I represent a viewing frustum, defined by the following values:

typedef struct B3DViewingFrustum {
float left;
float right;
float top;
float bottom;
float near;
float far;
} B3DViewingFrustum;

The frustum can be converted into either a ortho matrix (having no perspective distortion) or a perspective matrix for use in the Balloon 3D render engine.

	converting
	asFrustum asOrthoMatrix asPerspectiveMatrix

	private
	asOrthoMatrixInto: asPerspectiveMatrixInto: computeFromNear:far:fov:aspect:

	accessing	top
	bottom
	bottom:
	far
	far:
	left
	left:
	near
	near:
	right
	right:
	top
	top:

	converting	top
	asFrustum
	asOrthoMatrix
	asPerspectiveMatrix

	private	top
	asOrthoMatrixInto:
	asPerspectiveMatrixInto:
	computeFromNear:far:fov:aspect: Compute the viewing frustum from the given values

	instance creation	top
	near:far:fov:aspect:
	numElements