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 maxRadii = ellipsoid.maximumRadius;
var frustum = new Cesium.OrthographicFrustum();
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;
Members
-
The bottom clipping plane.
-
Default Value:
undefined
-
The distance of the far plane.
-
Default Value:
500000000.0;
-
The left clipping plane.
-
Default Value:
undefined
-
The distance of the near plane.
-
Default Value:
1.0
-
readonlyprojectionMatrix : Matrix4
-
Gets the orthographic projection matrix computed from the view frustum.
-
The right clipping plane.
-
Default Value:
undefined
-
The top clipping plane.
-
Default Value:
undefined
Methods
-
clone(result) → OrthographicFrustum
-
Returns a duplicate of a OrthographicFrustum instance.
Name Type Description result
OrthographicFrustum 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
-
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);
-
Compares the provided OrthographicFrustum componentwise and returns
true
if they are equal,false
otherwise.Name Type Description other
OrthographicFrustum optional The right hand side OrthographicFrustum. Returns:
true
if they are equal,false
otherwise. -
getPixelDimensions(drawingBufferWidth, drawingBufferHeight, distance, result) → Cartesian2
-
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 ofCartesian2
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.
Example:
// Example 1 // Get the width and height of a pixel. var pixelSize = camera.frustum.getPixelDimensions(scene.drawingBufferWidth, scene.drawingBufferHeight, 0.0, new Cesium.Cartesian2());
-