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:



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,0,6));
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 = 0; i < nsplit; i++)
{
float x = -1 + 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 (0,0,0);
c[i%3] = 1;
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 = 0; i < nsplit - 1; i++)
{
int base = i * 4;
array->push_back(base);
array->push_back(base+1);
array->push_back(base+4);
array->push_back(base+1);
array->push_back(base+5);
array->push_back(base+4);
array->push_back(base+3);
array->push_back(base);
array->push_back(base+4);
array->push_back(base+7);
array->push_back(base+3);
array->push_back(base+4);
array->push_back(base+5);
array->push_back(base+1);
array->push_back(base+2);
array->push_back(base+2);
array->push_back(base+6);
array->push_back(base+5);
array->push_back(base+2);
array->push_back(base+3);
array->push_back(base+7);
array->push_back(base+6);
array->push_back(base+2);
array->push_back(base+7);
}

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 = 0; i < (int)array->size(); i++)
{
float val = (*array)[0];
std::cout << val << std::endl;
// 把每个顶点的变换分配给变换节点
if (val >= -1 && val <= 0)
(*vim)[b0->getName()].push_back(osgAnimation::VertexIndexWeight(i,1));
else if ( val > 0 && val <= 1)
(*vim)[b1->getName()].push_back(osgAnimation::VertexIndexWeight(i,1));
else if ( val > 1)
(*vim)[b2->getName()].push_back(osgAnimation::VertexIndexWeight(i,1));
}
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(-1,0,0));
root->setName("root");
root->setDefaultUpdateCallback();
}
osg::ref_ptr<osgAnimation::Bone> right0 = new osgAnimation::Bone;
right0->setBindMatrixInBoneSpace(osg::Matrix::translate(1,0,0));
right0->setName("right0");
right0->setDefaultUpdateCallback("right0");
osg::ref_ptr<osgAnimation::Bone> right1 = new osgAnimation::Bone;
right1->setBindMatrixInBoneSpace(osg::Matrix::translate(1,0,0));
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(0,0,1));
// 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(0,osg:uat(0,0,0,1)));
keys0->push_back(osgAnimation:uatKeyframe(3,rotate));
keys0->push_back(osgAnimation:uatKeyframe(6,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(0,0,1));
keys1->push_back(osgAnimation:uatKeyframe(0,osg:uat(0,0,0,1)));
keys1->push_back(osgAnimation:uatKeyframe(3,osg:uat(0,0,0,1)));
keys1->push_back(osgAnimation:uatKeyframe(6,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(1,0,0)));
// 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, 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 0;
}

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