geometrySurfaceConstraint/geometrySurfaceConstraint.cpp

//-
// ==========================================================================
// Copyright 2015 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.
// ==========================================================================
//+

#include "geometrySurfaceConstraint.h"

//
// DESCRIPTION:
//
// Produces the MPxConstraint node "geometrySurfaceConstraint" and MEL command "geometrySurfaceConstraint".

// This example demonstrates how to use the MPxConstraint and MPxConstraintCommand classes to create a 
// geometry constraint. This type of constraint will keep the constrained object attached to the target 
// as the target is moved. The constrained object can be constrained to one of multiple targets.
// You can choose to constrain to the target of the highest or lowest weight.
//
// To use this plug-in, first load it and then execute:
//
//  loadPlugin geometrySurfaceConstraint;
//
//  1. cylinder constrained to plane
//  file -f -new;
//  polyPlane -w 1 -h 1 -sx 10 -sy 10 -ax 0 1 0 -cuv 2 -ch 1;
//  scale -r 15 15 15;
//  polyCylinder -r 1 -h 2 -sx 20 -sy 1 -sz 1 -ax 0 1 0 -rcp 0 -cuv 3 -ch 1;
//  select -cl;
//  select -r pPlane1 pCylinder1;
//  geometrySurfaceConstraint -weight 1;
//
//  2. cylinder constrained to one of two planes
//  depending on plane weight
//  file -f -new;
//  polyPlane -w 1 -h 1 -sx 10 -sy 10 -ax 0 1 0 -cuv 2 -ch 1;
//  scale -r 10 10 10;
//  polyPlane -w 1 -h 1 -sx 10 -sy 10 -ax 0 1 0 -cuv 2 -ch 1;
//  scale -r 15 15 15;
//  polyCylinder -r 1 -h 2 -sx 20 -sy 1 -sz 1 -ax 0 1 0 -rcp 0 -cuv 3 -ch 1;
//  select -cl;
//  select -r pPlane1 pPlane2 pCylinder1;
//  geometryConstraint -weight 1.0;
//  change plane weight to move constrained object
//  geometryConstraint -e -w 10.0 pPlane2 pCylinder1;
//

//
//  Node implementation
//

MTypeId     geometrySurfaceConstraint::id( 0x8103F );
MObject     geometrySurfaceConstraint::compoundTarget;        
MObject     geometrySurfaceConstraint::targetGeometry;       
MObject     geometrySurfaceConstraint::targetWeight;       
MObject     geometrySurfaceConstraint::constraintParentInverseMatrix;       
MObject     geometrySurfaceConstraint::constraintGeometry;       


geometrySurfaceConstraint::geometrySurfaceConstraint() 
{
    weightType = geometrySurfaceConstraintCommand::kLargestWeight;
}

geometrySurfaceConstraint::~geometrySurfaceConstraint() 
{
}

void geometrySurfaceConstraint::postConstructor()
{
}

MStatus geometrySurfaceConstraint::compute( const MPlug& plug, MDataBlock& block )
{   
    MStatus returnStatus;
 
    if ( plug == geometrySurfaceConstraint::constraintGeometry )
    {
        //
        block.inputValue(constraintParentInverseMatrix);
        //
        MArrayDataHandle targetArray = block.inputArrayValue( compoundTarget );
        unsigned int targetArrayCount = targetArray.elementCount();
        double weight,selectedWeight = 0;
        if ( weightType == geometrySurfaceConstraintCommand::kSmallestWeight )
            selectedWeight = FLT_MAX;
        MObject selectedMesh;
        unsigned int i;
        for ( i = 0; i < targetArrayCount; i++ )
        {
            MDataHandle targetElement = targetArray.inputValue();
            weight = targetElement.child(targetWeight).asDouble();
            if ( !equivalent(weight,0.0))
            {
                if ( weightType == geometrySurfaceConstraintCommand::kLargestWeight )
                {
                    if ( weight > selectedWeight )
                    {
                        MObject mesh = targetElement.child(targetGeometry).asMesh();
                        if ( !mesh.isNull() )
                        {
                            selectedMesh = mesh;
                            selectedWeight =  weight;
                        }
                    }
                }
                else
                {
                    if  ( weight < selectedWeight )
                    {
                        MObject mesh = targetElement.child(targetGeometry).asMesh();
                        if ( !mesh.isNull() )
                        {
                            selectedMesh = mesh;
                            selectedWeight =  weight;
                        }
                    }
                }
            }
            targetArray.next();
        }
        //
        if ( selectedMesh.isNull() )
        {
            block.setClean(plug);
        }
        else
        {
            // The transform node via the geometry attribute will take care of
            // updating the location of the constrained geometry.
            MDataHandle outputConstraintGeometryHandle = block.outputValue(constraintGeometry);
            outputConstraintGeometryHandle.setMObject(selectedMesh);
        }
    } 
    else 
    {
        return MS::kUnknownParameter;
    }

    return MS::kSuccess;
}

const MObject geometrySurfaceConstraint::weightAttribute() const
{
    return geometrySurfaceConstraint::targetWeight;
}

const MObject geometrySurfaceConstraint::targetAttribute() const
{
    return geometrySurfaceConstraint::compoundTarget;
}

void geometrySurfaceConstraint::getOutputAttributes(MObjectArray& attributeArray)
{
    attributeArray.clear();
    attributeArray.append( geometrySurfaceConstraint::constraintGeometry );
}

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

MStatus geometrySurfaceConstraint::initialize()
{
    MFnNumericAttribute nAttr;
    MStatus             status;

    // constraint attributes

    {   // Geometry: mesh, readable, not writable, delete on disconnect
        MFnTypedAttribute typedAttrNotWritable;
        geometrySurfaceConstraint::constraintGeometry =
            typedAttrNotWritable.create( "constraintGeometry", "cg", MFnData::kMesh, MObject::kNullObj, &status );  
        if (!status) { status.perror("typedAttrNotWritable.create:cgeom"); return status;}
        status = typedAttrNotWritable.setReadable(true);
        if (!status) { status.perror("typedAttrNotWritable.setReadable:cgeom"); return status;}
        status = typedAttrNotWritable.setWritable(false);
        if (!status) { status.perror("typedAttrNotWritable.setWritable:cgeom"); return status;}
        status = typedAttrNotWritable.setDisconnectBehavior(MFnAttribute::kDelete);
        if (!status) { status.perror("typedAttrNotWritable.setDisconnectBehavior:cgeom"); return status;}
    }
    {   // Parent inverse matrix: delete on disconnect
        MFnTypedAttribute typedAttr;
        geometrySurfaceConstraint::constraintParentInverseMatrix =
            typedAttr.create( "constraintPim", "ci", MFnData::kMatrix, MObject::kNullObj, &status );    
        if (!status) { status.perror("typedAttr.create:matrix"); return status;}
        status = typedAttr.setDisconnectBehavior(MFnAttribute::kDelete);
        if (!status) { status.perror("typedAttr.setDisconnectBehavior:cgeom"); return status;}

        // Target geometry: mesh, delete on disconnect
        geometrySurfaceConstraint::targetGeometry =
            typedAttr.create( "targetGeometry", "tg", MFnData::kMesh, MObject::kNullObj, &status );     
        if (!status) { status.perror("typedAttr.create:tgeom"); return status;}
        status = typedAttr.setDisconnectBehavior(MFnAttribute::kDelete);
        if (!status) { status.perror("typedAttr.setDisconnectBehavior:cgeom"); return status;}
    }
    {   // Target weight: double, min 0, default 1.0, keyable, delete on disconnect
        MFnNumericAttribute typedAttrKeyable;
        geometrySurfaceConstraint::targetWeight 
            = typedAttrKeyable.create( "weight", "wt", MFnNumericData::kDouble, 1.0, &status );
        if (!status) { status.perror("typedAttrKeyable.create:weight"); return status;}
        status = typedAttrKeyable.setMin( (double) 0 );
        if (!status) { status.perror("typedAttrKeyable.setMin"); return status;}
        status = typedAttrKeyable.setKeyable( true );
        if (!status) { status.perror("typedAttrKeyable.setKeyable"); return status;}
        status = typedAttrKeyable.setDisconnectBehavior(MFnAttribute::kDelete);
        if (!status) { status.perror("typedAttrKeyable.setDisconnectBehavior:cgeom"); return status;}
    }
    {   // Compound target(geometry,weight): array, delete on disconnect
        MFnCompoundAttribute compoundAttr;
        geometrySurfaceConstraint::compoundTarget = 
            compoundAttr.create( "target", "tgt",&status );
        if (!status) { status.perror("compoundAttr.create"); return status;}
        status = compoundAttr.addChild( geometrySurfaceConstraint::targetGeometry );
        if (!status) { status.perror("compoundAttr.addChild"); return status;}
        status = compoundAttr.addChild( geometrySurfaceConstraint::targetWeight );
        if (!status) { status.perror("compoundAttr.addChild"); return status;}
        status = compoundAttr.setArray( true );
        if (!status) { status.perror("compoundAttr.setArray"); return status;}
        status = compoundAttr.setDisconnectBehavior(MFnAttribute::kDelete);
        if (!status) { status.perror("typedAttrKeyable.setDisconnectBehavior:cgeom"); return status;}
    }

    status = addAttribute( geometrySurfaceConstraint::constraintParentInverseMatrix );
    if (!status) { status.perror("addAttribute"); return status;}
    status = addAttribute( geometrySurfaceConstraint::constraintGeometry );
    if (!status) { status.perror("addAttribute"); return status;}
    status = addAttribute( geometrySurfaceConstraint::compoundTarget );
    if (!status) { status.perror("addAttribute"); return status;}

    status = attributeAffects( compoundTarget, constraintGeometry );
    if (!status) { status.perror("attributeAffects"); return status;}
    status = attributeAffects( targetGeometry, constraintGeometry );
    if (!status) { status.perror("attributeAffects"); return status;}
    status = attributeAffects( targetWeight, constraintGeometry );
    if (!status) { status.perror("attributeAffects"); return status;}
    status = attributeAffects( constraintParentInverseMatrix, constraintGeometry );
    if (!status) { status.perror("attributeAffects"); return status;}

    return MS::kSuccess;
}

//
//  Command implementation
//

geometrySurfaceConstraintCommand::geometrySurfaceConstraintCommand() {}
geometrySurfaceConstraintCommand::~geometrySurfaceConstraintCommand() {}

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

void geometrySurfaceConstraintCommand::createdConstraint(MPxConstraint *constraint)
{
    if ( constraint )
    {
        geometrySurfaceConstraint *c = (geometrySurfaceConstraint*) constraint;
        c->weightType = weightType;
    }
    else
    {
        MGlobal::displayError("Failed to get created constraint.");
    }
}


MStatus geometrySurfaceConstraintCommand::parseArgs(const MArgList &argList)
{
    MStatus         ReturnStatus;
    MArgDatabase    argData(syntax(), argList, &ReturnStatus);

    if ( ReturnStatus.error() )
        return MS::kFailure;

    // Settings only work at creation time. Would need an
    // attribute on the node in order to push this state
    // into the node at any time.
    ConstraintType typ;
    if (argData.isFlagSet(kConstrainToLargestWeightFlag))
        typ = geometrySurfaceConstraintCommand::kLargestWeight;
    else if (argData.isFlagSet(kConstrainToSmallestWeightFlag))
        typ = geometrySurfaceConstraintCommand::kSmallestWeight;
    else
        typ = geometrySurfaceConstraintCommand::kLargestWeight;
    weightType = typ;

    // Need parent to process
    return MS::kUnknownParameter;
}

MStatus geometrySurfaceConstraintCommand::doIt(const MArgList &argList)
{
    MStatus ReturnStatus;

    if ( MS::kFailure == parseArgs(argList) )
        return MS::kFailure;

    return MS::kUnknownParameter;
}

MStatus geometrySurfaceConstraintCommand::connectTarget(MDagPath& opaqueTarget, int index)
{
    try
    {
        MObject targetObject = opaqueTarget.node();
        MFnDagNode targetDagNode(targetObject);
        MObject targetAttribute = targetDagNode.attribute("worldMesh");

        MStatus status = connectTargetAttribute(
            opaqueTarget,
            index,
            targetAttribute,
            geometrySurfaceConstraint::targetGeometry,
            false);

        if (!status)
        {
            status.perror("connectTargetGeometry");
            return status;
        }
    }
    catch (...)
    {
        return MS::kFailure;
    }

    return MS::kSuccess;
}

MStatus geometrySurfaceConstraintCommand::connectObjectAndConstraint( MDGModifier& modifier )
{
    MObject transform = transformObject();
    if ( transform.isNull() )
    {
        MGlobal::displayError("Failed to get transformObject()");
        return MS::kFailure;
    }

    MStatus status;
    MFnTransform transformFn( transform );
    MVector translate = transformFn.getTranslation(MSpace::kTransform,&status);
    if (!status) { status.perror(" transformFn.getTranslation"); return status;}

    MPlug translatePlug = transformFn.findPlug( "translate",  true,  &status );
    if (!status) { status.perror(" transformFn.findPlug"); return status;}

    if ( MPlug::kFreeToChange == translatePlug.isFreeToChange() )
    {
        MFnNumericData nd;
        MObject translateData = nd.create( MFnNumericData::k3Double, &status );
        status = nd.setData3Double( translate.x,translate.y,translate.z);
        if (!status) { status.perror("nd.setData3Double"); return status;}
        status = modifier.newPlugValue( translatePlug, translateData );
        if (!status) { status.perror("modifier.newPlugValue"); return status;}

        status = connectObjectAttribute( 
            MPxTransform::geometry, 
                    geometrySurfaceConstraint::constraintGeometry, false );
        if (!status) { status.perror("connectObjectAttribute"); return status;}
    }

    status = connectObjectAttribute( 
        MPxTransform::parentInverseMatrix,
            geometrySurfaceConstraint::constraintParentInverseMatrix, true, true );
    if (!status) { status.perror("connectObjectAttribute"); return status;}

    return MS::kSuccess;
}

const MObject& geometrySurfaceConstraintCommand::constraintInstancedAttribute() const
{
    return geometrySurfaceConstraint::constraintParentInverseMatrix;
}

const MObject& geometrySurfaceConstraintCommand::constraintOutputAttribute() const
{
    return geometrySurfaceConstraint::constraintGeometry;
}

const MObject& geometrySurfaceConstraintCommand::constraintTargetInstancedAttribute() const
{
    return geometrySurfaceConstraint::targetGeometry;
}

const MObject& geometrySurfaceConstraintCommand::constraintTargetAttribute() const
{
    return geometrySurfaceConstraint::compoundTarget;
}

const MObject& geometrySurfaceConstraintCommand::constraintTargetWeightAttribute() const
{
    return geometrySurfaceConstraint::targetWeight;
}

const MObject& geometrySurfaceConstraintCommand::objectAttribute() const
{
    return MPxTransform::geometry;
}

MTypeId geometrySurfaceConstraintCommand::constraintTypeId() const
{
    return geometrySurfaceConstraint::id;
}

MPxConstraintCommand::TargetType geometrySurfaceConstraintCommand::targetType() const
{
    return MPxConstraintCommand::kGeometryShape;
}

MStatus geometrySurfaceConstraintCommand::appendSyntax()
{
    MStatus ReturnStatus;

    MSyntax theSyntax = syntax(&ReturnStatus);
    if (MS::kSuccess != ReturnStatus) {
        MGlobal::displayError("Could not get the parent's syntax");
        return ReturnStatus;
    }

    // Add our command flags
    theSyntax.addFlag( kConstrainToLargestWeightFlag, kConstrainToLargestWeightFlagLong );
    theSyntax.addFlag( kConstrainToSmallestWeightFlag, kConstrainToSmallestWeightFlagLong );

    return ReturnStatus;
}

//
//  Entry points
//

MStatus initializePlugin( MObject obj )
{ 
    MStatus   status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "9.0", "Any");

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

    status = plugin.registerConstraintCommand( "geometrySurfaceConstraint", geometrySurfaceConstraintCommand::creator );
    if (!status) {
        status.perror("registerConstraintCommand");
        return status;
    }

    return status;
}

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

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

    status = plugin.deregisterConstraintCommand( "geometrySurfaceConstraint" );
    if (!status) {
        status.perror("deregisterNode");
        return status;
    }

    return status;
}