PerspectiveFrustum

PerspectiveFrustum

new

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 PerspectiveFrustum();
frustum.fovy = CesiumMath.PI_OVER_THREE;
frustum.aspectRatio = canvas.clientWidth / canvas.clientHeight;
frustum.near = 1.0;
frustum.far = 2.0;
See:
Source:

Members

:Number

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

:Number

The distance of the far plane.
Default Value:
  • 500000000.0

:Number

The angle of the field of view, in radians.
Default Value:
  • undefined

:Number

The distance of the near plane.
Default Value:
  • 1.0

Methods

Returns a duplicate of a PerspectiveFrustum instance.

Returns:
PerspectiveFrustum A new copy of the PerspectiveFrustum instance.

Creates a culling volume for this frustum.

Parameters:
Name Type Description
position Cartesian3 The eye position.
direction Cartesian3 The view direction.
up Cartesian3 The up direction.
Throws:
Returns:
CullingVolume 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.getVisibility(boundingVolume);

Compares the provided PerspectiveFrustum componentwise and returns true if they are equal, false otherwise.

Parameters:
Name Type Argument Description
other PerspectiveFrustum <optional>
The right hand side PerspectiveFrustum.
Returns:
Boolean true if they are equal, false otherwise.

Returns the perspective projection matrix computed from the view frustum with an infinite far plane.

Returns:
Matrix4 The infinite perspective projection matrix.
See:

Returns the pixel's width and height in meters.

Parameters:
Name Type Argument Default Description
canvasDimensions Cartesian2 A Cartesian2 with width and height in the x and y properties, respectively.
distance Number <optional>
near plane distance The distance to the near plane in meters.
Throws:
Returns:
Cartesian2 A Cartesian2 with the pixel's width and height in the x and y properties, respectively.
Example
// Example 1
// Get the width and height of a pixel.
var pixelSize = camera.frustum.getPixelSize({
    width : canvas.clientWidth,
    height : canvas.clientHeight
});

// 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 = primitive.boundingVolume.center.subtract(position);      // vector from camera to a primitive
var toCenterProj = direction.multiplyByScalar(direction.dot(toCenter)); // project vector onto camera direction vector
var distance = toCenterProj.magnitude();
var pixelSize = camera.frustum.getPixelSize({
    width : canvas.clientWidth,
    height : canvas.clientHeight
}, distance);

Returns the perspective projection matrix computed from the view frustum.

Returns:
Matrix4 The perspective projection matrix.
See: