PerspectiveFrustum - CesiumJS API 文档

new Cesium.PerspectiveFrustum(options)

观景浮雕由6架飞机定义. Each plane is represented by a Cartesian4 object, where the x, y, and z components 定义平面正常的单位矢量, w 组件是飞机从原产地/相机位置起飞.

Name Type Description

options

object

optional 具有下列属性的天体:

Name	Type	Default	Description
`fov`	number		optional 视野的角度( FOV ),用弧度表示.
`aspectRatio`	number		optional Frustum的宽度与其高度的宽度之比.
`near`	number	`1.0`	optional 近平面的距离.
`far`	number	`500000000.0`	optional The distance of the far plane.
`xOffset`	number	`0.0`	optional x 方向的乘数.
`yOffset`	number	`0.0`	optional 向Y方向冲抵.

Example:

const frustum = new Cesium.PerspectiveFrustum({
    fov : Cesium.Math.PI_OVER_THREE,
    aspectRatio : canvas.clientWidth / canvas.clientHeight
    near : 1.0,
    far : 1000.0
});

See:

PerspectiveOffCenterFrustum

Members

static Cesium.PerspectiveFrustum.packedLength : number

用于将对象组合成数组的元素数量.

aspectRatio : number|undefined

Frustum的宽度与其高度的宽度之比.

Default Value: undefined

far : number

远方飞机的距离.

Default Value: 500000000.0

fov : number|undefined

视野的角度( FOV ),用弧度表示. 此角度将被使用如果宽度大于高度, 则作为水平 NT+ 0 , 否则这将是垂直的 NT 0 .

Default Value: undefined

readonly fovy : number|undefined

获得垂直视野的角度,以弧度表示.

Default Value: undefined

readonly infiniteProjectionMatrix : Matrix4

透视投影矩阵以无限远的平面计算.

See:

PerspectiveFrustum#projectionMatrix

near : number

近机之远.

Default Value: 1.0

readonly projectionMatrix : Matrix4

从视图中计算出视角预测矩阵. 如有必要,将重新计算预测矩阵.

See:

PerspectiveOffCenterFrustum#projectionMatrix.
PerspectiveFrustum#infiniteProjectionMatrix

xOffset : number

将frustum向x方向偏移.

Default Value: 0.0

yOffset : number

将阴茎向y方向抵消.

Default Value: 0.0

Methods

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

将所提供的实例存储到所提供的数组中.

Name	Type	Default	Description
`value`	PerspectiveFrustum		包装的价值.
`array`	Array.<number>		装入的阵列.
`startingIndex`	number	`0`	optional The index into the array at which to start packing the elements.

Returns:

装入的阵列

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

从组合的数组中获取实例 .

Name	Type	Default	Description
`array`	Array.<number>		装填的阵列.
`startingIndex`	number	`0`	optional The starting index of the element to be unpacked.
`result`	PerspectiveFrustum		optional 存储结果的对象.

Returns:

未提供修改的结果参数或新的 PerspectFrustum 实例 .

clone(result) → PerspectiveFrustum

返回 PerspectFrustum 实例的复制件.

Name	Type	Description
`result`	PerspectiveFrustum	optional 存储结果的对象 .

Returns:

未提供修改的结果参数或新的 PerspectFrustum 实例 .

computeCullingVolume(position, direction, up) → CullingVolume

为这个 flustum 创建调制音量 .

Name	Type	Description
`position`	Cartesian3	眼处.
`direction`	Cartesian3	风景方向.
`up`	Cartesian3	上升方向.

Returns:

在给定的位置和方向上,有一个凸起的卷.

Example:

// Check if a bounding volume intersects the frustum.
const cullingVolume = frustum.computeCullingVolume(cameraPosition, cameraDirection, cameraUp);
const intersect = cullingVolume.computeVisibility(boundingVolume);

equals(other) → boolean

比较所提供的 PerspectFrustum 组件并返回 -NT+0+Treal NT+1+,如果两者是相等的, NT+2+false NT+3+否则.

Name	Type	Description
`other`	PerspectiveFrustum	optional 右手侧透视Frustum.

Returns:

-NT+0+Treal NT+1+,如果两者是相等的, NT+2+false NT+3+否则.

equalsEpsilon(other, relativeEpsilon, absoluteEpsilon) → boolean

比较所提供的 PerspectFrustum 组件并返回如果通过绝对或相对耐性测试, -NT+0+false NT+1+否则.

Name	Type	Default	Description
`other`	PerspectiveFrustum		右手侧透视Frustum.
`relativeEpsilon`	number		相对epsilon的耐受性用于平等测试.
`absoluteEpsilon`	number	`相对Epsilon`	optional 绝对的埃皮西隆耐受性用于平等测试.

Returns:

NT########################################################### ##################################################################################################################################################################################################.

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

返回像素的宽度和高度,以米计.

Name	Type	Description
`drawingBufferWidth`	number	绘图缓冲器的宽度 .
`drawingBufferHeight`	number	绘画缓冲器的高度.
`distance`	number	距离近机以米计.
`pixelRatio`	number	从像素空间到协调空间的缩放因子.
`result`	Cartesian2	存储结果的对象 .

Returns:

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:

DeveloperError : drawingBufferWidth must be greater than zero.
DeveloperError : drawingBufferHeight must be greater than zero.
DeveloperError : pixelRatio must be greater than zero.

Examples:

// 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());