,也就是相对变换的关系
     root->addChild(right0.get());
     right0->addChild(right1.get());
     skelroot->addChild(root.get());
     osg::Group* scene = new osg::Group;
     osg::ref_ptr<osgAnimation::BasicAnimationManager> manager = new osgAnimation::BasicAnimationManager;
     scene->setUpdateCallback(manager.get());
 // 关键帧的定义,时间和位置,现在给的是旋转运动方式,更多的变换方式,可以看一下osgAnimation中的数据结构定义
     // 定义right0的关键帧,时间和旋转
     osgAnimation::Animation* anim = new osgAnimation::Animation;
     {
         osgAnimation:uatKeyframeContainer* keys0 = new osgAnimation:uatKeyframeContainer;
         osg:uat rotate;
         rotate.makeRotate(osg:I_2, osg::Vec3(,,));
         // osgAnimation:uatKeyframe(0,osg:uat(0,0,0,1))中第一个参数是时间点,单位是秒,第二个参数就是这个时间点,要旋转到的位置,本例中是旋转,也可以换成其它变换方式
         keys0->push_back(osgAnimation:uatKeyframe(,osg:uat(,,,)));
         keys0->push_back(osgAnimation:uatKeyframe(,rotate));
         keys0->push_back(osgAnimation:uatKeyframe(,rotate));
         osgAnimation:uatSphericalLinearSampler* sampler = new osgAnimation:uatSphericalLinearSampler;
         sampler->setKeyframeContainer(keys0);
         // osgAnimation::AnimationUpdateCallback* cb = dynamic_cast<osgAnimation::AnimationUpdateCallback*>(right0->getUpdateCallback());
         osgAnimation:uatSphericalLinearChannel* channel = new osgAnimation:uatSphericalLinearChannel(sampler);
         channel->setName("quaternion");
         channel->setTargetName("right0");
         anim->addChannel(channel);
     }
     // 定义right1的关键帧
     {
         osgAnimation:uatKeyframeContainer* keys1 = new osgAnimation:uatKeyframeContainer;
         osg:uat rotate;
         rotate.makeRotate(osg:I_2, osg::Vec3(,,));
         keys1->push_back(osgAnimation:uatKeyframe(,osg:uat(,,,)));
         keys1->push_back(osgAnimation:uatKeyframe(,osg:uat(,,,)));
         keys1->push_back(osgAnimation:uatKeyframe(,rotate));
         osgAnimation:uatSphericalLinearSampler* sampler = new osgAnimation:uatSphericalLinearSampler;
         sampler->setKeyframeContainer(keys1);
         osgAnimation:uatSphericalLinearChannel* channel = new osgAnimation:uatSphericalLinearChannel(sampler);
         //osgAnimation::AnimationUpdateCallback* cb = dynamic_cast<osgAnimation::AnimationUpdateCallback*>(right1->getUpdateCallback());
         channel->setName("quaternion");
         channel->setTargetName("right1");
         anim->addChannel(channel);
     }

     // 把时间和位置告诉动画管理器
     manager->registerAnimation(anim);
     manager->buildTargetReference();

     // let's start !   开始动画
     manager->playAnimation(anim);
     // we will use local data from the skeleton
     osg::MatrixTransform* rootTransform = new osg::MatrixTransform;
     rootTransform->setMatrix(osg::Matrix::rotate(osg:I_2,osg::Vec3(,,)));
     // 把创建的线条指示放到变换节点中,主要是一个指示作用
     right0->addChild(createAxis());
     // 使节点数据更新完毕后,再进行渲染动作
     right0->setDataVariance(osg::Object:YNAMIC);
     right1->addChild(createAxis());
     right1->setDataVariance(osg::Object:YNAMIC);
     //
     osg::MatrixTransform* trueroot = new osg::MatrixTransform;
     trueroot->setMatrix(osg::Matrix(root->getMatrixInBoneSpace().ptr()));
     trueroot->addChild(createAxis());
     trueroot->addChild(skelroot.get());
     trueroot->setDataVariance(osg::Object:YNAMIC);
     // trueroot也是节点,需要加到场景中去,现在是把它设置为rootTransform的一个子节点
     rootTransform->addChild(trueroot);
     scene->addChild(rootTransform);

     // 现在创建等待变换的盒子
     osgAnimation::RigGeometry* geom = createTesselatedBox(, 4.0);
     osg::Geode* geode = new osg::Geode;
     geode->addDrawable(geom);
     skelroot->addChild(geode);
     osg::ref_ptr<osg::Vec3Array> src = dynamic_cast<osg::Vec3Array*>(geom->getVertexArray());
     geom->getOrCreateStateSet()->setMode(GL_LIGHTING, false);
     geom->setDataVariance(osg::Object:YNAMIC);
     // 给盒子的每个顶点设置变换方式
     initVertexMap(root.get(), right0.get(), right1.get(), geom, src.get());
     // let's run !
     viewer.setSceneData( scene );
     viewer.realize();
     // 开始运行了
     while (!viewer.done())
     {
         viewer.frame();
     }
     return ;
 }