polyWriter.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.
// ==========================================================================
//+

//
//

//polyWriter.cpp

//General Includes
//
#include <maya/MIOStream.h>
#include <maya/MGlobal.h>
#include <maya/MFnSet.h>
#include <maya/MDagPath.h>
#include <maya/MItDependencyGraph.h>
#include <maya/MPlug.h>

//Iterator Includes
//
#include <maya/MItMeshPolygon.h>

//Header File
//
#include "polyWriter.h"


polyWriter::polyWriter(MDagPath dagPath, MStatus& status)
//Summary:      Constructor - creates the MDagPath and MFnMesh objects necessary
//                      for extracting the data
//Args   :      dagPath - the dagPath where the mesh is located=
//                      status - will be set to MStatus::kSuccess if the creation of the 
//                      MFnMesh is successful; MStatus::kFailure otherwise
{
        fDagPath = new MDagPath(dagPath);
        fMesh = new MFnMesh(*fDagPath, &status);
}


polyWriter::~polyWriter()
//Summary:      Destructor - deletes all constructor created objects
{
        if (NULL != fDagPath) delete fDagPath;
        if (NULL != fMesh) delete fMesh;
}

MStatus polyWriter::extractGeometry() 
//Summary:      extracts the main geometry (vertices, vertex colours, vertex normals) 
//                      of this polygonal mesh.  
//Returns:  MStatus::kSuccess if the method succeeds
//                      MStatus::kFailure if the method fails
{

        if (MStatus::kFailure == fMesh->getPoints(fVertexArray, MSpace::kWorld)) {
                MGlobal::displayError("MFnMesh::getPoints"); 
                return MStatus::kFailure;
        }

        if (MStatus::kFailure == fMesh->getFaceVertexColors(fColorArray)) {
                MGlobal::displayError("MFnMesh::getFaceVertexColors"); 
                return MStatus::kFailure;
        }

        if (MStatus::kFailure == fMesh->getNormals(fNormalArray, MSpace::kWorld)) {
                MGlobal::displayError("MFnMesh::getNormals"); 
                return MStatus::kFailure;
        }
        if (MStatus::kFailure == fMesh->getCurrentUVSetName(fCurrentUVSetName)) {
                MGlobal::displayError("MFnMesh::getCurrentUVSetName"); 
                return MStatus::kFailure;
        }

        if (MStatus::kFailure == fMesh->getTangents(fTangentArray, MSpace::kWorld, &fCurrentUVSetName)) {
                MGlobal::displayError("MFnMesh::getTangents"); 
                return MStatus::kFailure;
        }

        if (MStatus::kFailure == fMesh->getBinormals(fBinormalArray, MSpace::kWorld, &fCurrentUVSetName)) {
                MGlobal::displayError("MFnMesh::getBinormals"); 
                return MStatus::kFailure;
        }

        //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.
        //
        fDagPath->extendToShape();

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

        //Get the connected sets and members - these will be used to determine texturing of different
        //faces
        //
        if (!fMesh->getConnectedSetsAndMembers(instanceNum, fPolygonSets, fPolygonComponents, true)) {
                MGlobal::displayError("MFnMesh::getConnectedSetsAndMembers"); 
                return MStatus::kFailure;
        }

        return MStatus::kSuccess;
}


void polyWriter::outputTabs(ostream& os, unsigned int tabCount) 
//Summary:      outputs tab spacing
//Args   :      os - an output stream to write to
//                      tabCount - the number of tabs to print
//Returns:  MStatus::kSuccess if the method succeeds
//                      MStatus::kFailure if the method fails
{
        unsigned int i;
        for (i = 0; i < tabCount; i++) {
                os << "\t";
        }
}



MObject polyWriter::findShader(const MObject& setNode) 
//Summary:      finds the shading node for the given shading group set node
//Args   :      setNode - the shading group set node
//Returns:  the shader node for setNode if found;
//                      MObject::kNullObj otherwise
{

        MFnDependencyNode fnNode(setNode);
        MPlug shaderPlug = fnNode.findPlug("surfaceShader");
                        
        if (!shaderPlug.isNull()) {                     
                MPlugArray connectedPlugs;

                //get all the plugs that are connected as the destination of this 
                //surfaceShader plug so we can find the surface shaderNode
                //
                MStatus status;
                shaderPlug.connectedTo(connectedPlugs, true, false, &status);
                if (MStatus::kFailure == status) {
                        MGlobal::displayError("MPlug::connectedTo");
                        return MObject::kNullObj;
                }

                if (1 != connectedPlugs.length()) {
                        MGlobal::displayError("Error getting shader for: " + fMesh->partialPathName());
                } else {
                        return connectedPlugs[0].node();
                }
        }
        
        return MObject::kNullObj;
}




MStatus polyWriter::outputSets(ostream& os)
//Summary:      outputs this mesh's sets and each sets face components, and any 
//                      associated texture
//Args   :      os - an output stream to write to
//Returns:      MStatus::kSuccess if set information was outputted
//                      MStatus::kFailure otherwise
{
        MStatus status;

        //if there is more than one set, the last set simply consists of all 
        //polygons, so we won't include it
        //
        unsigned int setCount = fPolygonSets.length();
        if (setCount > 1) {
                setCount--;
        }

        MIntArray faces;

        unsigned int i;
        for (i = 0; i < setCount; i++ ) {
                MObject set = fPolygonSets[i];
                MObject comp = fPolygonComponents[i];
                MFnSet fnSet(set, &status);
                if (MS::kFailure == status) {
                        MGlobal::displayError("MFnSet::MFnSet");
            continue;
        }

        //Make sure the set is a polygonal set.  If not, continue.
                MItMeshPolygon itMeshPolygon(*fDagPath, comp, &status);

                if ((MS::kFailure == status)) {
                        MGlobal::displayError("MItMeshPolygon::MItMeshPolygon");
            continue;
                }

                //add the current set's face indices to the faces array
                //
                faces.setLength(itMeshPolygon.count());

                unsigned int j = 0;
                for (itMeshPolygon.reset(); !itMeshPolygon.isDone(); itMeshPolygon.next()) {
                        faces[j++] = itMeshPolygon.index();
                }

                //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 (MObject::kNullObj == shaderNode) {
                        continue;
                }

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

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

                if (MS::kFailure == status) {
                        MGlobal::displayError("MItDependencyGraph::MItDependencyGraph");
                        continue;
                }

                //disable automatic pruning so that we can locate a specific plug 
                itDG.disablePruningOnFilter();

                //If no texture file node was found, pass in an empty string as the texture filename 
                //so that color information is outputted instead
                //
                MString textureName("");
                if (itDG.isDone()) {
                        if (MStatus::kFailure == outputSingleSet(os, MString(fnSet.name()), faces, textureName)) {
                                return MStatus::kFailure;
                        }
                //otherwise retrieve the filename and pass it in to output texture information
                //
                } else {
                        MObject textureNode = itDG.thisNode();
                        MPlug filenamePlug = MFnDependencyNode(textureNode).findPlug("fileTextureName");
                        filenamePlug.getValue(textureName);
                        if (MStatus::kFailure == outputSingleSet(os, MString(fnSet.name()), faces, textureName)) {
                                return MStatus::kFailure;
                        }

                }
        }
        return MStatus::kSuccess;
}