英文原文: http://test.ogitor.org/tiki/AnimationBlender
動畫混合 -- 實現兩個動畫的切換, 一個動畫逐漸消逝, 另一個動畫逐漸顯示來實現. 主要通過動畫狀態的權重來實現
通過三種方式來實現兩個動畫的混合:
- BlendSwitch - 直接切換至目標動畫
- BlendWhileAnimating - 混合的過程中目標動畫也更新幀, 實現動畫
- BlendThenAnimate - 用源動畫的當前幀混合目標動畫的第一個幀
源碼理解, 主要代碼位于下面兩個函數
AnimationBlender::blend函數 根據傳入的參數設置新轉換的源動畫和目標動畫
AnimationBlender::add函數則更新源動畫和目標動畫(如存在)的狀態和權重
AnimationBlender::blend函數
1. 如果動畫轉換類型為 AnimationBlender::BlendSwitch
直接將源動畫轉換成目標動畫
2. 如果不是這個轉換類型 AnimationBlender::BlendSwitch
如果上次的動畫轉換還未完成
如果新的目標動畫等于上次轉換的源動畫
則反向轉換
如果新的目標動畫不等于上次轉換的源動畫和目標動畫
根據上次轉換的剩余時間設置是顯示上次轉換的源動畫還是目標動畫, 并將其設置為新轉換的源動畫
顯示新轉換的目標動畫, 并設置其權重
假設上次的動畫轉換已經完成了轉換
設置轉換時間, 轉換類型, 目標動畫和其權重
AnimationBlender::addTime 函數
1. 如有動畫在運行
如果存在轉換
更新剩余時間
如剩余時間小于0
禁止源動畫
將目標動畫設置為源動畫, 繼續運行
如剩余時間不小于0
更新源動畫和目標動畫的權重
如轉換類型為AnimationBlender::BlendWhileAnimating
更新目標動畫
判斷動畫是否完成
更新源動畫
完整代碼和Demo代碼
AnimationBlender.h
#ifndef __ANIMATION_BLENDER_H__
#define __ANIMATION_BLENDER_H__
#include <Ogre.h>
using namespace Ogre;
class AnimationBlender
{
public:
enum BlendingTransition
{
BlendSwitch, // stop source and start dest
BlendWhileAnimating, // cross fade, blend source animation out while blending destination animation in
BlendThenAnimate // blend source to first frame of dest, when done, start dest anim
};
private:
Entity *mEntity;
AnimationState *mSource;
AnimationState *mTarget;
BlendingTransition mTransition;
bool loop;
~AnimationBlender() {}
public:
Real mTimeleft, mDuration;
bool complete;
void blend( const String &animation, BlendingTransition transition, Real duration, bool l=true );
void addTime( Real );
Real getProgress() { return mTimeleft/ mDuration; }
AnimationState *getSource() { return mSource; }
AnimationState *getTarget() { return mTarget; }
AnimationBlender( Entity *);
void init( const String &animation, bool l=true );
};
#endif
AnimationBlender.cpp
#include "AnimationBlender.h"
void AnimationBlender::init(const String &animation, bool l)
{
// 初始化, 將所有的動畫禁止, 只允許參數中的動畫運行.
AnimationStateSet *set = mEntity->getAllAnimationStates();
AnimationStateIterator it = set->getAnimationStateIterator();
while(it.hasMoreElements())
{
AnimationState *anim = it.getNext();
anim->setEnabled(false);
anim->setWeight(0);
anim->setTimePosition(0);
}
mSource = mEntity->getAnimationState( animation );
mSource->setEnabled(true);
mSource->setWeight(1);
mTimeleft = 0;
mDuration = 1;
mTarget = 0;
complete = false;
loop = l;
}
void AnimationBlender::blend( const String &animation, BlendingTransition transition, Real duration, bool l )
{
loop = l;
if( transition == AnimationBlender::BlendSwitch )
{
if( mSource != 0 )
mSource->setEnabled(false);
mSource = mEntity->getAnimationState( animation );
mSource->setEnabled(true);
mSource->setWeight(1);
mSource->setTimePosition(0);
mTimeleft = 0;
}
else
{
AnimationState *newTarget = mEntity->getAnimationState( animation );
if( mTimeleft > 0 )
{
// oops, weren't finished yet
if( newTarget == mTarget )
{
// nothing to do! (ignoring duration here)
}
else if( newTarget == mSource )
{
// going back to the source state, so let's switch
mSource = mTarget;
mTarget = newTarget;
mTimeleft = mDuration - mTimeleft; // i'm ignoring the new duration here
}
else
{
// ok, newTarget is really new, so either we simply replace the target with this one, or
// we make the target the new source
if( mTimeleft < mDuration * 0.5 )
{
// simply replace the target with this one
mTarget->setEnabled(false);
mTarget->setWeight(0);
}
else
{
// old target becomes new source
mSource->setEnabled(false);
mSource->setWeight(0);
mSource = mTarget;
}
mTarget = newTarget;
mTarget->setEnabled(true);
mTarget->setWeight( 1.0 - mTimeleft / mDuration );
mTarget->setTimePosition(0);
}
}
else
{
// assert( target == 0, "target should be 0 when not blending" )
// mSource->setEnabled(true);
// mSource->setWeight(1);
mTransition = transition;
mTimeleft = mDuration = duration;
mTarget = newTarget;
mTarget->setEnabled(true);
mTarget->setWeight(0);
mTarget->setTimePosition(0);
}
}
}
void AnimationBlender::addTime( Real time )
{
if( mSource != 0 )
{
if( mTimeleft > 0 )
{
mTimeleft -= time;
if( mTimeleft < 0 )
{
// finish blending
mSource->setEnabled(false);
mSource->setWeight(0);
mSource = mTarget;
mSource->setEnabled(true);
mSource->setWeight(1);
mTarget = 0;
}
else
{
// still blending, advance weights
mSource->setWeight(mTimeleft / mDuration);
mTarget->setWeight(1.0 - mTimeleft / mDuration);
if(mTransition == AnimationBlender::BlendWhileAnimating)
mTarget->addTime(time);
}
}
if (mSource->getTimePosition() >= mSource->getLength())
{
complete = true;
}
else
{
complete = false;
}
mSource->addTime(time);
mSource->setLoop(loop);
}
}
AnimationBlender::AnimationBlender( Entity *entity ) : mEntity(entity)
{
}
AnimationBlenderDemo.h
#ifndef __ANIMATIONBLENDER_DEMO_H__
#define __ANIMATIONBLENDER_DEMO_H__
#include "ExampleApplication.h"
#include "AnimationBlender.h"
class AnimationBlenderDemoFrameListener : public ExampleFrameListener
{
protected:
Entity* mNinjaEnt;
AnimationBlender* mAnimationBlender;
bool walking, jumping;
public:
AnimationBlenderDemoFrameListener(RenderWindow* mWin, Camera* mCam, Entity* ent)
: ExampleFrameListener(mWin, mCam, false, false), mNinjaEnt(ent)
{
mAnimationBlender = new AnimationBlender(mNinjaEnt);
mAnimationBlender->init("Walk", true);
walking = false;
jumping = false;
}
virtual ~AnimationBlenderDemoFrameListener()
{
if(mAnimationBlender)
{
// delete mAnimationBlender;
}
}
bool frameRenderingQueued(const FrameEvent& evt)
{
if (!ExampleFrameListener::frameRenderingQueued(evt))
{
return false;
}
if (!walking)
{
mAnimationBlender->blend( "Walk",AnimationBlender::BlendWhileAnimating, 0.2, true );
walking=true;
}
if (mKeyboard->isKeyDown( OIS::KC_SPACE ) && !jumping)
{
jumping=true;
mAnimationBlender->blend("Jump",AnimationBlender::BlendWhileAnimating, 0.2, false );
}
if (jumping)
{
if (mAnimationBlender->complete)
{
mAnimationBlender->blend( "Idle1",AnimationBlender::BlendWhileAnimating, 0.02, true );
jumping=false;
}
}
mAnimationBlender->addTime(evt.timeSinceLastFrame);
return true;
}
};
class AnimationBlenderDemoApp : public ExampleApplication
{
public:
AnimationBlenderDemoApp() {}
protected:
Entity* mNinjaEnt;
void createScene();
void createFrameListener()
{
mFrameListener = new AnimationBlenderDemoFrameListener(mWindow, mCamera, mNinjaEnt);
mRoot->addFrameListener(mFrameListener);
}
};
#endif
AnimationBlenderDemo.cpp
#include "AnimationBlenderDemo.h"
#include <OgreStringConverter.h>
void AnimationBlenderDemoApp::createScene()
{
mSceneMgr->setAmbientLight(ColourValue(1.0, 1.0, 1.0));
mNinjaEnt = mSceneMgr->createEntity("Ninja", "ninja.mesh");
SceneNode* node = mSceneMgr->getRootSceneNode()->createChildSceneNode();
node->attachObject(mNinjaEnt);
}
#ifdef __cplusplus
extern "C" {
#endif
#if OGRE_PLATFORM == OGRE_PLATFORM_WIN32
#define WIN32_LEAN_AND_MEAN
#include "windows.h"
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR strCmdLine, INT )
#else
int main(int argc, char **argv)
#endif
{
AnimationBlenderDemoApp app;
try {
app.go();
} catch( Ogre::Exception& e ) {
#if OGRE_PLATFORM == OGRE_PLATFORM_WIN32
MessageBox( NULL, e.getFullDescription().c_str(), "An exception has occured!", MB_OK | MB_ICONERROR | MB_TASKMODAL );
#else
std::cerr << "An exception has occured: " << e.getFullDescription();
#endif
}
return 0;
}
#ifdef __cplusplus
}
#endif