source: downloads/Tests/PlayPen/src/AnimationBlender.cpp @ 8

// from http://www.ogre3d.org/wiki/index.php/AnimationBlender

#include "AnimationBlender.h"
#include "OgreAnimationState.h"


using namespace Ogre;


void AnimationBlender::init(const String &animation)
{
        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;
} 
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
                {
                        if (mSource == newTarget)
                        {
                                mTimeleft = 0;
                                return;
                        }
                        // 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) {}