lineManip/lineManip.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.
// ==========================================================================
//+

//
//  lineManip.cpp
//      Creates manipulator node lineManip
//      Creates command lineManipCmd
//
//  This example demonstrates how to use the MPxManipulatorNode
//  class along with a command to create a user defined
//  manipulator.  The manipulator created is a simple line
//  which is an OpenGL pickable component.  As you
//  move the pickable component, selected transforms have
//  their scale attribute modified. The line's movements
//  are restricted in a plane.
//  A corresponding command is used to create and delete
//  the manipulator node and to support undo/redo etc.
 
/*

// To show this example using MEL, run the following:
loadPlugin lineManip.so;
lineManipCmd -create;

// To delete the manipulator using MEL:
lineManipCmd -delete;

*/

#include "lineManip.h"

#include <maya/MHardwareRenderer.h>
#include <maya/MIOStream.h>
#include <maya/MMatrix.h>
#include <maya/MPoint.h>
#include <maya/MVector.h>
#include <maya/MSelectionList.h>
#include <maya/MItSelectionList.h>
#include <maya/MFnTransform.h>
#include <maya/MGlobal.h>
#include <maya/MFnCamera.h>
#include <maya/MTemplateCommand.h>

// Statics
MTypeId lineManip::id( 0x81047 );

// Utility class for returning line points
class lineGeometry
{
public:
    static MPoint topPoint() {
        return MPoint( 1.0f, 1.0f, 0.0f );
    }
    static MPoint bottomPoint() {
        return MPoint( 1.0f, -1.0f, 0.0f );
    }
    static MPoint otherPoint() {
        return MPoint( 2.0f, -1.0f, 0.0f );
    }
};

//
// class implementation
//
lineManip::lineManip()
{
    // Setup the plane with a point on the
    // plane along with a normal
    MPoint pointOnPlane(lineGeometry::topPoint());
    // Normal = cross product of two vectors on the plane
    MVector normalToPlane = (MVector(lineGeometry::topPoint()) - MVector(lineGeometry::otherPoint())) ^ 
                    (MVector(lineGeometry::otherPoint()) - MVector(lineGeometry::bottomPoint()));
    // Necessary to normalize
    normalToPlane.normalize();
    // Plane defined by a point and a normal
    plane.setPlane( pointOnPlane, normalToPlane );
}

lineManip::~lineManip()
{
    // No-op
}

void lineManip::postConstructor()
{
    // Get the starting value of the pickable items
    glFirstHandle( lineName );
}

// virtual 
void    lineManip::preDrawUI( const M3dView &view )
{
    // Initial as draw manipulator in vp2
    fDrawManip = true;

    // Are we in the right view
    M3dView *viewPtr = const_cast<M3dView*>( &view );
    MDagPath dpath;
    viewPtr->getCamera(dpath);
    MFnCamera viewCamera(dpath);
    const char *nameBuffer = viewCamera.name().asChar();
    if ( 0 == nameBuffer )
        fDrawManip = false;
    if ( ( 0 == strstr(nameBuffer,"persp") ) && ( 0 == strstr(nameBuffer,"front") ) )
        fDrawManip = false;

    if ( !fDrawManip )
        return;

    fLineColorIndex = mainColor();
    fSelectedLineColorIndex = selectedColor();
    fLineStart = lineGeometry::topPoint() + MVector( mousePointGlName );
    fLineEnd   = lineGeometry::bottomPoint()   + MVector( mousePointGlName );
}

// virtual 
void    lineManip::drawUI(
    MHWRender::MUIDrawManager& drawManager,
    const MHWRender::MFrameContext& frameContext ) const
{
    if ( !fDrawManip )
        return;

    drawManager.beginDrawable(MHWRender::MUIDrawManager::kSelectable, lineName);
    setHandleColor(drawManager, lineName, fLineColorIndex);
    drawManager.line( fLineStart, fLineEnd );
    drawManager.endDrawable();

    drawManager.beginDrawable();
    drawManager.setColorIndex( fLineColorIndex );
    drawManager.text( fLineStart, MString("line manip"));
    drawManager.endDrawable();
}

// virtual 
MStatus lineManip::doPress( M3dView& view )
{
    // Reset the mousePoint information on
    // a new press
    mousePointGlName = MPoint::origin;
    updateDragInformation();
    return MS::kSuccess;
}

// virtual
MStatus lineManip::doDrag( M3dView& view )
{
    updateDragInformation();
    return MS::kSuccess;
}

// virtual
 MStatus lineManip::doRelease( M3dView& view )
{
    // Scale nodes on the selection list.
    // Simple implementation that does not
    // support undo.
    MSelectionList list;
    MGlobal::getActiveSelectionList( list );
    for ( MItSelectionList iter( list ); !iter.isDone(); iter.next() ) 
    {
        MObject node;
        MStatus status;
            iter.getDependNode( node );
        MFnTransform xform( node, &status );
        if ( MS::kSuccess == status )
        {
            double newScale[3];
            newScale[0] = mousePointGlName.x + 1;
            newScale[1] = mousePointGlName.y + 1;
            newScale[2] = mousePointGlName.z + 1;
            xform.setScale( newScale );
        }
    }
    return MS::kSuccess;
}

MStatus lineManip::updateDragInformation()
{
    // Find the mouse point in local space
    MPoint localMousePoint;
    MVector localMouseDirection;
    if ( MS::kFailure == mouseRay( localMousePoint, localMouseDirection) )
        return MS::kFailure;

    // Find the intersection of the mouse point with the
    // manip plane
    MPoint mouseIntersectionWithManipPlane;
    if ( ! plane.intersect( localMousePoint, localMouseDirection,   mouseIntersectionWithManipPlane ) )
        return MS::kFailure;

    mousePointGlName = mouseIntersectionWithManipPlane;

    MGLuint active = 0;
    if ( glActiveName( active ) )
    {
        float start[4],end[4];
        if ( active == lineName )
        {
            lineGeometry::topPoint().get(start);
            lineGeometry::bottomPoint().get(end);
        }

        if ( active != 0 )
        {
            lineMath line;
            // Find a vector on the plane
            MPoint a( start[0], start[1], start[2] );
            MPoint b( end[0], end[1], end[2] );
            MPoint vab = a - b;
            // Define line with a point and a vector on the plane
            line.setLine( start, vab );
            MPoint cpt;
            // Find the closest point so that we can get the
            // delta change of the mouse in local space
            if ( line.closestPoint( mousePointGlName, cpt ) )
            {
                mousePointGlName.x -= cpt.x;
                mousePointGlName.y -= cpt.y;
                mousePointGlName.z -= cpt.z;
            }
        }
    }
    return MS::kFailure;
}

//
// Template command that creates and deletes the manipulator
//

class lineManipCmd;
char cmdName[] = "lineManipCmd";
char nodeName[] = "simpleLineManip"; // lineManip already taken

class lineManipCmd : public MTemplateCreateNodeCommand<lineManipCmd,cmdName,nodeName>
{
public:
    //
    lineManipCmd()
    {}
};

static lineManipCmd _lineManipCmd;

//
// Static methods
//
void* lineManip::creator()
{
    return new lineManip();
}

MStatus lineManip::initialize()
{
    return MS::kSuccess;
}

//
//  Entry points
//

MStatus initializePlugin( MObject obj )
{ 
    MStatus   status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "2009", "Any");

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

    status = _lineManipCmd.registerCommand( obj );
    if (!status) 
    {
        status.perror("registerCommand");
        return status;
    }

    return status;
}

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

    status = plugin.deregisterNode( lineManip::id );
    if (!status) 
    {
        status.perror("deregisterNode");
        return status;
    }
    status = _lineManipCmd.deregisterCommand( obj );
    if (!status) 
    {
        status.perror("deregisterCommand");
        return status;
    }

    return status;
}