Programming With QuickTime Sprites

Creating the Movie, Sprite Track, and Media

Listing 1-6 shows a code fragment from the sample code QTWiredSprites.c . This sample code, which is available in Appendix C, illustrates how you can create a new movie file that calls a sample code function, AddSpriteTrackToMovie , which is responsible for creating a sprite track and adding it to the movie.

Listing 6 Creating a sprite track movie



 
// Create a QuickTime movie containing a wired sprites track.



OSErr QTWired_CreateWiredSpritesMovie (void)

{

    short                   myResRefNum = 0;

    Movie                   myMovie = NULL;

    Track                   myTrack;

    Media                   myMedia;

    StandardFileReply       myReply;

    QTAtomContainer         mySample = NULL;

    QTAtomContainer         myActions = NULL;

    QTAtomContainer         myBeginButton, myPrevButton, myNextButton, 

                                myEndButton;

    QTAtomContainer         myPenguinOne, myPenguinTwo, 

                                myPenguinOneOverride;

    QTAtomContainer         myBeginActionButton, myPrevActionButton, 

                                myNextActionButton, myEndActionButton;

    QTAtomContainer         myPenguinOneAction, myPenguinTwoAction;

    RGBColor                myKeyColor;

    Point                   myLocation;

    short                   isVisible, myLayer, myIndex, myResID, i, 

                                myDelta;

    Boolean                 hasActions;

    long                    myFlags = createMovieFileDeleteCurFile | 

                                createMovieFileDontCreateResFile;

    OSType                  myType = FOUR_CHAR_CODE('none');

    UInt32                  myFrequency;

    QTAtom                  myEventAtom;

    long                    myLoopingFlags;

    ModifierTrackGraphicsModeRecord     myGraphicsMode;

    OSErr                   myErr = noErr;



    // create a new movie file and set its controller type

    // ask the user for the name of the new movie file

    StandardPutFile("\pSprite movie file name:", "\pSprite.mov", 

                    &myReply);

    if (!myReply.sfGood)

        goto bail;



    // create a movie file for the destination movie

    myErr = CreateMovieFile(&myReply.sfFile, FOUR_CHAR_CODE('TVOD'), 0, 

                myFlags, &myResRefNum, &myMovie);

    if (myErr != noErr)

        goto bail;

    

    // select the "no controller" movie controller

    myType = EndianU32_NtoB(myType);

    SetUserDataItem(GetMovieUserData(myMovie), &myType, sizeof(myType), 

                        kUserDataMovieControllerType, 1);

The following code fragment from AddSpriteTrackToMovie ( Listing 1-7 ) creates a new track and new media, and creates an empty key frame sample. AddSpriteTrackToMovie then calls BeginMediaEdits ( Listing 1-9 ) to prepare to add samples to the track's media.

Listing 7 Creating a track and media



 
// create the sprite track and media

    

    myTrack = NewMovieTrack(myMovie, ((long)kSpriteTrackWidth << 16), 

                        ((long)kSpriteTrackHeight << 16), kNoVolume);

    myMedia = NewTrackMedia(myTrack, SpriteMediaType, 

                            kSpriteMediaTimeScale, NULL, 0);



    // create a new, empty key frame sample

    myErr = QTNewAtomContainer(&mySample);

    if (myErr != noErr)

        goto bail;



    myKeyColor.red = 0xffff;                        // white

    myKeyColor.green = 0xffff;

    myKeyColor.blue = 0xffff;