Struct draw2d::camera::OrthoCamera

pub struct OrthoCamera { /* fields omitted */ }

Implementations

impl OrthoCamera

pub fn with_viewport(viewport_height: f32, aspect_ratio: f32) -> Self

Build a new camera with a given viewport height and aspect ratio.

Params

• viewport_height defines the height of the view rectangle in world space.
• aspect_ratio is the ratio of the desired viewport’s width/height.

pub fn as_matrix(&self) -> Matrix4<f32>

Get the camera’s full transformation matrix. This can be passed to a shader for transformations.

pub fn bounds(&self) -> Rect<f32>

The camera’s bounds in world-space.

Example

let ortho = OrthoCamera::with_viewport(1.0, 2.0);
let bounds = ortho.bounds();

assert_relative_eq!(bounds.left, -1.0);
assert_relative_eq!(bounds.right, 1.0);
assert_relative_eq!(bounds.top, 0.5);
assert_relative_eq!(bounds.bottom, -0.5);

pub fn set_world_position(&mut self, world_pos: &Point2<f32>)

Set the camera’s position in world-space.

Example

let mut ortho = OrthoCamera::with_viewport(2.0, 1.0);
ortho.set_world_position(&na::Point2::new(30.0, -0.5));

assert_relative_eq!(
  ortho.world_position(),
  na::Point2::new(30.0, -0.5)
);

let bounds = ortho.bounds();
assert_relative_eq!(bounds.left, -1.0 + 30.0);
assert_relative_eq!(bounds.right, 1.0 + 30.0);
assert_relative_eq!(bounds.top, 1.0 - 0.5);
assert_relative_eq!(bounds.bottom, -1.0 - 0.5);

pub fn world_position(&self) -> Point2<f32>

Get the camera’s position in world space.

Example

let pos = OrthoCamera::with_viewport(1.0, 1.0).world_position();

assert_relative_eq!(pos, na::Point2::new(0.0, 0.0));

pub fn set_aspect_ratio(&mut self, desired_aspect_ratio: f32)

Resize the viewport’s width such that the viewing rectangle has the desired aspect ratio.

Example

let mut ortho = OrthoCamera::with_viewport(1.0, 1.0);
ortho.set_aspect_ratio(2.0);

let bounds = ortho.bounds();
assert_relative_eq!(bounds.left, -1.0);
assert_relative_eq!(bounds.right, 1.0);
assert_relative_eq!(bounds.top, 0.5);
assert_relative_eq!(bounds.bottom, -0.5);

pub fn aspect_ratio(&self) -> f32

The camera viewport’s aspect ratio.

pub fn viewport_height(&self) -> f32

Get the height of the viewport.

pub fn viewport_width(&self) -> f32

Get the width of the viewport.

pub fn set_viewport_height(&mut self, desired_height: f32)

Set the viewport’s height to a new value.

Automatically resizes the viewport’s width to maintain the current aspect ratio.

Example

// a camera which is 3x as wide as it is tall
let mut ortho = OrthoCamera::with_viewport(2.0, 3.0);

assert_relative_eq!(ortho.aspect_ratio(), 3.0);
assert_relative_eq!(ortho.viewport_height(), 2.0);
assert_relative_eq!(ortho.viewport_width(), 6.0);

ortho.set_viewport_height(3.3);

assert_relative_eq!(ortho.aspect_ratio(), 3.0);
assert_relative_eq!(ortho.viewport_height(), 3.3);
assert_relative_eq!(ortho.viewport_width(), 9.9);

pub fn unproject_vec(&self, ndc: &Vector2<f32>) -> Vector2<f32>

Unproject a vector from normalized device coordinates (NDC) to view space.

Vectors are just a direction and a magnitude, so this transformation does not apply the camera’s translation in world space.

Example

// a camera which is 3x as wide as it is tall
let mut ortho = OrthoCamera::with_viewport(2.0, 3.0);

// the camera's world position is ignored when unprojecting a vector
ortho.set_world_position(&na::Point2::new(100.0, -34523.0));

// Vulkan ndc coords have Y ranging from -1 at the top of the screen,
// to 1 at the bottom of the screen.
let top_right_ndc = na::Vector2::new(1.0, -1.0);

// The unprojected vector should point to the top right of the viewport
// rectangle, but is not influenced by the camera's world position.
let unprojected = ortho.unproject_vec(&top_right_ndc);
assert_relative_eq!(unprojected, na::Vector2::new(3.0, 1.0));

pub fn unproject_point(&self, ndc: &Point2<f32>) -> Point2<f32>

Unproject a point from normalized device coordinates (NDC) to world space.

Points are logically a specific location in space. As such, the point’s coordinates will be transformed b ythe camera’s location in world space.

e.g. this method returns where the ndc point would actually be located in world coordinates.

Example

// a camera which is 3x as wide as it is tall
let mut ortho = OrthoCamera::with_viewport(2.0, 3.0);

// the camera's world position is ignored when unprojecting a vector
ortho.set_world_position(&na::Point2::new(100.0, -34523.0));

// Vulkan ndc coords have Y ranging from -1 at the top of the screen,
// to 1 at the bottom of the screen.
let bottom_left_ndc = na::Point2::new(-1.0, 1.0);

// The unprojected point should account for both the camera's viewing
// rectangle, and the camera's world position.
let unprojected = ortho.unproject_point(&bottom_left_ndc);
assert_relative_eq!(
    unprojected,
    na::Point2::new(-3.0, -1.0) + ortho.world_position().coords
);

Trait Implementations

impl Clone for OrthoCamera

fn clone(&self) -> OrthoCamera

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for OrthoCamera

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq<OrthoCamera> for OrthoCamera

fn eq(&self, other: &OrthoCamera) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &OrthoCamera) -> bool

This method tests for !=.

impl Copy for OrthoCamera

impl StructuralPartialEq for OrthoCamera