ClippingPolygonCollection

new Ditap.ClippingPolygonCollection(options)

Specifies a set of clipping polygons. Clipping polygons selectively disable rendering in a region inside or outside the specified list of ClippingPolygon objects for a single glTF model, 3D Tileset, or the globe. Clipping Polygons are only supported in WebGL 2 contexts.
Name Type Description
options object optional Object with the following properties:
Name Type Default Description
polygons Array.<ClippingPolygon> [] optional An array of ClippingPolygon objects used to selectively disable rendering on the inside of each polygon.
enabled boolean true optional Determines whether the clipping polygons are active.
inverse boolean false optional If true, a region will be clipped if it is outside of every polygon in the collection. Otherwise, a region will only be clipped if it is on the inside of any polygon.
Example:
const positions = Ditap.Cartesian3.fromRadiansArray([
    -1.3194369277314022,
    0.6988062530900625,
    -1.31941,
    0.69879,
    -1.3193955980204217,
    0.6988091578771254,
    -1.3193931220959367,
    0.698743632490865,
    -1.3194358224045408,
    0.6987471965556998,
]);

const polygon = new Ditap.ClippingPolygon({
    positions: positions
});

const polygons = new Ditap.ClippingPolygonCollection({
   polygons: [ polygon ]
});

Members

readonly length : number

Returns the number of polygons in this collection. This is commonly used with ClippingPolygonCollection#get to iterate over all the polygons in the collection.

polygonAdded : Event

An event triggered when a new clipping polygon is added to the collection. Event handlers are passed the new polygon and the index at which it was added.
Default Value: Event()

polygonRemoved : Event

An event triggered when a new clipping polygon is removed from the collection. Event handlers are passed the new polygon and the index from which it was removed.
Default Value: Event()

Methods

static Ditap.ClippingPolygonCollection.isSupported(scene) → boolean

Function for checking if the context will allow clipping polygons, which require floating point textures.
Name Type Description
scene Scene | object The scene that will contain clipped objects and clipping textures.
Returns:
true if the context supports clipping polygons.

add(polygon) → ClippingPolygon

Adds the specified ClippingPolygon to the collection to be used to selectively disable rendering on the inside of each polygon. Use ClippingPolygonCollection#unionClippingRegions to modify how modify the clipping behavior of multiple polygons.
Name Type Description
polygon ClippingPolygon The ClippingPolygon to add to the collection.
Returns:
The added ClippingPolygon.
Example:
const polygons = new Ditap.ClippingPolygonCollection();

const positions = Ditap.Cartesian3.fromRadiansArray([
    -1.3194369277314022,
    0.6988062530900625,
    -1.31941,
    0.69879,
    -1.3193955980204217,
    0.6988091578771254,
    -1.3193931220959367,
    0.698743632490865,
    -1.3194358224045408,
    0.6987471965556998,
]);

polygons.add(new Ditap.ClippingPolygon({
    positions: positions
}));
See:

contains(polygon) → boolean

Checks whether this collection contains a ClippingPolygon equal to the given ClippingPolygon.
Name Type Description
polygon ClippingPolygon The ClippingPolygon to check for.
Returns:
true if this collection contains the ClippingPolygon, false otherwise.
See:

destroy()

Destroys the WebGL resources held by this object. Destroying an object allows for deterministic release of WebGL resources, instead of relying on the garbage collector to destroy this object.

Once an object is destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception. Therefore, assign the return value (undefined) to the object as done in the example.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
Example:
clippingPolygons = clippingPolygons && clippingPolygons.destroy();
See:

get(index) → ClippingPolygon

Returns the clipping polygon in the collection at the specified index. Indices are zero-based and increase as polygons are added. Removing a polygon polygon all polygons after it to the left, changing their indices. This function is commonly used with ClippingPolygonCollection#length to iterate over all the polygons in the collection.
Name Type Description
index number The zero-based index of the polygon.
Returns:
The ClippingPolygon at the specified index.
See:

isDestroyed() → boolean

Returns true if this object was destroyed; otherwise, false.

If this object was destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception.
Returns:
true if this object was destroyed; otherwise, false.
See:

remove(polygon) → boolean

Removes the first occurrence of the given ClippingPolygon from the collection.
Name Type Description
polygon ClippingPolygon
Returns:
true if the polygon was removed; false if the polygon was not found in the collection.
See:

removeAll()

Removes all polygons from the collection.
See:
packages/engine
packages/widgets