findTexturesPerPolygonCmd.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.
// ==========================================================================
//+

//
// Registers a new command called "findTexturesPerPolygon".
// Takes a selected mesh and outputs polygonal sets with file textures applied
// to a "color" attribute, and members of each set. The output is to stderr.
//

#include <maya/MIOStream.h>
#include <maya/MSimple.h>
#include <maya/MString.h>
#include <maya/MFnMesh.h>
#include <maya/MFnSet.h>
#include <maya/MItDependencyGraph.h>
#include <maya/MItMeshPolygon.h>
#include <maya/MSelectionList.h>
#include <maya/MGlobal.h>
#include <maya/MDagPath.h>
#include <maya/MObjectArray.h>
#include <maya/MPlug.h>

MObject findShader( MObject& setNode )
//
//  Description:
//      Find the shading node for the given shading group set node.
//
{
        MFnDependencyNode fnNode(setNode);
        MPlug shaderPlug = fnNode.findPlug("surfaceShader");
                        
        if (!shaderPlug.isNull()) {                     
                MPlugArray connectedPlugs;
                bool asSrc = false;
                bool asDst = true;
                shaderPlug.connectedTo( connectedPlugs, asDst, asSrc );

                if (connectedPlugs.length() != 1)
                        cerr << "Error getting shader\n";
                else 
                        return connectedPlugs[0].node();
        }                       
        
        return MObject::kNullObj;
}

DeclareSimpleCommand( findTexturesPerPolygon, PLUGIN_COMPANY, "3.0" );

MStatus findTexturesPerPolygon::doIt( const MArgList& )
//
//  Description:
//      Find the texture files that apply to the color of each polygon of
//      a selected shape if the shape has its polygons organized into sets.
//
{
    // Get the selection and choose the first path on the selection list.
    //
        MStatus status;
        MDagPath path;
        MObject cmp;
        MSelectionList slist;
        MGlobal::getActiveSelectionList(slist);
        slist.getDagPath(0, path, cmp);

        // Have to make the path include the shape below it so that
        // we can determine if the underlying shape node is instanced.
        // By default, dag paths only include transform nodes.
        //
        path.extendToShape();

        // If the shape is instanced then we need to determine which
        // instance this path refers to.
        //
        int instanceNum = 0;
        if (path.isInstanced())
                instanceNum = path.instanceNumber();

    // Get a list of all sets pertaining to the selected shape and the
    // members of those sets.
    //
        MFnMesh fnMesh(path);
        MObjectArray sets;
        MObjectArray comps;
        if (!fnMesh.getConnectedSetsAndMembers(instanceNum, sets, comps, true))
                cerr << "ERROR: MFnMesh::getConnectedSetsAndMembers\n";

        // Loop through all the sets.  If the set is a polygonal set, find the
    // shader attached to the and print out the texture file name for the
    // set along with the polygons in the set.
        //
        for ( unsigned i=0; i<sets.length(); i++ ) {
                MObject set = sets[i];
                MObject comp = comps[i];

                MFnSet fnSet( set, &status );
                if (status == MS::kFailure) {
            cerr << "ERROR: MFnSet::MFnSet\n";
            continue;
        }

        // Make sure the set is a polygonal set.  If not, continue.
                MItMeshPolygon piter(path, comp, &status);
                if ((status == MS::kFailure) || comp.isNull())
            continue;

                // Find the texture that is applied to this set.  First, get the
                // shading node connected to the set.  Then, if there is an input
                // attribute called "color", search upstream from it for a texture
                // file node.
        //
                MObject shaderNode = findShader(set);
                if (shaderNode == MObject::kNullObj)
                        continue;

                MPlug colorPlug = MFnDependencyNode(shaderNode).findPlug("color", &status);
                if (status == MS::kFailure)
                        continue;

                MItDependencyGraph dgIt(colorPlug, MFn::kFileTexture,
                                                   MItDependencyGraph::kUpstream, 
                                                   MItDependencyGraph::kBreadthFirst,
                                                   MItDependencyGraph::kNodeLevel, 
                                                   &status);

                if (status == MS::kFailure)
                        continue;
                
                dgIt.disablePruningOnFilter();

        // If no texture file node was found, just continue.
        //
                if (dgIt.isDone())
                        continue;
                  
        // Print out the texture node name and texture file that it references.
        //
                MObject textureNode = dgIt.thisNode();
        MPlug filenamePlug = MFnDependencyNode(textureNode).findPlug("fileTextureName");
        MString textureName;
        filenamePlug.getValue(textureName);
                cerr << "Set: " << fnSet.name() << endl;
        cerr << "Texture Node Name: " << MFnDependencyNode(textureNode).name() << endl;
                cerr << "Texture File Name: " << textureName.asChar() << endl;
        
        // Print out the set of polygons that are contained in the current set.
        //
                for ( ; !piter.isDone(); piter.next() )
                        cerr << "    poly component: " << piter.index() << endl;
        }

        return MS::kSuccess;
}