Programming With QuickTime VR

Hot Spot Information Atom

The hot spot information atom contains general information about a hot spot. Its atom type is kQTVRHotSpotInfoAtomType ('hsin' ). Every hot spot atom should have a hot spot information atom as a child.

The structure of a hot spot information atom is defined by the VRHotSpotInfoAtom data type:



 
typedef struct VRHotSpotInfoAtom {

    UInt16                              majorVersion;

    UInt16                              minorVersion;

    OSType                              hotSpotType;

    QTAtomID                            nameAtomID;

    QTAtomID                            commentAtomID;

    SInt32                              cursorID[3];

    Float32                             bestPan;

    Float32                             bestTilt;

    Float32                             bestFOV;

    FloatPoint                          bestViewCenter;

    Rect                                hotSpotRect;

    UInt32                              flags;

    UInt32                              reserved1;

    UInt32                              reserved2;

} VRHotSpotInfoAtom, *VRHotSpotInfoAtomPtr;

majorVersion: The major version number of the file format.
minorVersion: The minor version number of the file format.
hotSpotType: The hot spot type. This type specifies which other information atoms--if any--are siblings to this one. QuickTime VR recognizes three types: kQTVRHotSpotLinkType , kQTVRHotSpotURLType , and kQTVRHotSpotUndefinedType .
nameAtomID: The ID of the string atom that contains the name of the hot spot. This atom should be a sibling of the hot spot information atom. This string is displayed in the QuickTime VR controller bar when the mouse is moved over the hot spot.
commentAtomID: The ID of the string atom that contains a comment for the hot spot. This atom should be a sibling of the hot spot information atom. The value of this field is 0 if no comment string atom exists.
cursorID: An array of three IDs for custom hot spot cursors (that is, cursors that override the default hot spot cursors provided by QuickTime VR). The first ID (cursorID[0] ) specifies the cursor that is displayed when it is in the hot spot. The second ID (cursorID[1] ) specifies the cursor that is displayed when it is in the hot spot and the mouse button is down. The third ID (cursorID[2] ) specifies the cursor that is displayed when it is in the hot spot and the mouse button is released. To retain the default cursor for any of these operations, set the corresponding cursor ID to 0. Custom cursors should be stored in the VR world atom container, as described in "VR World Atom Container" .
bestPan: The best pan angle for viewing this hot spot.
bestTilt: The best tilt angle for viewing this hot spot.
bestFOV: The best field of view for viewing this hot spot.
bestViewCenter: The best view center for viewing this hot spot; applies only to object nodes.
hotSpotRect: The boundary box for this hot spot, specified as the number of pixels in full panoramic space. This field is valid only for panoramic nodes.
flags: A set of hot spot flags. Currently, this field is unused.
reserved1: Reserved. This field must be 0.
reserved2: Reserved. This field must be 0.

In QuickTime VR movie files, all angular values are stored as 32-bit floating-point values that specify degrees. In addition, all floating-point values conform to the IEEE Standard 754 for binary floating-point arithmetic, in big-endian format.