motionTraceCmd/motionTraceCmd.cpp

//-
// ==========================================================================
// Copyright 1995,2006,2008 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk
// license agreement provided at the time of installation or download,
// or which otherwise accompanies this software in either electronic
// or hard copy form.
// ==========================================================================
//+

// DESCRIPTION:
//
// Produces the MEL command "motionTrace". 
//
// Traces the position of an animated object and creates a curve showing the path of the object.
//
// To use this plug-in you must first create an object and animate it by setting keyframes.
// An easy way to do this is to just create a primitive and then set a bunch of keyframes for it
// with the "spiralAnimCurveCmd" plug-in. 
//
// To use this plug-in:
//
//  (1) Animate an object.
//  (2) Select the object.
//  (3) Run 'motionTrace;' in the command window.
//  (4) See the object's path drawn as a curve.
//
// Options:
//
//  -s <frame>      The start frame.  Default to 1.
//  -e <frame>      The end frame.  Default to 60.
//  -b <frame>      The by frame.  Default to 1.
//
// See also:
//
//  node_info.cc    for how to get object attributes
//  helix.cc        for how to create a curve
//

#include <maya/MIOStream.h>

#include <maya/MFnPlugin.h>
#include <maya/MString.h>
#include <maya/MArgList.h>

#include <maya/MPxCommand.h>

#include <maya/MGlobal.h>
#include <maya/MTime.h>
#include <maya/MDagPath.h>
#include <maya/MItSelectionList.h>
#include <maya/MSelectionList.h>

#include <maya/MFnDependencyNode.h>
#include <maya/MPlugArray.h>
#include <maya/MPlug.h>

#include <maya/MPoint.h>
#include <maya/MPointArray.h>
#include <maya/MDoubleArray.h>
#include <maya/MObjectArray.h>
#include <maya/MFnNurbsCurve.h>

//
// Command class declaration
//
class motionTrace : public MPxCommand
{
public:
                    motionTrace();
                ~motionTrace() override;

    MStatus         doIt( const MArgList& args ) override;
    MStatus         redoIt() override;

    static void*    creator();

private:
    void        printType( MObject node, MString & prefix );

    double          start, end, by; // frame range
};



//
// Command class implementation
//

motionTrace::motionTrace() {}

void* motionTrace::creator()
{
    return new motionTrace();
}

motionTrace::~motionTrace()
{
}

MStatus motionTrace::doIt( const MArgList& args )
//
// Description
//     This method is called from MEL when this command is called.
//     It should set up any class data necessary for redo/undo,
//     parse any given arguments, and then call redoIt.
//
{
    start = 1.0;
    end = 60.0;
    by = 1.0;

    MStatus stat;
    double tmp;
    unsigned i;
    // Parse the arguments.
    for ( i = 0; i < args.length(); i++ )
    {
        if ( MString( "-s" ) == args.asString( i, &stat ) &&
             MS::kSuccess == stat)
        {
            tmp = args.asDouble( ++i, &stat );
            if ( MS::kSuccess == stat )
            start = tmp;
        }
        else if ( MString( "-e" ) == args.asString( i, &stat ) &&
                  MS::kSuccess == stat)
        {
            tmp = args.asDouble( ++i, &stat );
            if ( MS::kSuccess == stat )
            end = tmp;
        }
        else if ( MString( "-b" ) == args.asString( i, &stat ) &&
                  MS::kSuccess == stat)
        {
            tmp = args.asDouble( ++i, &stat );
            if ( MS::kSuccess == stat )
            by = tmp;
        }
    }

    stat = redoIt();

    return stat;
}

/*
-----------------------------------------

    Make a degree 1 curve from the given CVs.

-----------------------------------------
*/
static void jMakeCurve( MPointArray cvs )
{
    MStatus stat;
    unsigned int deg = 1;
    MDoubleArray knots;

    unsigned int i;
    for ( i = 0; i < cvs.length(); i++ )
        knots.append( (double) i );

    // Now create the curve
    //
    MFnNurbsCurve curveFn;

    curveFn.create( cvs,
                    knots, deg,
                    MFnNurbsCurve::kOpen,
                    false, false,
                    MObject::kNullObj,
                    &stat );

    if ( MS::kSuccess != stat )
        cout<<"Error creating curve."<<endl;

}

MStatus motionTrace::redoIt()
//
// Description
//     This method performs the action of the command.
//
//     This method iterates over all selected items and
//     prints out connected plug and dependency node type
//     information.
//
{
    MStatus stat;               // Status code

    MObjectArray picked;
    MObject     dependNode;     // Selected dependency node

    // Create a selection list iterator
    //
    MSelectionList slist;
    MGlobal::getActiveSelectionList( slist );
    MItSelectionList iter( slist, MFn::kInvalid,&stat );

    // Iterate over all selected dependency nodes
    // and save them in a list
    //
    for ( ; !iter.isDone(); iter.next() )
    {
        // Get the selected dependency node
        //
        if ( MS::kSuccess != iter.getDependNode( dependNode ) )
        {
            cerr << "Error getting the dependency node" << endl;
            continue;
        }
        picked.append( dependNode );
    }

    // array of arrays for object position

    MPointArray *pointArrays = new MPointArray [ picked.length() ];

    unsigned int i;
    double time;

    //  Sample the animation using start, end, by values

    for ( time = start; time <= end; time+=by )
    {
        MTime timeval(time);

        MGlobal::viewFrame( timeval );

        // Iterate over selected dependency nodes
        //

        for ( i = 0; i < picked.length(); i++ )
        {
            // Get the selected dependency node
            //
            dependNode = picked[i];

            // Create a function set for the dependency node
            //
            MFnDependencyNode fnDependNode( dependNode );

            // Get the translation attribute values

            MObject txAttr;
            txAttr = fnDependNode.attribute( MString("translateX"), &stat );
            MPlug txPlug( dependNode, txAttr );
            double tx;
            stat = txPlug.getValue( tx );

            MObject tyAttr;
            tyAttr = fnDependNode.attribute( MString("translateY"), &stat );
            MPlug tyPlug( dependNode, tyAttr );
            double ty;
            stat = tyPlug.getValue( ty );

            MObject tzAttr;
            tzAttr = fnDependNode.attribute( MString("translateZ"), &stat );
            MPlug tzPlug( dependNode, tzAttr );
            double tz;
            stat = tzPlug.getValue( tz );

#if 0
            fprintf( stderr,
                     "Time = %2.2lf, XYZ = ( %2.2lf, %2.2lf, %2.2lf )\n\n",
                     time, tx, ty, tz );
#endif

            pointArrays[i].append( MPoint( tx, ty, tz )) ;
        }
    }

    // make a path curve for each selected object

    for ( i = 0; i < picked.length(); i++ )
        jMakeCurve( pointArrays[i] );

    delete [] pointArrays;
    return MS::kSuccess;
}


//
// The following routines are used to register/unregister
// the command we are creating within Maya
//
MStatus initializePlugin( MObject obj )
{
    MStatus   status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "3.0", "Any");

    status = plugin.registerCommand( "motionTrace", motionTrace::creator );
    if (!status) {
        status.perror("registerCommand");
        return status;
    }

    return status;
}

MStatus uninitializePlugin( MObject obj)
{
    MStatus   status;
    MFnPlugin plugin( obj );

    status =  plugin.deregisterCommand( "motionTrace" );
    if (!status) {
        status.perror("registerCommand");
        return status;
    }

    return status;
}