componentScaleManip/componentScaleManip.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:
//
// This example demonstrates the scale manipulator in the API. This example 
// uses three classes to accomplish this task: First, a context command 
// (componentScaleContext) is provided to create instances of the context.  
// Next, a custom selection context (ComponentScaleContext) is created to 
// manage the component scale manipulator. Finally, the component scale  
// manipulator is provided as a custom node class.
//
// Loading and unloading:
// ----------------------
//
// The component scale manipulator context can be created with the following
// MEL commands:
//
//  componentScaleContext;
//  setToolTo componentScaleContext1;
//
// If the preceding commands were used to create the manipulator context, 
// the following commands can destroy it:
//
//  deleteUI componentScaleContext1;
//  deleteUI componentScaleManip;
//
// If the plug-in is loaded and unloaded frequently (such as during testing),
// it is useful to make these command sequences into shelf buttons.
//
// To create the tool button for the plug-in: 
//  
//  setParent Shelf1;
//  toolButton -cl toolCluster -t componentScaleContext1 -i1 "moveManip.xpm";
//
// How to use:
// -----------
//
// Once the tool button has been created using the script above, select the
// tool button, and then select some object components. If non-components are 
// selected, warning messages will be printed indicating that no manipulatable
// objects are selected. Once components are selected, the scale manipulator
// will appear at the centroid of the components. Then, the manipulator can
// be used much like the built-in scale manipulator.
//
// Currently, this plug-in only works correctly for NURBS surfaces where the 
// parametization has the distance 1.0 corresponding to the distance between CVs.
// This will be the case for NURBS spheres, torus, and cones. Planes and
// cylinders do not have this property.
//
// Note that undo and redo are not supported in this example plug-in.
//  

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

#include <maya/MFn.h>
#include <maya/MPxNode.h>
#include <maya/MPxManipContainer.h>
#include <maya/MPxSelectionContext.h>
#include <maya/MPxContextCommand.h>
#include <maya/MModelMessage.h>
#include <maya/MFnPlugin.h>
#include <maya/MGlobal.h>
#include <maya/MItSelectionList.h>
#include <maya/MPoint.h>
#include <maya/MVector.h>
#include <maya/MDagPath.h>
#include <maya/MManipData.h>
#include <maya/MSelectionList.h>
#include <maya/MItSurfaceCV.h>
#include <maya/MFnComponent.h>

// Manipulators
#include <maya/MFnScaleManip.h>

// This function is a utility that can be used to extract vector values from
// plugs.
//
MVector vectorPlugValue(const MPlug& plug) {
    if (plug.numChildren() == 3)
    {
        double x,y,z;
        MPlug rx = plug.child(0);
        MPlug ry = plug.child(1);
        MPlug rz = plug.child(2);
        rx.getValue(x);
        ry.getValue(y);
        rz.getValue(z);
        MVector result(x,y,z);
        return result;
    }
    else {
        MGlobal::displayError("Expected 3 children for plug "+MString(plug.name()));
        MVector result(0,0,0);
        return result;
    }
}

//
// componentScaleManip
//
// This class implements the component scaling example.
//

class componentScaleManip : public MPxManipContainer
{
public:
    componentScaleManip();
    ~componentScaleManip() override;
    
    static void * creator();
    static MStatus initialize();
    MStatus createChildren() override;
    MStatus connectToDependNode(const MObject &node) override;

    void draw(M3dView &view, 
                      const MDagPath &path, 
                      M3dView::DisplayStyle style,
                      M3dView::DisplayStatus status) override;

    void setSurfaceDagPath(const MDagPath& dagPath) {
        surfaceDagPath = dagPath;
    }

    void setComponentObject(const MObject& obj) {
        component = obj;
    }

    // Virtual handlers
    MManipData manipToPlugConversion(unsigned index) override;
    MManipData plugToManipConversion(unsigned index) override;

    MDagPath fScaleManip;

public:
    static MTypeId id;

private:

    MDagPath surfaceDagPath;
    MObject component;

    MPoint centroid;

    int numComponents;
    MPoint* initialPositions;
    MPoint* initialControlPoint;

    unsigned dummyPlugIndex;
};


MTypeId componentScaleManip::id( 0x80021 );

componentScaleManip::componentScaleManip() : numComponents(0)
,   initialPositions(NULL)
,   initialControlPoint(NULL)
{ 
    // The constructor must not call createChildren for user-defined
    // manipulators.
}


componentScaleManip::~componentScaleManip() 
{
    // initialPositions should always be either NULL or an allocated array
    // of MPoint.
    //
    delete [] initialPositions;
    delete [] initialControlPoint;
}


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


MStatus componentScaleManip::initialize()
{ 
    MStatus stat;
    stat = MPxManipContainer::initialize();
    return stat;
}


MStatus componentScaleManip::createChildren()
{
    MStatus stat = MStatus::kSuccess;

    fScaleManip = addScaleManip("scaleManip", "scale");

    return stat;
}


MStatus componentScaleManip::connectToDependNode(const MObject &node)
{
    MStatus stat;
    
    MFnComponent componentFn(component);
    if (componentFn.elementCount() > numComponents)
    {
        delete [] initialPositions;
        delete [] initialControlPoint;
        numComponents = componentFn.elementCount();
        initialPositions = new MPoint[numComponents];
        initialControlPoint = new MPoint[numComponents];
    }

    // Iterate through the components, storing initial positions and find the
    // centroid.  Add manipToPlug callbacks for each component.
    //
    int i = 0;
    for (MItSurfaceCV iter(surfaceDagPath, component); !iter.isDone(); iter.next(), i++)
    {
        if (i >= numComponents)
        {
            MGlobal::displayWarning("More components found than expected.");
            break;
        }
        initialPositions[i] = iter.position(MSpace::kWorld);
        centroid += initialPositions[i];

        //
        // Create a manipToPlug callback that is invoked whenever the manipVal
        // changes.  The callback is added for every selected CV.
        //

        MFnDependencyNode nodeFn(node);
        MPlug controlPointArrayPlug = nodeFn.findPlug("controlPoints",  true,  &stat);
        if (controlPointArrayPlug.isNull())
        {
            MGlobal::displayError("Control point plug not found on node.");
            return MS::kFailure;
        }

        // The logical index from the component iterator is the same as the
        // logical index into the control points array.
        //
        MPlug controlPointPlug = 
            controlPointArrayPlug.elementByLogicalIndex(iter.index(), &stat);
        if (controlPointPlug.isNull())
        {
            MGlobal::displayError("Control point element not found.");
            return MS::kFailure;
        }

        // Store the initial value of the control point.
        //
        initialControlPoint[i] = vectorPlugValue(controlPointPlug);

        unsigned plugIndex = addManipToPlugConversion(controlPointPlug);

        // Plug indices should be allocated sequentially, starting at 0.  Each
        // manip container will have its own set of plug indices.  This code 
        // relies on the sequential allocation of indices, so trigger an error
        // if the indices are found to be different.
        //
        if (plugIndex != (unsigned)i)
        {
            MGlobal::displayError("Unexpected plug index returned.");
            return MS::kFailure;
        }
    }
    centroid = centroid / numComponents;

    MFnScaleManip scaleManip(fScaleManip);

    // Create a plugToManip callback that places the manipulator at the 
    // centroid of the CVs.
    //
    addPlugToManipConversion(scaleManip.scaleCenterIndex());

    finishAddingManips();
    MPxManipContainer::connectToDependNode(node);
    return stat;
}


void componentScaleManip::draw(M3dView & view, 
                     const MDagPath & path, 
                     M3dView::DisplayStyle style,
                     M3dView::DisplayStatus status)
{
    MPxManipContainer::draw(view, path, style, status);
}

MManipData componentScaleManip::plugToManipConversion(unsigned index) {
    MObject obj = MObject::kNullObj;

    // If we entered the callback with an invalid index, print an error and
    // return.  Since we registered the callback only for one index, all 
    // invocations of the callback should be for that index.
    //
    MFnScaleManip scaleManip(fScaleManip);
    if (index == scaleManip.scaleCenterIndex())
    {
        // Set the center point for scaling to the centroid of the CV's.
        //
        MFnNumericData numericData;
        obj = numericData.create( MFnNumericData::k3Double );
        numericData.setData(centroid.x,centroid.y,centroid.z);

        return MManipData(obj);
    }

    MGlobal::displayError("Invalid index in plugToManipConversion()!");

    // For invalid indices, return vector of 0's
    MFnNumericData numericData;
    obj = numericData.create( MFnNumericData::k3Double );
    numericData.setData(0.0,0.0,0.0);

    return obj;
}

MManipData componentScaleManip::manipToPlugConversion(unsigned index) {
    MObject obj = MObject::kNullObj;

    MFnScaleManip scaleManip(fScaleManip);
    if (index < (unsigned)numComponents)
    {
        //
        // Now we need to determine the scaled position of the CV specified by 
        // index.
        //

        MVector scaleVal;
        getConverterManipValue(scaleManip.scaleIndex(), scaleVal);

        // Determine the vector from the centroid to the CV
        //
        MVector positionVec = initialPositions[index] - centroid;

        // Scale the vector
        //
        MVector newPosition(positionVec.x*scaleVal.x, 
            positionVec.y*scaleVal.y, positionVec.z*scaleVal.z);

        // Form the vector from the initial position to the new position.
        //
        newPosition = newPosition - positionVec;

        // Move the control point from the initial control point position along
        // the vector.  Control point positions are always measured relative to
        // the initial position of the control point, which is why a separate 
        // array of control point positions is required.
        //
        newPosition += initialControlPoint[index];

        MFnNumericData numericData;
        obj = numericData.create( MFnNumericData::k3Double );
        numericData.setData(newPosition.x,newPosition.y,newPosition.z);

        return MManipData(obj);
    }

    // If we entered the handler with an invalid index, print an error and
    // return.  The callback should only be called for indices from 0 to
    // numComponents-1.
    //

    MGlobal::displayError("Invalid index in scale changed callback!");

    // For invalid indices, return vector of 0's
    MFnNumericData numericData;
    obj = numericData.create( MFnNumericData::k3Double );
    numericData.setData(0.0,0.0,0.0);

    return obj;
    
}

//
// ComponentScaleContext
//
// This class is a simple context for supporting a scale manipulator.
//

class ComponentScaleContext : public MPxSelectionContext
{
public:
    ComponentScaleContext();
    void    toolOnSetup(MEvent &event) override;
    void    toolOffCleanup() override;

    // Callback issued when selection list changes
    static void updateManipulators(void * data);

private:
    MCallbackId id1;
};

ComponentScaleContext::ComponentScaleContext()
{
    MString str("Plugin component scaling manipulator");
    setTitleString(str);
}


void ComponentScaleContext::toolOnSetup(MEvent &)
{
    MString str("Scale the selected components");
    setHelpString(str);

    updateManipulators(this);
    MStatus status;
    id1 = MModelMessage::addCallback(MModelMessage::kActiveListModified,
                                     updateManipulators, 
                                     this, &status);
    if (!status) {
        MGlobal::displayError("Model addCallback failed");
    }
}


void ComponentScaleContext::toolOffCleanup()
{
    MStatus status;
    status = MModelMessage::removeCallback(id1);
    if (!status) {
        MGlobal::displayError("Model remove callback failed");
    }
    MPxContext::toolOffCleanup();
}


void ComponentScaleContext::updateManipulators(void * data)
{
    MStatus stat = MStatus::kSuccess;
    
    ComponentScaleContext * ctxPtr = (ComponentScaleContext *) data;
    ctxPtr->deleteManipulators(); 

    MSelectionList list;
    stat = MGlobal::getActiveSelectionList(list);
    MItSelectionList iter(list, MFn::kInvalid, &stat);

    if (MS::kSuccess == stat) {
        for (; !iter.isDone(); iter.next()) {

            // Make sure the selection list item is a dag path with components
            // before attaching the manipulator to it.
            //
            MDagPath dagPath;
            MObject components;
            iter.getDagPath(dagPath, components);

            if (components.isNull() || !components.hasFn(MFn::kComponent))
            {
                MGlobal::displayWarning("Object in selection list is not "
                    "a component.");
                continue;
            }

            // Add manipulator to the selected object
            //
            MString manipName ("componentScaleManip");
            MObject manipObject;
            componentScaleManip* manipulator =
                (componentScaleManip *) componentScaleManip::newManipulator(manipName, manipObject);

            if (NULL != manipulator) {
                // Add the manipulator
                //
                ctxPtr->addManipulator(manipObject);

                // Connect the manipulator to the object in the selection list.
                //
                manipulator->setSurfaceDagPath(dagPath);
                manipulator->setComponentObject(components);
                if (!manipulator->connectToDependNode(dagPath.node()))
                {
                    MGlobal::displayWarning("Error connecting manipulator to"
                        " object");
                }
            } 
        }
    }
}


//
// componentScaleContext
//
// This is the command that will be used to create instances
// of our context.
//

class componentScaleContext : public MPxContextCommand
{
public:
    componentScaleContext() {};
    MPxContext * makeObj() override;

public:
    static void* creator();
};

MPxContext *componentScaleContext::makeObj()
{
    return new ComponentScaleContext();
}

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


//
// The following routines are used to register/unregister
// the context and manipulator
//

MStatus initializePlugin(MObject obj)
{
    MStatus status;
    MFnPlugin plugin(obj, PLUGIN_COMPANY, "6.0", "Any");

    status = plugin.registerContextCommand("componentScaleContext",
                                           &componentScaleContext::creator);
    if (!status) {
        MGlobal::displayError("Error registering componentScaleContext command");
        return status;
    }

    status = plugin.registerNode("componentScaleManip", componentScaleManip::id, 
                                 &componentScaleManip::creator, &componentScaleManip::initialize,
                                 MPxNode::kManipContainer);
    if (!status) {
        MGlobal::displayError("Error registering componentScaleManip node");
        return status;
    }

    return status;
}


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

    status = plugin.deregisterContextCommand("componentScaleContext");
    if (!status) {
        MGlobal::displayError("Error deregistering componentScaleContext command");
        return status;
    }

    status = plugin.deregisterNode(componentScaleManip::id);
    if (!status) {
        MGlobal::displayError("Error deregistering componentScaleManip node");
        return status;
    }

    return status;
}