PerspectiveFrustum

new Cesium.PerspectiveFrustum()
Scene/PerspectiveFrustum.js 33

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.
Example:
var frustum = new Cesium.PerspectiveFrustum();
frustum.aspectRatio = canvas.clientWidth / canvas.clientHeight;
frustum.fov = Cesium.Math.PI_OVER_THREE;
frustum.near = 1.0;
frustum.far = 2.0;
See:

Members

aspectRatio : Number
Scene/PerspectiveFrustum.js 54

The aspect ratio of the frustum's width to it's height.
Default Value: undefined

far : Number
Scene/PerspectiveFrustum.js 70

The distance of the far plane.
Default Value: 500000000.0

fov : Number
Scene/PerspectiveFrustum.js 43

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.
Default Value: undefined

readonlyfovy : Number
Scene/PerspectiveFrustum.js 177

Gets the angle of the vertical field of view, in radians.
Default Value: undefined

readonlyinfiniteProjectionMatrix : Matrix4
Scene/PerspectiveFrustum.js 163

The perspective projection matrix computed from the view frustum with an infinite far plane.
See:

near : Number
Scene/PerspectiveFrustum.js 62

The distance of the near plane.
Default Value: 1.0

readonlyprojectionMatrix : Matrix4
Scene/PerspectiveFrustum.js 148

Gets the perspective projection matrix computed from the view frustum.
See:

xOffset : Number
Scene/PerspectiveFrustum.js 78

Offsets the frustum in the x direction.
Default Value: 0.0

yOffset : Number
Scene/PerspectiveFrustum.js 86

Offsets the frustum in the y direction.
Default Value: 0.0

Methods

clone(result) → PerspectiveFrustum
Scene/PerspectiveFrustum.js 253

Returns a duplicate of a PerspectiveFrustum instance.
Name Type Description
result PerspectiveFrustum optional The object onto which to store the result.
Returns:
The modified result parameter or a new PerspectiveFrustum instance if one was not provided.

computeCullingVolume(position, direction, up) → CullingVolume
Scene/PerspectiveFrustum.js 209

Creates a culling volume for this frustum.
Name Type Description
position Cartesian3 The eye position.
direction Cartesian3 The view direction.
up Cartesian3 The up direction.
Returns:
A culling volume at the given position and orientation.
Example:
// Check if a bounding volume intersects the frustum.
var cullingVolume = frustum.computeCullingVolume(cameraPosition, cameraDirection, cameraUp);
var intersect = cullingVolume.computeVisibility(boundingVolume);

equals(other) → Boolean
Scene/PerspectiveFrustum.js 281

Compares the provided PerspectiveFrustum componentwise and returns true if they are equal, false otherwise.
Name Type Description
other PerspectiveFrustum optional The right hand side PerspectiveFrustum.
Returns:
true if they are equal, false otherwise.

getPixelDimensions(drawingBufferWidth, drawingBufferHeight, distance, result) → Cartesian2
Scene/PerspectiveFrustum.js 242

Returns the pixel's width and height in meters.
Name Type Description
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.
result Cartesian2 The object onto which to store the result.
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:
Examples:
// Example 1
// Get the width and height of a pixel.
var pixelSize = camera.frustum.getPixelDimensions(scene.drawingBufferWidth, scene.drawingBufferHeight, 1.0, new 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.
var position = camera.position;
var direction = camera.direction;
var toCenter = Cesium.Cartesian3.subtract(primitive.boundingVolume.center, position, new Cesium.Cartesian3());      // vector from camera to a primitive
var toCenterProj = Cesium.Cartesian3.multiplyByScalar(direction, Cesium.Cartesian3.dot(direction, toCenter), new Cesium.Cartesian3()); // project vector onto camera direction vector
var distance = Cesium.Cartesian3.magnitude(toCenterProj);
var pixelSize = camera.frustum.getPixelDimensions(scene.drawingBufferWidth, scene.drawingBufferHeight, distance, new Cartesian2());