public static float GetViewNormalizedDistance(
	float distance,
	Matrix44F projection
)

Public Shared Function GetViewNormalizedDistance ( 
	distance As Single,
	projection As Matrix44F
) As Single

public:
static float GetViewNormalizedDistance(
	float distance, 
	Matrix44F projection
)

static member GetViewNormalizedDistance : 
        distance : float32 * 
        projection : Matrix44F -> float32 

Parameters

distance

Type: SystemSingle
The 3D Euclidean distance between the object and the camera.

projection

Type: DigitalRune.Mathematics.AlgebraMatrix44F
The projection transformation.

Return Value

The view-normalized distance is defined as:

distance_normalized = distance / yScale

where distance is the 3D Euclidean distance between the camera and the object. yScale is the second diagonal entry of the projection matrix.

For symmetric perspective projections the above equation is the same as

distance_normalized = distance * tan(fov_Y / 2)

where fov_Y is the camera's vertical field-of-view.

In other words, the view-normalized distance is the camera distance times a camera correction factor. The correction factor accounts for the camera field-of-view. The resulting value is inversely proportional to the screen size of the object and independent of the current field-of-view. It can be used to specify LOD distances or similar metrics.

Note that tan(fov_Y/2) is 1 if the fov_Y = 90°. This means that distance and view-normalized distance are identical for a camera with a vertical field-of-view of 90°. (This 90° FOV camera is the "reference camera".)

The view-normalized distance is only defined for cameras with perspective projections. The result is undefined for orthographic projections!

Reference