PerspectiveFrustum

new Cesium.PerspectiveFrustum(options)

The viewing frustum is defined by 6 planes. Each plane is represented by a Cartesian4 object, where the x, y, and z components define the unit vector normal to the plane, and the w component is the distance of the plane from the origin/camera position.
参数名称 类型 描述信息
options object 可选 An object with the following properties:
参数名称 类型 默认值 描述信息
fov number 可选 The angle of the field of view (FOV), in radians.
aspectRatio number 可选 The aspect ratio of the frustum's width to it's height.
near number 1.0 可选 The distance of the near plane.
far number 500000000.0 可选 The distance of the far plane.
xOffset number 0.0 可选 The offset in the x direction.
yOffset number 0.0 可选 The offset in the y direction.
使用示例:
const frustum = new Cesium.PerspectiveFrustum({
    fov : Cesium.Math.PI_OVER_THREE,
    aspectRatio : canvas.clientWidth / canvas.clientHeight
    near : 1.0,
    far : 1000.0
});
参考:

成员(属性)

static Cesium.PerspectiveFrustum.packedLength : number

The number of elements used to pack the object into an array.

aspectRatio : number|undefined

The aspect ratio of the frustum's width to it's height.
默认值: undefined
The distance of the far plane.
默认值: 500000000.0
The angle of the field of view (FOV), in radians. This angle will be used as the horizontal FOV if the width is greater than the height, otherwise it will be the vertical FOV.
默认值: undefined

readonly fovy : number|undefined

Gets the angle of the vertical field of view, in radians.
默认值: undefined

readonly infiniteProjectionMatrix : Matrix4

The perspective projection matrix computed from the view frustum with an infinite far plane.
参考:
The distance of the near plane.
默认值: 1.0
Gets the perspective projection matrix computed from the view frustum. If necessary, the projection matrix will be recomputed.
参考:
Offsets the frustum in the x direction.
默认值: 0.0
Offsets the frustum in the y direction.
默认值: 0.0

方法

static Cesium.PerspectiveFrustum.pack(value, array, startingIndex)Array.<number>

Stores the provided instance into the provided array.
参数名称 类型 默认值 描述信息
value PerspectiveFrustum The value to pack.
array Array.<number> The array to pack into.
startingIndex number 0 可选 The index into the array at which to start packing the elements.
返回值:
The array that was packed into

static Cesium.PerspectiveFrustum.unpack(array, startingIndex, result)PerspectiveFrustum

Retrieves an instance from a packed array.
参数名称 类型 默认值 描述信息
array Array.<number> The packed array.
startingIndex number 0 可选 The starting index of the element to be unpacked.
result PerspectiveFrustum 可选 The object into which to store the result.
返回值:
The modified result parameter or a new PerspectiveFrustum instance if one was not provided.
Returns a duplicate of a PerspectiveFrustum instance.
参数名称 类型 描述信息
result PerspectiveFrustum 可选 The object onto which to store the result.
返回值:
The modified result parameter or a new PerspectiveFrustum instance if one was not provided.

computeCullingVolume(position, direction, up)CullingVolume

Creates a culling volume for this frustum.
参数名称 类型 描述信息
position Cartesian3 The eye position.
direction Cartesian3 The view direction.
up Cartesian3 The up direction.
返回值:
A culling volume at the given position and orientation.
使用示例:
// Check if a bounding volume intersects the frustum.
const cullingVolume = frustum.computeCullingVolume(cameraPosition, cameraDirection, cameraUp);
const intersect = cullingVolume.computeVisibility(boundingVolume);
Compares the provided PerspectiveFrustum componentwise and returns true if they are equal, false otherwise.
参数名称 类型 描述信息
other PerspectiveFrustum 可选 The right hand side PerspectiveFrustum.
返回值:
true if they are equal, false otherwise.

equalsEpsilon(other, relativeEpsilon, absoluteEpsilon)boolean

Compares the provided PerspectiveFrustum componentwise and returns true if they pass an absolute or relative tolerance test, false otherwise.
参数名称 类型 默认值 描述信息
other PerspectiveFrustum The right hand side PerspectiveFrustum.
relativeEpsilon number The relative epsilon tolerance to use for equality testing.
absoluteEpsilon number relativeEpsilon 可选 The absolute epsilon tolerance to use for equality testing.
返回值:
true if this and other are within the provided epsilon, false otherwise.

getPixelDimensions(drawingBufferWidth, drawingBufferHeight, distance, pixelRatio, result)Cartesian2

Returns the pixel's width and height in meters.
参数名称 类型 描述信息
drawingBufferWidth number The width of the drawing buffer.
drawingBufferHeight number The height of the drawing buffer.
distance number The distance to the near plane in meters.
pixelRatio number The scaling factor from pixel space to coordinate space.
result Cartesian2 The object onto which to store the result.
返回值:
The modified result parameter or a new instance of Cartesian2 with the pixel's width and height in the x and y properties, respectively.
Throws:
使用示例s:
// Example 1
// Get the width and height of a pixel.
const pixelSize = camera.frustum.getPixelDimensions(scene.drawingBufferWidth, scene.drawingBufferHeight, 1.0, scene.pixelRatio, new Cesium.Cartesian2());
// Example 2
// Get the width and height of a pixel if the near plane was set to 'distance'.
// For example, get the size of a pixel of an image on a billboard.
const position = camera.position;
const direction = camera.direction;
const toCenter = Cesium.Cartesian3.subtract(primitive.boundingVolume.center, position, new Cesium.Cartesian3());      // vector from camera to a primitive
const toCenterProj = Cesium.Cartesian3.multiplyByScalar(direction, Cesium.Cartesian3.dot(direction, toCenter), new Cesium.Cartesian3()); // project vector onto camera direction vector
const distance = Cesium.Cartesian3.magnitude(toCenterProj);
const pixelSize = camera.frustum.getPixelDimensions(scene.drawingBufferWidth, scene.drawingBufferHeight, distance, scene.pixelRatio, new Cesium.Cartesian2());