helixQtCmd.cpp

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

//  Must ensure that at least one Qt header is included before anything
//  else.
#include <helixQtCmd.h>

#include <math.h>
#include <maya/MDoubleArray.h> 
#include <maya/MFnDependencyNode.h>
#include <maya/MFnNurbsCurve.h>
#include <maya/MFnPlugin.h>
#include <maya/MGlobal.h>
#include <maya/MObject.h>
#include <maya/MPoint.h>
#include <maya/MPointArray.h>

// ==========================================================================
//
//          HelixButton class
//
// ==========================================================================

HelixButton::HelixButton(const QString& text, QWidget* parent)
:   QPushButton(text, parent)
{}

HelixButton::~HelixButton()
{}


//  This is a slot which is called whenever the button is pushed.
//  It creates a helical NURBS curve within Maya.
void HelixButton::createHelix(bool /* checked */)
{
    MStatus st;

    const unsigned deg    = 3;             // Curve Degree
    const unsigned ncvs   = 20;            // Number of CVs
    const unsigned spans  = ncvs - deg;    // Number of spans
    const unsigned nknots = spans+2*deg-1; // Number of knots
    double         radius = 4.0;           // Helix radius
    double         pitch  = 0.5;           // Helix pitch
    unsigned       i;

    MPointArray controlVertices;
    MDoubleArray knotSequences;

    // Set up cvs and knots for the helix
    for (i = 0; i < ncvs; i++) {
        controlVertices.append(
            MPoint(
                radius * cos((double) i),
                pitch * (double) i,
                radius * sin((double) i)
            )
        );
    }
    
    for (i = 0; i < nknots; i++)
        knotSequences.append((double) i);

    // Now create the curve
    MFnNurbsCurve curveFn;

    MObject curve = curveFn.create(
        controlVertices,
        knotSequences,
        deg,
        MFnNurbsCurve::kOpen,
        false,
        false,
        MObject::kNullObj,
        &st
    );

    if (!st) {
        MGlobal::displayError(
            HelixQtCmd::commandName + " - could not create helix: "
            + st.errorString()
        );
    }
}


// ==========================================================================
//
//          HelixQtCmd class
//
// ==========================================================================

//  We store a pointer to the button window in a static QPointer so that we
//  can destroy it if the plugin is unloaded. The QPointer will
//  automatically set itself to zero if the button window is destroyed
//  for any reason.
QPointer<HelixButton>   HelixQtCmd::button;

const MString           HelixQtCmd::commandName("helixQt");


//  Destroy the button window, if it still exists.
void HelixQtCmd::cleanup()
{
    if (!button.isNull()) delete button;
}


MStatus HelixQtCmd::doIt(const MArgList& /* args */)
{
    //  Create a window containing a HelixButton, if one does not already
    //  exist. Otherwise just make sure that the existing window is visible.
    if (button.isNull()) {
        button = new HelixButton("Create Helix");
        button->connect(button, SIGNAL(clicked(bool)), button, SLOT(createHelix(bool)));
        button->show();
    }
    else {
        button->showNormal();
        button->raise();
    }


    return MS::kSuccess;
}


// ==========================================================================
//
//          Plugin load/unload
//
// ==========================================================================

MStatus initializePlugin(MObject plugin)
{
    MStatus     st;
    MFnPlugin   pluginFn(plugin, "Autodesk, Inc.", "1.0", "Any", &st);

    if (!st) {
        MGlobal::displayError(
            MString("helixQtCmd - could not initialize plugin: ")
            + st.errorString()
        );
        return st;
    }

    //  Register the command.
    st = pluginFn.registerCommand(HelixQtCmd::commandName, HelixQtCmd::creator);

    if (!st) {
        MGlobal::displayError(
            MString("helixQtCmd - could not register '")
            + HelixQtCmd::commandName + "' command: "
            + st.errorString()
        );
        return st;
    }

    return st;
}


MStatus uninitializePlugin(MObject plugin)
{
    MStatus     st;
    MFnPlugin   pluginFn(plugin, "Autodesk, Inc.", "1.0", "Any", &st);

    if (!st) {
        MGlobal::displayError(
            MString("helixQtCmd - could not uninitialize plugin: ")
            + st.errorString()
        );
        return st;
    }

    //  Make sure that there is no UI left hanging around.
    HelixQtCmd::cleanup();

    //  Deregister the command.
    st = pluginFn.deregisterCommand(HelixQtCmd::commandName);

    if (!st) {
        MGlobal::displayError(
            MString("helixQtCmd - could not deregister '")
            + HelixQtCmd::commandName + "' command: "
            + st.errorString()
        );
        return st;
    }

    return st;
}