Viewport

Description

sealed class Tinman.Terrain.Visibility.Viewport

Derived from

Versioned abstract

The Viewport class represents the viewport of a 3D application.

Instances of this class are used to project terrain-space error values and bounding spheres to screen-space. This is done using an isotropic metric, which is derived from the following values:

error' = error * scale / distance
scale  = size / fov

where error is the terrain-space error value, distance is the distance from the terrain vertex to the camera position, size is the viewport size in screen pixels along the field of view, fov is the field of view angle in radians and error' is the resulting screen-space error value.

This class interprets the projection plane as a subsection of a sphere. Then, the field of view angles can then be seen as arc-lengths, which allows them to be greater than 180° (see AdjustFieldOfView).

Public / Constructors

Viewport

public constructor Viewport → (4)

width opt : int32 = 1024

[>0]
The viewport width, in screen pixels.

height opt : int32 = 768

[>0]
The viewport height, in screen pixels.

fieldOfView opt : float64 = 70

[0..360]
The field of view angle, in degrees.

mode opt : FovMode = FovMode.Vertical

The field of view angle mode.

Creates a new instance of Viewport.

Public / Methods

Adjust​Field​Of​View

[Pure]
public static method AdjustFieldOfView → (3)

fov in : float64

The field of view angle, in degrees.

factor in : float64

The scale factor to apply.

spherical in : bool

true to interpret fov in as an arc-length on the unit sphere,
false to assume that a perspective projection is in place and treat fov in as the opening angle along the viewport axis.

returns → float64

The adjusted field-of-view angle, in degrees.

Adjusts the given field of view angle.

Compute​Field​Of​View

[Pure]
public static method ComputeFieldOfView → (5)

width in : int32

[>0]
The viewport width.

height in : int32

[>0]
The viewport height.

fov opt : float64 = 50

[>0]
The desired field-of-view angle (according to mode opt), in degrees.

maximum opt : float64 = 90

[>0]
The maximum field-of-view angle to enforce both horizontally and vertically, in degrees.

mode opt : FovMode = FovMode.Vertical

The field-of-view mode.

returns → float64

The resulting field-of-view angle, in degrees.

Computes a field-of-view angle that avoids fish-eye distortions.

Inside

[Pure]
public method Inside → (4)

eyeX in : float64

X-component of eye vector (point to camera), in camera space (see remarks).

eyeY in : float64

Y-component of eye vector (point to camera), in camera space (see remarks).

eyeZ in : float64

Z-component of eye vector (point to camera), in camera space (see remarks).

radius opt : float64 = 0

Radius of sphere or 0 for a point.

returns → bool

true if the point or sphere is at least partially inside of the viewport frustum,
false if it is outside of it.

Checks if the given point or sphere is at least partially inside of the viewport frustum.

The point position must be specified in camera space: The positive Z-axis is the camera direction, the positive Y-axis is the camera upwards direction and the X-axis is the camera side direction (cartesian handedness is not relevant for this method).

See also

Viewport.FieldOfViewX
Viewport.FieldOfViewY

Project

[Pure]
public method Project → (3)

error in : float64

The terrain-space error value.

distanceToCamera in : float64

Distance to camera, in terrain-space.

useBaseFov opt : bool = false

Use the given base field of view (see BaseFieldOfView) instead of the current field of view?

returns → float64

The screen-space error value.

Projects a given error value from terrain-space to screen-space.

Project​Sqr

[Pure]
public method ProjectSqr → (3)

errorSqr in : float64

The squared terrain-space error value.

distanceToCameraSqr in : float64

Squared distance to camera, in terrain-space.

useBaseFov opt : bool = false

Use the given base field of view (see BaseFieldOfView) instead of the current field of view?

returns → float64

The squared screen-space error value.

Projects a given error value from terrain-space to screen-space.

Set

public method Set → (1)

other in : Viewport

[not-null]
The viewport to copy from.

Copies all properties from the given viewport to this one.

Set​Size

public method SetSize → (2)

width in : int32

[>0]
The viewport width, in pixels.

height in : int32

[>0]
The viewport height, in pixels.

Sets the viewport size.

See also

Viewport.Inside

Unproject

[Pure]
public method Unproject → (3)

error in : float64

The screen-space error value.

distanceToCamera in : float64

Distance to camera, in terrain-space.

useBaseFov opt : bool = false

Use the given base field of view (see BaseFieldOfView) instead of the current field of view?

returns → float64

The terrain-space error value.

Projects a given error value from screen-space to terrain-space.

Unproject​Sqr

[Pure]
public method UnprojectSqr → (3)

errorSqr in : float64

The squared screen-space error value.

distanceToCameraSqr in : float64

Squared distance to camera, in terrain-space.

useBaseFov opt : bool = false

Use the given base field of view (see BaseFieldOfView) instead of the current field of view?

returns → float64

The squared terrain-space error value.

Projects a given error value from screen-space to terrain-space.

Public / Attributes

Aspect​Ratio

public attribute AspectRatio → (get)

value : float64

[>0]
The new aspect ratio (i.e. width divided by height).

The aspect ratio of the viewport.

Base​Field​Of​View

public attribute BaseFieldOfView → (get,set)

value : float64

[0..360]
The base field of view angle, in degrees. Set to 0 to disable the base field of view handling.

The base field of view angle.

Depending on Mode, the angle is either measured along the viewports X-axis (FovMode.Horizontal) or Y-axis (FovMode.Vertical).

When the current field of view of the viewport is smaller than the base field of view angle given by this method, the viewport is considered to be zoomed in. In this case, terrain-space error values of vertices that lie inside the viewport (see Inside) are projected using the actual viewport field of view (i.e. the zoomed in one), whereas error values of the other vertices are projected using the base field of view:

+-----------------------------+
|                             |
|           +-----+           |
|           |ooooo|           |
|           |ooooo|           |
|           |ooooo|           |
|           +-----+           |
|                             |
+-----------------------------+

This way, additional detail due to zooming is only generated in the visible area (the 'o’s in the above figure, which are inside the viewport quadrilateral). Otherwise, additional detail would be introduced into the whole mesh, which would quickly exhaust the vertex capacity.

Defaults to 0.

See also

Viewport.IsZoomed
Viewport.Inside

Field​Of​View

public attribute FieldOfView → (get,set)

value : float64

[0..360]
The current field of view angle, in degrees.

The current field of view angle, in degrees.

Depending on Mode, the angle is either measured along the viewports X-axis ( FovMode.Horizontal) or Y-axis (FovMode.Vertical).

See also

Viewport.Inside

Field​Of​View​X

public attribute FieldOfViewX → (get)

value : float64

[0..360]
The horizontal field-of-view, in degrees.

Returns the field-of-view along the viewport X-axis.

Field​Of​View​Y

public attribute FieldOfViewY → (get)

value : float64

[0..360]
The vertical field-of-view, in degrees.

Returns the field-of-view along the viewport Y-axis.

Height

public attribute Height → (get)

value : int32

[>0]
The viewport height, in pixels.

The viewport height.

See also

Viewport.SetSize

Is​Zoomed

public attribute IsZoomed → (get)

value : bool

true if the viewport is zoomed in, false if not.

Is the viewport currently zoomed in?

See also

Viewport.BaseFieldOfView

Mode

public attribute Mode → (get,set)

value : FovMode

The field of view mode.

The current field of view angle mode.

Defaults to FovMode.Vertical.

Width

public attribute Width → (get)

value : int32

[>0]
The viewport width, in pixels.

The viewport width.

See also

Viewport.SetSize