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

// DESCRIPTION:
//
// Produces the MEL command "findTexturesPerPolygon".
//
// This example is a variation of the "findFileTexturesCmd" example.
// When a file texture node is connected to the color attribute of a shader, the file name
// is extracted and printed along with the polygonal index. 
//
// To use this plug-in:
//  (1) Apply a shader that has a file texture node applied to the color attribute on a selected object.
//  (2) Execute the command "findTexturesPerPolygon". 
//

#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", true);
            
    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",  true,  &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.currentItem();
        MPlug filenamePlug = MFnDependencyNode(textureNode).findPlug("fileTextureName", true);
        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;
}