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# lassoTool.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.
    // ==========================================================================
    //+

    //
    // Lasso selection within a user defined context.
    //

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

    #include <maya/MFnPlugin.h>
    #include <maya/MString.h>
    #include <maya/MGlobal.h>
    #include <maya/M3dView.h>
    #include <maya/MDagPath.h>

    #include <maya/MItSelectionList.h>

    #include <maya/MPxContextCommand.h>
    #include <maya/MPxContext.h>
    #include <maya/MCursor.h>
    #include <maya/MEvent.h>

    #if defined(OSMac_MachO_)
    #include <OpenGL/gl.h>
    #include <OpenGL/glu.h>
    #else
    #include <GL/gl.h>
    #include <GL/glu.h>
    #endif

    #include <maya/MPoint.h>
    #include <maya/MPointArray.h>
    #include <maya/MItCurveCV.h>
    #include <maya/MItSurfaceCV.h>
    #include <maya/MItMeshVertex.h>
    #include <maya/MItMeshEdge.h>
    #include <maya/MItMeshPolygon.h>

    #ifdef _WIN32
    LPCSTR lassoToolCursor = "lassoToolCursor.cur";
    #else
    #include <lassoToolCursor.h>
    #include <lassoToolCursorMask.h>

    #define lassoToolCursor_x_hot 1
    #define lassoToolCursor_y_hot 16
    #endif

    class coord {
    public:
        short h;
        short v;
    };

    extern "C" int xycompare( coord *p1, coord *p2 );
    int xycompare( coord *p1, coord *p2 )
    {
        if ( p1->v > p2->v )
            return 1;
        if ( p2->v > p1->v )
            return -1;
        if ( p1->h > p2->h )
            return 1;
        if ( p2->h > p1->h )
            return -1;

        return 0;
    }

    // The user Context

    const int initialSize       = 1024;
    const int increment         =  256;
    const char helpString[]     = "drag mouse to select points by encircling";

    class lassoTool : public MPxContext
    {
    public:
                        lassoTool();
        virtual         ~lassoTool();
        void*           creator();

        virtual void    toolOnSetup( MEvent & event );
        virtual MStatus doPress( MEvent & event );
        virtual MStatus doDrag( MEvent & event );
        virtual MStatus doRelease( MEvent & event );

    private:
        void                    append_lasso( short x, short y );
        void                    draw_lasso();
        bool                    point_in_lasso( coord pt );

        bool                    firstDraw;
        coord                   min;
        coord                   max;
        unsigned                maxSize;
        unsigned                num_points;
        coord*                  lasso;
        MGlobal::ListAdjustment listAdjustment;
        M3dView                 view;
        MCursor                 lassoCursor;

    };

    lassoTool::lassoTool()
        : maxSize(0)
        , num_points(0)
        , lasso(NULL)
    #ifdef _WIN32
        , lassoCursor(lassoToolCursor)
    #else
        , lassoCursor(lassoToolCursor_width,
                  lassoToolCursor_height,
                  lassoToolCursor_x_hot,
                  lassoToolCursor_y_hot,
                  lassoToolCursor_bits,
                  lassoToolCursorMask_bits)
    #endif
    {
        setTitleString ( "Lasso Pick" );

        // set the initial state of the cursor
        setCursor(lassoCursor);

        // Tell the context which XPM to use so the tool can properly
        // be a candidate for the 6th position on the mini-bar.
        setImage("lassoTool.xpm", MPxContext::kImage1 );
    }

    lassoTool::~lassoTool() {}

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

    void lassoTool::toolOnSetup ( MEvent & )
    {
        setHelpString( helpString );
    }

    MStatus lassoTool::doPress( MEvent & event )
    // Set up for overlay drawing, and remember our starting point
    {
        // Figure out which modifier keys were pressed, and set up the
        // listAdjustment parameter to reflect what to do with the selected points.
        if (event.isModifierShift() || event.isModifierControl() ) {
            if ( event.isModifierShift() ) {
                if ( event.isModifierControl() ) {
                    // both shift and control pressed, merge new selections
                    listAdjustment = MGlobal::kAddToList;
                } else {
                    // shift only, xor new selections with previous ones
                    listAdjustment = MGlobal::kXORWithList;
                }
            } else if ( event.isModifierControl() ) {
                // control only, remove new selections from the previous list
                listAdjustment = MGlobal::kRemoveFromList;
            }
        } else {
            listAdjustment = MGlobal::kReplaceList;
        }

        // Get the active 3D view.
        //
        view = M3dView::active3dView();

        // Create an array to hold the lasso points. Assume no mem failures
        maxSize = initialSize;
        lasso = (coord*) malloc (sizeof(coord) * maxSize);

        coord start;
        event.getPosition( start.h, start.v );
        num_points = 1;
        lasso[0] = min = max = start;

        firstDraw = true;

        return MS::kSuccess;
    }

    MStatus lassoTool::doDrag( MEvent & event )
    // Add to the growing lasso
    {
        view.beginXorDrawing(true, true, 1.0f, M3dView::kStippleDashed);

        if (!firstDraw) {
            //  Redraw the old lasso to clear it.
            draw_lasso();
        } else {
            firstDraw = false;
        }

        coord currentPos;
        event.getPosition( currentPos.h, currentPos.v );
        append_lasso( currentPos.h, currentPos.v );

        //  Draw the new lasso.
        draw_lasso();

        view.endXorDrawing();

        return MS::kSuccess;
    }

    MStatus lassoTool::doRelease( MEvent & /*event*/ )
    // Selects objects within the lasso
    {
        MStatus                         stat;
        MSelectionList                  incomingList, boundingBoxList, newList;

        if (!firstDraw) {
            // Redraw the lasso to clear it.
            view.beginXorDrawing(true, true, 1.0f, M3dView::kStippleDashed);
            draw_lasso();
            view.endXorDrawing();
        }

        // We have a non-zero sized lasso.  Close the lasso, and sort
        // all the points on it.
        append_lasso(lasso[0].h, lasso[0].v);
        qsort( &(lasso[0]), num_points, sizeof( coord  ),
            (int (*)(const void *, const void *))xycompare);

        // Save the state of the current selections.  The "selectFromSceen"
        // below will alter the active list, and we have to be able to put
        // it back.
        MGlobal::getActiveSelectionList(incomingList);

        // As a first approximation to the lasso, select all components with
        // the bounding box that just contains the lasso.
        MGlobal::selectFromScreen( min.h, min.v, max.h, max.v,
                                   MGlobal::kReplaceList );

        // Get the list of selected items from within the bounding box
        // and create a iterator for them.
        MGlobal::getActiveSelectionList(boundingBoxList);

        // Restore the active selection list to what it was before we
        // the "selectFromScreen"
        MGlobal::setActiveSelectionList(incomingList, MGlobal::kReplaceList);

        // Iterate over the objects within the bounding box, extract the
        // ones that are within the lasso, and add those to newList.
        MItSelectionList iter(boundingBoxList);
        newList.clear();

        bool    foundEntireObjects = false;
        bool    foundComponents = false;

        for ( ; !iter.isDone(); iter.next() ) {
            MDagPath    dagPath;
            MObject     component;
            MPoint      point;
            coord       pt;
            MObject     singleComponent;

            iter.getDagPath( dagPath, component );

            if (component.isNull()) {
                foundEntireObjects = true;
                continue; // not a component
            }

            foundComponents = true;

            switch (component.apiType()) {
            case MFn::kCurveCVComponent:
                {
                    MItCurveCV curveCVIter( dagPath, component, &stat );
                    for ( ; !curveCVIter.isDone(); curveCVIter.next() ) {
                        point = curveCVIter.position(MSpace::kWorld, &stat );
                        view.worldToView( point, pt.h, pt.v, &stat );
                        if (!stat) {
                            stat.perror("Could not get position");
                            continue;
                        }
                        if ( point_in_lasso( pt ) ) {
                            singleComponent = curveCVIter.cv();
                            newList.add (dagPath, singleComponent);
                        }
                    }
                    break;
                }

            case MFn::kSurfaceCVComponent:
                {
                    MItSurfaceCV surfCVIter( dagPath, component, true, &stat );
                    for ( ; !surfCVIter.isDone(); surfCVIter.next() ) {
                        point = surfCVIter.position(MSpace::kWorld, &stat );
                        view.worldToView( point, pt.h, pt.v, &stat );
                        if (!stat) {
                            stat.perror("Could not get position");
                            continue;
                        }
                        if ( point_in_lasso( pt ) ) {
                            singleComponent = surfCVIter.cv();
                            newList.add (dagPath, singleComponent);
                        }
                    }
                    break;
                }

            case MFn::kMeshVertComponent:
                {
                    MItMeshVertex vertexIter( dagPath, component, &stat );
                    for ( ; !vertexIter.isDone(); vertexIter.next() ) {
                        point = vertexIter.position(MSpace::kWorld, &stat );
                        view.worldToView( point, pt.h, pt.v, &stat );
                        if (!stat) {
                            stat.perror("Could not get position");
                            continue;
                        }
                        if ( point_in_lasso( pt ) ) {
                            singleComponent = vertexIter.vertex();
                            newList.add (dagPath, singleComponent);
                        }
                    }
                    break;
                }

            case MFn::kMeshEdgeComponent:
                {
                    MItMeshEdge edgeIter( dagPath, component, &stat );
                    for ( ; !edgeIter.isDone(); edgeIter.next() ) {
                        point = edgeIter.center(MSpace::kWorld, &stat );
                        view.worldToView( point, pt.h, pt.v, &stat );
                        if (!stat) {
                            stat.perror("Could not get position");
                            continue;
                        }
                        if ( point_in_lasso( pt ) ) {
                            singleComponent = edgeIter.edge();
                            newList.add (dagPath, singleComponent);
                        }
                    }
                    break;
                }

            case MFn::kMeshPolygonComponent:
                {
                    MItMeshPolygon polygonIter( dagPath, component, &stat );
                    for ( ; !polygonIter.isDone(); polygonIter.next() ) {
                        point = polygonIter.center(MSpace::kWorld, &stat );
                        view.worldToView( point, pt.h, pt.v, &stat );
                        if (!stat) {
                            stat.perror("Could not get position");
                            continue;
                        }
                        if ( point_in_lasso( pt ) ) {
                            singleComponent = polygonIter.polygon();
                            newList.add (dagPath, singleComponent);
                        }
                    }
                    break;
                }

            default:
    #ifdef DEBUG
                cerr << "Selected unsupported type: (" << component.apiType()
                     << "): " << component.apiTypeStr() << endl;
    #endif /* DEBUG */
                continue;
            }
        }

        // Warn user if zie is trying to select objects rather than components.
        if (foundEntireObjects && !foundComponents) {
            MGlobal::displayWarning("lassoTool can only select components, not entire objects.");
        }

        // Update the selection list as indicated by the modifier keys.
        MGlobal::selectCommand(newList, listAdjustment);

        // Free the memory that held our lasso points.
        free(lasso);
        lasso = (coord*) 0;
        maxSize = 0;
        num_points = 0;

        return MS::kSuccess;
    }

    void lassoTool::append_lasso( short x, short y )
    {
        int     cy, iy, ix, ydif, yinc, i;
        float   fx, xinc;

        iy = (int)lasso[num_points-1].v;
        ix = (int)lasso[num_points-1].h;
        ydif = abs( y - iy );
        if ( ydif == 0 )
            return;

        // Keep track of smallest rectangular area of the screen that
        // completely contains the lasso.
        if ( min.h > x )
            min.h = x;
        if ( max.h < x )
            max.h = x;
        if ( min.v > y )
            min.v = y;
        if ( max.v < y )
            max.v = y;

        if ( ((int)y - iy ) < 0 )
            yinc = -1;
        else
            yinc = 1;

        xinc = (float)((int)x - ix)/(float)ydif;
        fx = (float)ix + xinc;
        cy = iy + yinc;
        for ( i = 0; i < ydif; i++ ) {

            if ( num_points >= maxSize ) {
                // Make the array of lasso points bigger
                maxSize += increment;

                // If realloc() fails, it returns NULL but keeps the old block
                // of memory around, so let's not overwrite the contents of
                // 'lasso' until we know that realloc() worked.
                coord* newLasso = (coord*) realloc (lasso, sizeof(coord) * maxSize);
                if (newLasso == NULL) return;

                lasso = newLasso;
            }

            lasso[num_points].h = (short) fx;
            lasso[num_points].v = (short) cy;
            fx += xinc;
            cy += yinc;
            num_points++;
        }

        return;
    }

    void lassoTool::draw_lasso()
    {
        glBegin( GL_LINE_LOOP );
        for ( unsigned i = 0; i < num_points ; i++ ){
            glVertex2i( lasso[i].h, lasso[i].v );
        }
        glEnd();
    }

    bool lassoTool::point_in_lasso( coord pt )
    {
        unsigned i, sides;

        for ( i = 0; i < num_points; i++ ) {
            if ( lasso[i].v == pt.v ) {
                while ( (lasso[i].v == pt.v ) && (lasso[i].h < pt.h) )
                    i++;
                if ( lasso[i].v != pt.v )
                    return( false );
                sides = 0;
                i++;
                while ( lasso[i].v == pt.v  ) {
                    i++;
                    sides++;
                }
                if ( sides % 2 )
                    return( false );
                else
                    return( true );
            }
        }
        return( false );
    }

    // Command to create contexts

    class lassoContextCmd : public MPxContextCommand
    {
    public:
                            lassoContextCmd() {};
        virtual MPxContext* makeObj();
        static void*        creator();
    };

    MPxContext* lassoContextCmd::makeObj()
    {
        return new lassoTool;
    }

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

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

        status = plugin.registerContextCommand( "lassoToolContext",
                                                lassoContextCmd::creator );

        if (!status) {
            status.perror("registerContextCommand");
            return status;
        }

        // set the mel scripts to be run when the plugin is loaded / unloaded
        status = plugin.registerUI("lassoToolCreateUI", "lassoToolDeleteUI");
        if (!status) {
            status.perror("registerUIScripts");
            return status;
        }

        return status;
    }

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

        status = plugin.deregisterContextCommand( "lassoToolContext" );

        return status;
    }