用maya API删除动画曲线多余的关键帧——掐头去尾删帧_maya自动删除中间过度关键帧

写这个东西的缘由是一个同事给我说了一个他以前碰到的一个问题：一个文件里有上万条动画曲线，要删除某一帧前面的帧，也要删掉某一帧后面的帧，相当于是掐头去尾，但从功能上来说这个mel完全可以胜任，但是执行起来效率就特别的低，于是他找另一个同事帮他写了个command，这样就将一个6G的含有上万条动画曲线的文件，只用了40多分钟就删完了，最后只剩下1G，而用mel删了一个小时还不到10%，可见二者效率相差。于是自己也想试着写一些，真正写起来没啥难点，主要是两个类，MFnAnimCurve和MAnimCurveChange，同时也实现了redo和undo，实现这个主要是用一个指针在堆中创建一个内存空间，然后将removekey都缓存到这块内存空间里，最后用它自身方法就可以实现redo和undo，自己测试，我这个command效率上没有他的那个夸张，应该是有些地方还不够优化，后面再继续完善吧。想想自己和他们的距离，不，那是天堑，自己还得多加努力啊。具体代码如下：

#include<maya/MPxCommand.h>
#include <maya/MFnPlugin.h>
#include <maya/MSyntax.h>
#include <maya/MDistance.h>
#include <maya/MItDependencyNodes.h>
#include <maya/MDGModifier.h>
#include <maya/MArgDatabase.h>
#include <maya/MFnAnimCurve.h>
#include <maya/MAnimCurveChange.h>
 
class DeleteKeysCmd : public MPxCommand
{
public:
    DeleteKeysCmd();
    ~DeleteKeysCmd();
    virtual MStatus doIt( const MArgList& );
    virtual MStatus redoIt();
    virtual MStatus undoIt();
    virtual bool isUndoable() const { return true; };
    static void *creator(){ return new DeleteKeysCmd; }
    static MSyntax newSyntax();
 
private:
    MTime startFrame;
    MTime endFrame;
    MAnimCurveChange* pAnimCache;
 
};
 
const char *startFrameFlag = "-sf", *startFrameLongFlag = "-startFrame";
const char *newendFrameFlag = "-ef", *newendFrameLongFlag = "-endFrame";
 
DeleteKeysCmd::DeleteKeysCmd()
{
    startFrame.setValue( 0 );
    endFrame.setValue( 100 );
}
 
DeleteKeysCmd::~DeleteKeysCmd()
{
    delete pAnimCache;
}
 
MSyntax DeleteKeysCmd::newSyntax()
{
    MSyntax syntax;
    syntax.addFlag( startFrameFlag, startFrameLongFlag, MSyntax::kLong );
    syntax.addFlag( newendFrameFlag, newendFrameLongFlag, MSyntax::kLong );
 
    return syntax;
}
 
MStatus DeleteKeysCmd::doIt( const MArgList &args )
{
    MStatus stat;
    pAnimCache = NULL;
    pAnimCache = new MAnimCurveChange();
 
    MArgDatabase argData( syntax(), args, &stat );
    if( !stat )
        return stat;
    if( argData.isFlagSet( startFrameFlag ) )
        argData.getFlagArgument( startFrameFlag, 0,  startFrame);
    if( argData.isFlagSet( newendFrameLongFlag ) )
        argData.getFlagArgument( newendFrameLongFlag, 0,  endFrame);
 
    MDGModifier modifier;
    MItDependencyNodes animCurves(MFn::kAnimCurve);
    
    for (; !animCurves.isDone(); animCurves.next())
    {
        MObject currentItem = animCurves.item();
        if ( currentItem.isNull() )
        {
            continue;
        }
        MFnAnimCurve fnCurve (currentItem);
        unsigned int numKeys = fnCurve.numKeys();
        if (numKeys == 0)
        {
            modifier.deleteNode(currentItem);
        }
        else
        {
            unsigned int startFrameIndex = fnCurve.findClosest(startFrame);
            for(unsigned int i = 0; i < startFrameIndex; i++)
            {
                fnCurve.remove(0, pAnimCache);
            }
            unsigned int endFrameIndex = fnCurve.findClosest(endFrame);
            unsigned int numKeysToRemoves = numKeys -1 - endFrameIndex;
            for(unsigned int i = 0; i < numKeysToRemoves; i++)
            {
                fnCurve.remove(endFrameIndex + 1, pAnimCache);
            }
        }
    }
    return stat;
}
 
MStatus DeleteKeysCmd::undoIt()
{
    if( pAnimCache != NULL )
        pAnimCache -> undoIt();
    return MS::kSuccess;
}
 
MStatus DeleteKeysCmd::redoIt()
{
    if( pAnimCache != NULL )
        pAnimCache -> redoIt();
    return MS::kSuccess;
}
 
MStatus initializePlugin( MObject obj )
{
    MFnPlugin plugin( obj, "Lulongfei", "1.0" );
    MStatus stat;
    stat = plugin.registerCommand( "deleteKeys", DeleteKeysCmd::creator, DeleteKeysCmd::newSyntax );
    if ( !stat )
        stat.perror( "registerCommand failed" );
    return stat;
}
 
MStatus uninitializePlugin( MObject obj )
{
    MFnPlugin plugin( obj );
    MStatus stat;
    stat = plugin.deregisterCommand( "deleteKeys" );
    if ( !stat )
        stat.perror( "deregisterCommand failed" );
    return stat;
}

def removeInvalidKeys(start, end):
        animCurves = om.MItDependencyNodes(om.MFn.kAnimCurve)
        while not animCurves.isDone():
            modifier = om.MDGModifier()
            fnCurveCache = oma.MAnimCurveChange()
            currentItem = animCurves.item()
            fnCurve = oma.MFnAnimCurve(currentItem)
    
            if fnCurve.numKeys():
                # remove all frame before the start keyframe
                startFrameIndex = fnCurve.findClosest(om.MTime(start))
                for i in xrange(startFrameIndex):
                    fnCurve.remove(0, fnCurveCache)
    
                # remove all frame after the end keyframe
                endFrameIndex = fnCurve.findClosest(om.MTime(end))
                for i in xrange(endFrameIndex, fnCurve.numKeys() - 1):
                    fnCurve.remove(endFrameIndex + 1, fnCurveCache)
                    #fnCurveCache.undoIt()
            
            else:
                modifier.deleteNode(currentItem)
            
            animCurves.next()

而python则直接可以调用function了，removeInvalidKeys（20， 90）