jitterNode/jitterNode.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 dependency graph node "jitter".
//
// This plug-in is an example of a user-defined procedural dependency graph node.
// It is primarily oriented toward animation, but can be used to add noise in any
// connection between two float attributes. It takes a float value as input, 
// adds a pseudo-random value to the input, and outputs the noisy float value.
// For example, if the output of a parameter curve node is connected to the input
// of the jitter node and the output of the jitter node is connected to
// the translateX attribute of a surface, the motion of the surface will "jitter"
// parallel to the X axis.
//
// The node has one other input, "time". The output of the time slider node, "time1.outTime",
// must be connected to the time attribute on the jitter node if the "jittered" animation
// is to be repeatable. The attribute "scale" can be used to increase or decrease the
// magnitude of the random offset applied to the input of the jitter node.
//  
// Once the plug-in is loaded, the following MEL command creates the jitter node "jitter1",
// attaches the attribute "someNode1.outFloat" to "jitter1.input", and attaches 
// "jitter1.output" to "someNode2.inFloat":
//
//  jitter "jitter1" "someNode1.outFloat" "someNode2.inFloat";
// 
// It also attaches the time slider output "time1.outTime" to "jitter1.time" and "jitter2.time".
// Additionally, it creates two windows with sliders for adjusting the scale.
//
// The jitter node can be easily demonstrated in conjunction with the circleNode plug-in.
// Load the circleNode and jitterNode plug-ins. Then, execute the following commands:
//
//  source circleNode
//  source jitterNode
//  createSphereAndAttachCircleNode;
//  jitter "jitter1" "circleNode1.sineOutput" "sphere1.translateX";
//  jitter "jitter2" "circleNode1.cosineOutput" "sphere1.translateZ";
//
// Clicking the "play" icon on the time slider will cause the sphere to move along a "jittered" circle.
// The amount of jitter can be varied by adjusting the scale sliders in the 
// "jitter1 Scale Editor" and "jitter2 Scale Editor" windows.
//
// Attributes ( < input, > output ):
// 
//  < input: the input float value
//  < scale: the scalar for the random value (0 - 1.0)
//  < time: the frame number
// 
//  > output: the randomized float value
// 
// Usage:
// 
//  Use "jitterNode.mel" to insert this DG node between
//  a float value connection in your DG.
//

#include <string.h>
#include <stdio.h>
#include <maya/MIOStream.h>

#include <maya/MPxNode.h>

#include <maya/MString.h> 
#include <maya/MTypeId.h> 
#include <maya/MPlug.h>

#include <maya/MFnNumericAttribute.h>
#include <maya/MVector.h>

#include <maya/MFnPlugin.h>
#include <maya/MDataBlock.h>
#include <maya/MDataHandle.h>

static unsigned int xRand, yRand, zRand;     /* seed */

float randomd()
{
    float result;
    unsigned int a = xRand/177, b = xRand%177;
    unsigned int c = yRand/176, d = yRand%176;
    unsigned int e = zRand/178, f = zRand%178;

    xRand = (171 * b - 2 * a) % 30269;
    yRand = (172 * d - 35 * c) % 30307;
    zRand = (170 * f - 63 * e) % 30323;

    result = (float) xRand/30269.0f + yRand/30307.0f + zRand/30323.0f;
    return result - ((int) result);
}

void seedd(unsigned char nx, unsigned char ny, unsigned char nz)
{
    xRand = nx;
    yRand = ny;
    zRand = nz;
    randomd();
    randomd();
    randomd();
    randomd();
}

class jitter : public MPxNode
{
public:
    jitter();
    virtual ~jitter(); 

    virtual MStatus     compute( const MPlug& plug, MDataBlock& data );

    static  void*       creator();
    static  MStatus     initialize();
 
    static  MObject     time;       // The time value.
    static  MObject     scale;      // Scale of jitter.

    static  MObject     input;      // The input value.
    static  MObject     output;     // The jittered-output value.

    static  MTypeId     id;
};

MTypeId     jitter::id( 0x80009 );
MObject     jitter::time;
MObject     jitter::scale;
MObject     jitter::input;
MObject     jitter::output; 

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

MStatus jitter::initialize()
{
    MFnNumericAttribute nAttr;
    MStatus             stat;

    time = nAttr.create( "time", "tm", MFnNumericData::kFloat, 0.0 );
    nAttr.setStorable(true);

    scale = nAttr.create( "scale", "sc", MFnNumericData::kFloat, 1.0 );
    nAttr.setStorable(true);

    input = nAttr.create( "input", "in", MFnNumericData::kFloat, 0.0 );
    nAttr.setStorable(true);

    output = nAttr.create( "output", "out", MFnNumericData::kFloat, 0.0 );
    nAttr.setWritable(false);
    nAttr.setStorable(false);

    stat = addAttribute( time );
        if (!stat) { stat.perror("addAttribute"); return stat;}
    stat = addAttribute( scale );
        if (!stat) { stat.perror("addAttribute"); return stat;}
    stat = addAttribute( input );
        if (!stat) { stat.perror("addAttribute"); return stat;}
    stat = addAttribute( output );
        if (!stat) { stat.perror("addAttribute"); return stat;}

    stat = attributeAffects( time, output );
        if (!stat) { stat.perror("attributeAffects"); return stat;}
    stat = attributeAffects( scale, output );
        if (!stat) { stat.perror("attributeAffects"); return stat;}
    stat = attributeAffects( input, output );
        if (!stat) { stat.perror("attributeAffects"); return stat;}

    return MS::kSuccess;
} 

jitter::jitter() {}

jitter::~jitter() {}

// Compute the offset and add it to input
// as the output from this node.
MStatus jitter::compute( const MPlug& plug, MDataBlock& data )
{
    MStatus returnStatus;
 
    if( plug == output )
    {
        MDataHandle timeData = data.inputValue( time, &returnStatus );
        MDataHandle scaleData = data.inputValue( scale, &returnStatus );
        MDataHandle inputData = data.inputValue( input, &returnStatus );

        if( returnStatus != MS::kSuccess )
            cerr << "ERROR getting data\n";
        else
        {
            float currentFrame = timeData.asFloat();
            float scaleFactor  = scaleData.asFloat();
            float inValue = inputData.asFloat();

            // This is where we jitter the value

            unsigned char seed = (unsigned char)currentFrame;
            seedd( seed, seed * 17, seed * 23 );

            float tmp = randomd();
            float result = ( tmp - 0.5f ) * scaleFactor + inValue;

            MDataHandle outHandle = data.outputValue( jitter::output );

            outHandle.set( result );

            data.setClean(plug);
        }
    }
    else {
        return MS::kUnknownParameter;
    }

    return MS::kSuccess;
}

MStatus initializePlugin( MObject obj )
{ 
    MStatus   status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "3.0", "Any");

    status = plugin.registerNode( "jitter", jitter::id, 
                         jitter::creator, jitter::initialize  );
    if (!status) {
        status.perror("registerNode");
        return status;
    }

    return status;
}

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

    status = plugin.deregisterNode( jitter::id );
    if (!status) {
        status.perror("deregisterNode");
        return status;
    }

    return status;
}