intersectCmd/intersectCmd.cpp

//-
// ==========================================================================
// Copyright 1995,2006,2020 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:
//
// Produces a proxy command "intersectCmd".
//
// This is an example of finding the intersection points on a mesh from a spotlight using the
// intersection acceleration methods in MFnMesh.
//
// To use the plug-in:
//  
//  (1) Create a spotlight and a poly plane (mesh).
//
//  (2) Orient the light to shine on the plane.
//
//  (3) Run the command as such: intersectCmd <spotLightName> <planeName>.
//      If there is an intersection, a small sphere will be created at the intersection point.
//
//  Use the following script to automatically display intersections on the mesh (assuming 
//  a spotlight and a mesh with the names used here exist):
//
//  global proc intersectExample()
//
//  {
//
//      intersectCmd spotLight1 pPlane1;
//      select -r spotLight1;
//
//  }
//
//  scriptJob -ac "spotLight1.tx" intersectExample;
//  scriptJob -ac "spotLight1.ty" intersectExample;
//  scriptJob -ac "spotLight1.tz" intersectExample;
//  scriptJob -ac "spotLight1.rx" intersectExample;
//  scriptJob -ac "spotLight1.ry" intersectExample;
//  scriptJob -ac "spotLight1.rz" intersectExample;
//

// MAYA HEADERS
#include <maya/MFnPlugin.h>
#include <maya/MDagPath.h>
#include <maya/MFnMesh.h>
#include <maya/MItSelectionList.h>
#include <maya/MItMeshPolygon.h>
#include <maya/MObject.h>
#include <maya/MSelectionList.h>
#include <maya/MArgList.h>
#include <maya/MFloatPoint.h>
#include <maya/MFnDependencyNode.h>
#include <maya/MFnSpotLight.h>
#include <maya/MFloatPointArray.h>
#include <maya/MPxCommand.h>
#include <maya/MDGModifier.h>
#include <maya/MFnDagNode.h>
#include <maya/MDagPath.h>
#include <maya/MGlobal.h>

#define MERR_CHK(stat,msg) if ( !stat ) { MGlobal::displayError(msg); } // cerr << msg << endl; }
// MAIN CLASS FOR THE INTERSECTCMD COMMAND:
class intersectCmd : public MPxCommand
{
    public:
        intersectCmd();
        ~intersectCmd() override;
        static void* creator();
        bool isUndoable() const override;
        
        MStatus doIt(const MArgList&) override;
        MStatus undoIt() override;
};

// CONSTRUCTOR:
intersectCmd::intersectCmd()
{
}

// DESTRUCTOR:
intersectCmd::~intersectCmd()
{
}

// FOR CREATING AN INSTANCE OF THIS COMMAND:
void* intersectCmd::creator()
{
   return new intersectCmd;
}

// MAKE THIS COMMAND NOT UNDOABLE:
bool intersectCmd::isUndoable() const
{
   return false;
}


MStatus intersectCmd::doIt(const MArgList& args)

// Description:
//      Determine if the ray from the spotlight intersects the mesh.
//      If it does, display the intersection points.

{
    MStatus stat = MStatus::kSuccess;

    if (args.length() != 2) 
    {
        MGlobal::displayError("Need 2 items!");
        return MStatus::kFailure;
    }

    MSelectionList activeList;
    int i;
    
    for ( i = 0; i < 2; i++)
    {
        MString strCurrSelection;
        stat = args.get(i, strCurrSelection);
        if (MStatus::kSuccess == stat) activeList.add(strCurrSelection);
    }

    MItSelectionList iter(activeList);
    MFnSpotLight fnLight;  
    MFnMesh fnMesh;
    MFnDagNode dagNod;
    MFnDependencyNode fnDN;

    float fX = 0;
    float fY = 0;
    float fZ = 0;

    for ( ; !iter.isDone(); iter.next() )
    {
        MObject tempObjectParent, tempObjectChild;
        iter.getDependNode(tempObjectParent);

        if (tempObjectParent.apiType() == MFn::kTransform)
        {
            dagNod.setObject(tempObjectParent);
            tempObjectChild = dagNod.child(0, &stat);
        }

        // check what type of object is selected
        if (tempObjectChild.apiType() == MFn::kSpotLight)
        {
            MDagPath pathToLight;
            MERR_CHK(MDagPath::getAPathTo(tempObjectParent, pathToLight), "Couldn't get a path to the spotlight");
            MERR_CHK(fnLight.setObject(pathToLight), "Failure on assigning light");
            
            stat = fnDN.setObject(tempObjectParent);

            MPlug pTempPlug = fnDN.findPlug("translateX", true, &stat);
            if (MStatus::kSuccess == stat)
            {
                pTempPlug.getValue(fX);
            }

            pTempPlug = fnDN.findPlug("translateY", true, &stat);
            if (MStatus::kSuccess == stat)
            {
                pTempPlug.getValue(fY);
            }

            pTempPlug = fnDN.findPlug("translateZ", true, &stat);
            if (MStatus::kSuccess == stat)
            {
                pTempPlug.getValue(fZ);
            }   
        }
        else if (tempObjectChild.apiType() == MFn::kMesh)
        {
            MDagPath pathToMesh;
            MERR_CHK(MDagPath::getAPathTo(tempObjectChild, pathToMesh), "Couldn't get a path to the spotlight");
            MERR_CHK(fnMesh.setObject(pathToMesh), "Failure on assigning light");   
        }
        else
        {
            MGlobal::displayError("Need a spotlight and a mesh");
            return MStatus::kFailure;
        }
    }

    MFloatPoint fpSource(fX, fY, fZ);
    MFloatVector fvRayDir = fnLight.lightDirection(0, MSpace::kWorld, &stat);
    MFloatPoint hitPoint;
    
    MMeshIsectAccelParams mmAccelParams = fnMesh.autoUniformGridParams();
    
    float fHitRayParam, fHitBary1, fHitBary2;
    int nHitFace, nHitTriangle;

    // a large positive number is used here for the maxParam parameter
    bool bAnyIntersection = fnMesh.anyIntersection(fpSource, fvRayDir, NULL, NULL, false,               MSpace::kWorld, (float)9999, false, &mmAccelParams, hitPoint, &fHitRayParam, &nHitFace, &nHitTriangle,      &fHitBary1, &fHitBary2, (float)1e-6, &stat);
    
    if (! bAnyIntersection) 
    {
        MGlobal::displayInfo("There were no intersection points detected");
        return stat;
    }

    MFloatPointArray hitPoints;
    MFloatArray faHitRayParams;
    MIntArray iaHitFaces;
    MIntArray iaHitTriangles;
    MFloatArray faHitBary1;
    MFloatArray faHitBary2;

    bool bAllIntersections = fnMesh.allIntersections(fpSource, fvRayDir, NULL, NULL, false, MSpace::kWorld, 9999, false, NULL, false, hitPoints, &faHitRayParams, &iaHitFaces, &iaHitTriangles, &faHitBary1, &faHitBary2, 0.000001f, &stat);
    
    if (! bAllIntersections)
    {
        MGlobal::displayInfo("Error getting all intersections");
        return stat;
    }
    
    // check how many intersections are found
    unsigned int nNumberHitPoints = hitPoints.length();

    if (! nNumberHitPoints)
    {
        MGlobal::displayInfo("No hit points detected");
        return MStatus::kSuccess;
    }

    // Intersection exists; display intersections as spheres
    MString strCommandString = "string $strBall[] = `polySphere -r 0.5`;";
    strCommandString += "$strBallName = $strBall[0];";

    float x = 0;
    float y = 0;
    float z = 0;

    for (i = 0; i < (int)nNumberHitPoints; i++)
    {
        // get the points
        x = hitPoints[i][0];
        y = hitPoints[i][1];
        z = hitPoints[i][2];

        // execute some MEL to create a small sphere
        strCommandString += "setAttr ($strBallName + \".tx\") ";
        strCommandString += x;
        strCommandString += ";";

        strCommandString += "setAttr ($strBallName + \".ty\") ";
        strCommandString += y;
        strCommandString += ";";

        strCommandString += "setAttr ($strBallName + \".tz\") ";
        strCommandString += z;
        strCommandString += ";";

        MGlobal::executeCommand(strCommandString);
    }

    return stat;
}

// UNDO THE COMMAND
MStatus intersectCmd::undoIt()
{
    MStatus status;
    // undo not implemented
    return status;
}

// INITIALIZE THE PLUGIN:
MStatus initializePlugin(MObject obj)
{
    MStatus status;
    MFnPlugin plugin(obj, PLUGIN_COMPANY, "6.5", "Any");

    status = plugin.registerCommand("intersectCmd", intersectCmd::creator);

    return status;
}

// UNINITIALIZE THE PLUGIN:
MStatus uninitializePlugin(MObject obj)
{
    MStatus status;
    MFnPlugin plugin(obj);

    plugin.deregisterCommand("intersectCmd");

    return status;
}