Implementing your own 3D parser

3

Steps to make an extension being recognized by the SDK

• Implement a C3DParser (Read and / or Save and / or Update methods)
• Implement a function that will be called for creating / destroying the parser object
• Register the extension using fileRegisterFile

Please have a look at the 3DCustomFormat in the SDK samples.

Make the scene being prepared after import or before export

C3DParser usually defines some needed flags for reading in the C3DParser::LoadDefaultOptions implementation.
C3DParser::SaveDefaultOptions defines some needed flags for writing.

This method are optional. In this case default import / export processing occurs.

Here are some example of implementation:

void CExampleParser::LoadDefaultOptions(CSceneImportOptions& options) const
{
    options.neededflags = SCENE_IMPORT_CLEAN_GROUPS|SCENE_IMPORT_CONCATENATE;
    options.targetunit = UNIT_M;
}
 
void CExampleParser::SaveDefaultOptions(CSceneExportOptions& options) const
{
    options.swapmode = SWAP_YZ; // Swap Y & Z coordinate before export
    options.neededflags = SCENE_EXPORT_TRIANGULATE | SCENE_EXPORT_GLOBAL_COORDINATES | SCENE_EXPORT_CONVERT_TO_STANDARD_MATERIALS;
}

Implement Read or Save method

Implementation depends on your files. If the process fails, properly inform the C3DIo about what occurs.

Here are some example of read / write process, using the C3DScene::Serialize mechanism.

#define CUSTOM_3D_STRING MAKE_CUSTOM_ID('C', 'S', 'S', 'T')
#define CUSTOM_3D_INT MAKE_CUSTOM_ID('C', 'S', 'I', 'T')
 
C3DScene *C3DCustomFormat::Read(const CXString& filename, CSceneImportOptions& options)
{
    IoFile file(IsSilentMode(), IOFILE_MEMORY_FILE);
    if (!file.OpenFile(filename, true))
    {
        io->SetIoError(IO_FILE_CANT_OPEN_FILE, &options, IoLogInfo::LOG_ERROR);
        file.CloseFile();
        return NULL;
    }
 
    // You might exposes some specific controls for the caller. Here is the way to access to your specific data
    unsigned int value;
    CXString string;
    options.GetParserOptions().GetUInt(CUSTOM_3D_INT, value, 0);
    options.GetParserOptions().GetString(CUSTOM_3D_STRING, string, CXString());
 
    ioscene = xNew(C3DScene);
 
    CXArchive ar(file.GetCFile(), CXArchive::load);
    ioscene->Serialize(ar);
    ar.Close();
 
    file.CloseFile();
 
    return ioscene;
}
 
bool C3DCustomFormat::Save(const CXString& filename, C3DScene *userScene, CSceneExportOptions& options)
{
    IoFile iofile(IsSilentMode(), IOFILE_MEMORY_FILE);
    if (!iofile.OpenFile(filename, false))
    {
        io->SetIoError(IO_FILE_CANT_OPEN_FILE, &options, IoLogInfo::LOG_ERROR);
        return false;
    }
 
    userScene->SetFilename(CXString());
 
    CXArchive ar(iofile.GetCFile(), CXArchive::store);
    userScene->Serialize(ar);
    ar.Close();
 
    iofile.CloseFile();
 
    return true;
}

Implement a function to initialize / destroy the parser on request

When C3DIo recognized your format extension, it will ask you to create your C3DParser object and once finished to destroy it.

bool Init3DParser(IoPluginMode mode, void *data)
{
    switch (mode)
    {
    case IO_INIT_PLUGIN:
    {
    }
 
    case IO_GET_PARSER:
    {
        IOGetParserInfo *initParserInfo = (IOGetParserInfo *)data;
        switch (initParserInfo->fileclass)
        {
        case CUSTOM_3D_FILE:
            initParserInfo->parser = xNewParams(C3DCustomFormat, *(initParserInfo->io));
            break;
        }
        break;
    }
    }
 
    return TRUE;
}

Register your parser and extension

You have to inform the SDK that a new extension is recognized. You have to give your extension a file class and give some information about what the parser does.

CFileExt ext;
ext.description = "My custom 3D files"; // The parser name
ext.ext = ".mesh1|.mesh2"; // your 3d parser extensions
ext.fileclass = MAKE_CUSTOM_ID('C', 'S', 'T', 'M');
ext.properties = IMPORT_FILE | EXPORT_FILE | OBJECT_FILE | COMMON_EXTENSION_FILE | LOAD_HAS_DIALOG;
ext.iocallback = Init3DParser;
ext.loader = CALLBACK_PARSER; // Means that Init3DParser will be called when loading...
ext.saver = CALLBACK_PARSER; // ... and writing
 
fileRegisterFile(ext);