rendering_engine::Camera2D Class Reference

Represents a 2D camera with position, rotation, and zoom control. More...

#include <camera_2d.hpp>

Public Member Functions
	Camera2D (IApplication &app)
	Constructs a 2D camera at the origin, with no rotation and unit zoom.
virtual	~Camera2D ()=default
	Virtual destructor.
virtual void	Initialize ()
	Initializes the camera (calls Reset()).
virtual void	Update (float deltaTime)
	Updates the camera logic (no-op for now).
void	SetViewportSize (float width, float height)
	Sets the viewport dimensions used to compute the projection matrix.
glm::mat4	GetProjectionMatrix () const
	Returns the current orthographic projection matrix.
void	SetPosition (const glm::vec2 &position)
	Sets the camera position.
void	SetRotation (float angleDegrees)
	Sets the camera rotation angle in degrees (counterclockwise, around Z).
void	SetZoom (float zoom)
	Sets the camera zoom (uniform scale).
void	Reset ()
	Resets the camera to the default view (origin, zero rotation, unit zoom).
glm::vec2	GetPosition () const
	Gets the camera position.
float	GetRotation () const
	Gets the camera rotation angle in degrees.
float	GetZoom () const
	Gets the current zoom factor.
const glm::mat4 &	GetWorldView () const
	Gets the world-view (model) matrix for the camera.

Protected Member Functions
glm::mat4	ComputeOrthographicMatrix (float left, float right, float top, float bottom, float nearPlane, float farPlane) const

Protected Attributes
IApplication &	mApp
std::unique_ptr< SceneComponent2D >	mSceneComponent
glm::vec2	mViewportSize

Detailed Description

Represents a 2D camera with position, rotation, and zoom control.

Camera2D defines the view in a 2D scene, using a SceneComponent2D for transform (position, rotation, zoom). The camera provides basic pan, rotation, and uniform zoom features.

The engine uses a left-handed coordinate system:

• X+ : Right
• Y+ : Up Rotation is counterclockwise, in degrees, around the Z axis (out of the screen).

By default, the camera is at the origin, with zero rotation and unit zoom.

See also

rendering_engine::SceneComponent2D

Definition at line 35 of file camera_2d.hpp.

Constructor & Destructor Documentation

Camera2D()

rendering_engine::Camera2D::Camera2D

(

IApplication &

app

)

Constructs a 2D camera at the origin, with no rotation and unit zoom.

Definition at line 8 of file camera_2d.cpp.

    :
    mApp(app),
    mSceneComponent(std::make_unique<SceneComponent2D>()),
    mViewportSize(glm::vec2(0.0f, 0.0f))
{}

~Camera2D()

virtual rendering_engine::Camera2D::~Camera2D ( )

virtualdefault

Virtual destructor.

Member Function Documentation

ComputeOrthographicMatrix()

glm::mat4 rendering_engine::Camera2D::ComputeOrthographicMatrix ( float left, float right, float top, float bottom, float nearPlane, float farPlane ) const

protected

Definition at line 92 of file camera_2d.cpp.

{
    glm::mat4 result(1.0f);
 
    result[0][0] = 2.0f / (right - left);
    result[1][1] = 2.0f / (bottom - top);
    result[2][2] = 1.0f / (farPlane - nearPlane);
 
    result[3][0] = -(right + left) / (right - left);
    result[3][1] = -(bottom + top) / (bottom - top);
    result[3][2] = -nearPlane / (farPlane - nearPlane);
 
    return result;
}

GetPosition()

glm::vec2 rendering_engine::Camera2D::GetPosition

(

)

const

Gets the camera position.

Returns

2D position (glm::vec2).

Definition at line 72 of file camera_2d.cpp.

{
    return mSceneComponent->GetPosition();
}

GetProjectionMatrix()

glm::mat4 rendering_engine::Camera2D::GetProjectionMatrix

(

)

const

Returns the current orthographic projection matrix.

The matrix is built from the camera�s viewport size, and is typically multiplied with the view (world) matrix to transform coordinates into clip space.

Returns

4�4 orthographic projection matrix.

Definition at line 30 of file camera_2d.cpp.

{
    float halfWidth = mViewportSize.x * 0.5f;
    float halfHeight = mViewportSize.y * 0.5f;
 
    float left = -halfWidth;
    float right = halfWidth;
    float bottom = -halfHeight;
    float top = halfHeight;
    float near = -1.0f;
    float far = 1.0f;
 
    return glm::ortho(left, right, bottom, top, near, far);
}

GetRotation()

float rendering_engine::Camera2D::GetRotation

(

)

const

Gets the camera rotation angle in degrees.

Returns

Rotation angle (degrees).

Definition at line 77 of file camera_2d.cpp.

{
    return mSceneComponent->GetRotation();
}

GetWorldView()

const glm::mat4 & rendering_engine::Camera2D::GetWorldView

(

)

const

Gets the world-view (model) matrix for the camera.

Returns

Model/view matrix (glm::mat3).

Note

Use this to transform between world and screen space for rendering.

Definition at line 87 of file camera_2d.cpp.

{
    return mSceneComponent->GetModelMatrix();
}

GetZoom()

float rendering_engine::Camera2D::GetZoom

(

)

const

Gets the current zoom factor.

Returns

Zoom factor.

Definition at line 82 of file camera_2d.cpp.

{
    return mSceneComponent->GetScale().x;
}

Initialize()

void rendering_engine::Camera2D::Initialize ( )

virtual

Initializes the camera (calls Reset()).

Definition at line 15 of file camera_2d.cpp.

{
    Reset();
 
}

Reset()

void rendering_engine::Camera2D::Reset

(

)

Resets the camera to the default view (origin, zero rotation, unit zoom).

Definition at line 60 of file camera_2d.cpp.

{
    const glm::vec2 startPos = glm::vec2(0.0f, 0.0f);
    const float startRot = 0.0f;
    const float startZoom = 1.0f;
    mSceneComponent->SetPosition(startPos);
    mSceneComponent->SetRotation(startRot);
    mSceneComponent->SetScale(glm::vec2(startZoom, startZoom));
 
    SetViewportSize(mApp.GetScreenSettings().width, mApp.GetScreenSettings().height);
}

SetPosition()

void rendering_engine::Camera2D::SetPosition

(

const glm::vec2 &

position

)

Sets the camera position.

Parameters

position

2D position (glm::vec2).

Definition at line 45 of file camera_2d.cpp.

{
    mSceneComponent->SetPosition(position);
}

SetRotation()

void rendering_engine::Camera2D::SetRotation

(

float

angleDegrees

)

Sets the camera rotation angle in degrees (counterclockwise, around Z).

Parameters

angleDegrees

Angle in degrees.

Definition at line 50 of file camera_2d.cpp.

{
    mSceneComponent->SetRotation(angleDegrees);
}

SetViewportSize()

void rendering_engine::Camera2D::SetViewportSize	(	float	width,
		float	height )

Sets the viewport dimensions used to compute the projection matrix.

This defines the visible area of the camera in screen-space units. The projection matrix will be recomputed based on these dimensions.

Parameters

width	Viewport width in pixels or world units.
height	Viewport height in pixels or world units.

Definition at line 25 of file camera_2d.cpp.

{
    mViewportSize = { width, height };
}

SetZoom()

void rendering_engine::Camera2D::SetZoom

(

float

zoom

)

Sets the camera zoom (uniform scale).

Parameters

zoom	Zoom factor (1.0 = no zoom).

Definition at line 55 of file camera_2d.cpp.

{
    mSceneComponent->SetScale(glm::vec2(zoom, zoom));
}

Update()

void rendering_engine::Camera2D::Update ( float deltaTime )

virtual

Updates the camera logic (no-op for now).

Parameters

deltaTime

Time since last update (seconds).

Definition at line 21 of file camera_2d.cpp.

{
}

Member Data Documentation

mApp

IApplication& rendering_engine::Camera2D::mApp

protected

Definition at line 135 of file camera_2d.hpp.

mSceneComponent

std::unique_ptr<SceneComponent2D> rendering_engine::Camera2D::mSceneComponent

protected

Definition at line 136 of file camera_2d.hpp.

mViewportSize

glm::vec2 rendering_engine::Camera2D::mViewportSize

protected

Definition at line 137 of file camera_2d.hpp.

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

• camera_2d.hpp
• camera_2d.cpp