ASGE::Camera Class Reference

#include <Camera.hpp>

Classes
struct	CameraView

Public Types
using	Translation = std::array< float, 3 >

Public Member Functions
	Camera ()=default
	Camera (float width, float height)
	Camera (Point2D focal_point, float width, float height)
virtual	~Camera ()=default
void	lookAt (Point2D focal_point)
virtual void	update (const ASGE::GameTime &game_time)
virtual void	translate (float x, float y, float z)
virtual void	translateX (float x)
virtual void	translateY (float y)
virtual void	translateZ (float zoom)
void	setZoom (float zoom)
void	resize (float width, float height)
CameraView	getView () const
float	getZoom () const
const ASGE::Point2D &	position () const
void	clamp (const CameraView &)

Detailed Description

A 2D orthogonal camera class.

The Camera class is designed as a simple way to alter the view being drawn to the screen. The view described by the camera will be scaled to the viewport, so it is recommend to size it identically to the viewport or to at least use the same aspect ratio to prevent scaling artifacts. This basic implementation provides translation in the X and Y axis and use of Z to control the zoom level of the camera. In order to apply a translation to the camera, the translate function must be called. The default implementation is to move the camera by the requested translation amount.There is no damping or smoothing applied. If this is required, the class should be inherited from and the update function overridden.

Physically Based Rendering: From Theory To Implementation, © 2004-2019 Matt Pharr, Wenzel Jakob, and Greg Humphreys

Usage:

ASGE::Camera camera {1024, 768};
camera.translateY(-2048 * gt.deltaInSecs());
camera.update(gt);
renderer->setProjectionMatrix(camera.getView());

Definition at line 54 of file Camera.hpp.

Constructor & Destructor Documentation

Camera() [1/3]

ASGE::Camera::Camera ( )

default

Default constructor with no predefined view.

Note

Not providing a view will result in nothing being rendered.

Camera() [2/3]

ASGE::Camera::Camera	(	float	width,
		float	height
	)

Constructs the camera and sets the view width and height.

Whilst the camera view's width and height will be set, it assumed that the camera will be looking at {0,0}. This is considered the center of the camera's view and is analogous to its focal point. The final view will be sized accordingly i.e. {-width, width} and {-height, height}.

Parameters

[in]	width	The width of the camera's view.
[in]	height	The height of the camera's view.

Camera() [3/3]

ASGE::Camera::Camera	(	Point2D	focal_point,
		float	width,
		float	height
	)

Constructs a camera, with a focal point and a view size.

These parameters will dictate where the camera is looking and how much of the scene it will show. It's important to note that the focal point of a camera is the middle of it's view, not the top left (0,0) i.e. {-width, width} and {-height, height}.

Parameters

[in]	focal_point	The camera's focal point.
[in]	width	The width of the camera's view.
[in]	height	The height of the camera's view.

~Camera()

virtual ASGE::Camera::~Camera ( )

virtualdefault

Default destructor.

Member Function Documentation

clamp()

void ASGE::Camera::clamp

(

const CameraView &

)

Clamps the camera view.

It is often desirable to clamp the field of vision for the camera to ensure only specific regions of the game screen are shown. Consider a tile map where the camera should not exceed the width or height of the map. This function can be used to clamp the view to a set of predefined values, representing min_x, max_x, min_y and max_y. These would then be used to simply clamp the view's x and y positions.

Parameters

[in]

view_bounds

The four bounds to use in xy space.

getView()

CameraView ASGE::Camera::getView

(

)

const

A view that describes the camera's framing.

Use this to frame the action, which in turn is rendered to the window. This view can be used directly to control the projection matrix used for mapping to the game window. Everything inside the view will be mapped directly to the screens viewport. The bounding volume controls the depth of items rendered.

Returns

ASGE::Camera::CameraView

Physically Based Rendering: From Theory To Implementation, © 2004-2019 Matt Pharr, Wenzel Jakob, and Greg Humphreys

getZoom()

float ASGE::Camera::getZoom

(

)

const

Retrieves the current zoom level for the camera.

Returns

The camera's zoom.

lookAt()

void ASGE::Camera::lookAt

(

Point2D

focal_point

)

Set's the camera's focal point.

Parameters

focal_point

The new center point of the camera's view.

See also

ASGE::Point2D

position()

const ASGE::Point2D& ASGE::Camera::position

(

)

const

Retrieves the camera's current position on the XY axis.

Returns

The camera's position.

resize()

void ASGE::Camera::resize	(	float	width,
		float	height
	)

Resizes the camera's view.

Note

This does not maintain the aspect ratio of the camera.

Parameters

[in]	width	The new width of the camera's view.
[in]	height	The new height of the camera's view.

setZoom()

void ASGE::Camera::setZoom

(

float

zoom

)

Adjust the camera's zoom.

Parameters

[in]

zoom

The amount to adjust the zoom by.

translate()

virtual void ASGE::Camera::translate ( float  x, float  y, float  z  )

virtual

Adds a translation amount in all three axis.

The translation is not applied until the update function is called. You can think of the translation vector applied to the camera's movement.

Parameters

[in]	x	The amount to move in the x axis.
[in]	y	The amount to move in the y axis.
[in]	z	The amount of zoom to apply.

translateX()

virtual void ASGE::Camera::translateX ( float  x )

virtual

Moves the camera's view in the x axis.

Parameters

[in]

x

The amount to translate the view by.

translateY()

virtual void ASGE::Camera::translateY ( float  y )

virtual

Moves the camera's view in the y axis.

Parameters

[in]

y

The amount to translate the view by.

translateZ()

virtual void ASGE::Camera::translateZ ( float  zoom )

virtual

Adjust the camera's zoom.

Parameters

[in]

zoom

The amount to adjust the zoom by.

update()

virtual void ASGE::Camera::update ( const ASGE::GameTime &  game_time )

virtual

Does nothing.

Override this function if you wish to add more complex behaviours such as smoothing and delta-time related animations to the camera's movement.

Parameters

[in]

game_time

The game's duration and the frame time delta.

---

The documentation for this class was generated from the following file:

• Camera.hpp