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:
|
使用示例:
const maxRadii = ellipsoid.maximumRadius;
const frustum = new Cesium.OrthographicOffCenterFrustum();
frustum.right = maxRadii * Cesium.Math.PI;
frustum.left = -c.frustum.right;
frustum.top = c.frustum.right * (canvas.clientHeight / canvas.clientWidth);
frustum.bottom = -c.frustum.top;
frustum.near = 0.01 * maxRadii;
frustum.far = 50.0 * maxRadii;成员(属性)
The bottom clipping plane.
-
默认值:
undefined
The distance of the far plane.
-
默认值:
500000000.0;
The left clipping plane.
-
默认值:
undefined
The distance of the near plane.
-
默认值:
1.0
readonly projectionMatrix : Matrix4
Gets the orthographic projection matrix computed from the view frustum.
The right clipping plane.
-
默认值:
undefined
The top clipping plane.
-
默认值:
undefined
方法
Returns a duplicate of a OrthographicOffCenterFrustum instance.
| 参数名称 | 类型 | 描述信息 |
|---|---|---|
result |
OrthographicOffCenterFrustum | 可选 The object onto which to store the result. |
返回值:
The modified result parameter or a new OrthographicOffCenterFrustum 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 OrthographicOffCenterFrustum componentwise and returns
true if they are equal, false otherwise.
| 参数名称 | 类型 | 描述信息 |
|---|---|---|
other |
OrthographicOffCenterFrustum | 可选 The right hand side OrthographicOffCenterFrustum. |
返回值:
true if they are equal, false otherwise.
Compares the provided OrthographicOffCenterFrustum 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 |
OrthographicOffCenterFrustum | The right hand side OrthographicOffCenterFrustum. | |
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:
-
DeveloperError : drawingBufferWidth must be greater than zero.
-
DeveloperError : drawingBufferHeight must be greater than zero.
-
DeveloperError : pixelRatio must be greater than zero.
使用示例:
// Example 1
// Get the width and height of a pixel.
const pixelSize = camera.frustum.getPixelDimensions(scene.drawingBufferWidth, scene.drawingBufferHeight, 0.0, scene.pixelRatio, new Cesium.Cartesian2());