Represents a hierarchical 2D transform component. More...

#include <scene_component_2d.hpp>

Public Member Functions
	SceneComponent2D ()
	Constructs a SceneComponent2D with identity transform. More...

virtual	~SceneComponent2D ()=default
	Destructor. More...

void	SetPosition (const glm::vec2 &position)
	Sets the local position of this component. More...

void	SetRotation (float angleDegrees)
	Sets the rotation angle in degrees. More...

void	SetScale (const glm::vec2 &scale)
	Sets the scale in each dimension. More...

const glm::vec2 &	GetPosition () const
	Gets the current position. More...

float	GetRotation () const
	Gets the current rotation angle (in degrees). More...

const glm::vec2 &	GetScale () const
	Gets the current scale. More...

glm::vec2	GetWorldPosition () const
	Returns the world-space position of this component. More...

float	GetWorldRotation () const
	Returns the accumulated world-space rotation. More...

glm::vec2	GetWorldScale () const
	Returns the accumulated world-space scale. More...

const glm::mat4 &	GetWorldMatrix ()
	Returns the world transformation matrix. More...

void	UpdateLocalMatrix ()
	Recomputes the local transformation matrix. More...

void	UpdateWorldMatrix ()
	Recomputes the world transformation matrix. More...

void	AttachTo (SceneComponent2D *parent)
	Attaches this scene component to a parent scene component. More...

	SceneComponent2D (const SceneComponent2D &rhs)=delete

SceneComponent2D &	operator= (const SceneComponent2D &rhs)=delete

Protected Attributes
glm::vec2	mPosition

float	mRotation

glm::vec2	mScale

glm::mat4	mLocalMatrix

glm::mat4	mWorldMatrix

SceneComponent2D *	mParent

bool	bIsDirty

Detailed Description

Represents a hierarchical 2D transform component.

SceneComponent2D stores local 2D transformation state:

Position (x, y)
Rotation (degrees, counterclockwise around Z-axis)
Scale (x, y)

It supports parent-child relationships, allowing hierarchical transform propagation. When attached to a parent component, its world transform is computed as:

World = ParentWorld * Local

The engine uses a left-handed coordinate system:

X+ : Right
Y+ : Up

Transform order is:

M = T * R * S

which results in object-space vertices being scaled, then rotated, then translated when applied.

The component uses a dirty-flag mechanism. World matrices are recomputed lazily when requested.

Note

This component operates strictly in the 2D domain.
Rotation is always around the Z-axis.
Ownership and lifetime are managed externally (e.g., by Actor2D).

See also: Actor2D

Definition at line 51 of file scene_component_2d.hpp.

Constructor & Destructor Documentation

◆ SceneComponent2D() [1/2]

rendering_engine::SceneComponent2D::SceneComponent2D ( )

Constructs a SceneComponent2D with identity transform.

Initial state:

Position = (0, 0)
Rotation = 0 degrees
Scale = (1, 1)
No parent attached

Definition at line 8 of file scene_component_2d.cpp.

    :
    mPosition{ 0.0f, 0.0f },
    mRotation{ 0.0f },
    mScale{ 1.0f, 1.0f },
    mWorldMatrix{ 1.0f },
    mLocalMatrix{ 1.0f },
    mParent(nullptr),
    bIsDirty(true)
{
}

◆ ~SceneComponent2D()

virtual rendering_engine::SceneComponent2D::~SceneComponent2D ( )

virtualdefault

Destructor.

◆ SceneComponent2D() [2/2]

rendering_engine::SceneComponent2D::SceneComponent2D ( const SceneComponent2D & rhs )

delete

Member Function Documentation

◆ AttachTo()

void rendering_engine::SceneComponent2D::AttachTo ( SceneComponent2D * parent )

Attaches this scene component to a parent scene component.

After attachment, this component's transform becomes relative to the parent. The world transformation is computed by combining the parent's world transform with this component's local transform.

Passing nullptr detaches the component and makes it a root-level component.

Parameters

parent Pointer to the parent SceneComponent2D, or nullptr to detach.

Definition at line 101 of file scene_component_2d.cpp.

{
    mParent = parent;
 
    bIsDirty = true;
}

◆ GetPosition()

const glm::vec2 & rendering_engine::SceneComponent2D::GetPosition ( ) const

inline

Gets the current position.

Returns: The position as glm::vec2.

Definition at line 96 of file scene_component_2d.hpp.

96{ return mPosition; }

◆ GetRotation()

float rendering_engine::SceneComponent2D::GetRotation ( ) const

inline

Gets the current rotation angle (in degrees).

Returns: The rotation angle (degrees).

Definition at line 102 of file scene_component_2d.hpp.

102{ return mRotation; }

◆ GetScale()

const glm::vec2 & rendering_engine::SceneComponent2D::GetScale ( ) const

inline

Gets the current scale.

Returns: The scale as glm::vec2.

Definition at line 108 of file scene_component_2d.hpp.

108{ return mScale; }

◆ GetWorldMatrix()

const glm::mat4 & rendering_engine::SceneComponent2D::GetWorldMatrix ( )

Returns the world transformation matrix.

If the component is marked dirty, the world matrix will be recomputed before returning.

Returns: 4x4 world transformation matrix.

Definition at line 62 of file scene_component_2d.cpp.

{
    if (bIsDirty)
    {
        UpdateWorldMatrix();
    }
    return mWorldMatrix;
}

◆ GetWorldPosition()

glm::vec2 rendering_engine::SceneComponent2D::GetWorldPosition ( ) const

Returns the world-space position of this component.

Extracted from the world transformation matrix.

Returns: World position as glm::vec2.

Definition at line 38 of file scene_component_2d.cpp.

{
    const glm::mat4& world = const_cast<SceneComponent2D*>(this)->GetWorldMatrix();
    return glm::vec2(world[3]);
}

◆ GetWorldRotation()

float rendering_engine::SceneComponent2D::GetWorldRotation ( ) const

Returns the accumulated world-space rotation.

If attached to a parent, this includes parent rotation.

Returns: World rotation angle in degrees.

Definition at line 44 of file scene_component_2d.cpp.

{
    const glm::mat4& world = const_cast<SceneComponent2D*>(this)->GetWorldMatrix();
 
    float angle = atan2(world[1][0], world[0][0]);
    return glm::degrees(angle);
}

◆ GetWorldScale()

glm::vec2 rendering_engine::SceneComponent2D::GetWorldScale ( ) const

Returns the accumulated world-space scale.

If attached to a parent, this includes parent scaling.

Returns: World scale as glm::vec2.

Definition at line 52 of file scene_component_2d.cpp.

{
    const glm::mat4& world = const_cast<SceneComponent2D*>(this)->GetWorldMatrix();
 
    return glm::vec2(
        glm::length(glm::vec2(world[0])),
        glm::length(glm::vec2(world[1]))
    );
}

◆ operator=()

SceneComponent2D & rendering_engine::SceneComponent2D::operator= ( const SceneComponent2D & rhs )

delete

◆ SetPosition()

void rendering_engine::SceneComponent2D::SetPosition ( const glm::vec2 & position )

Sets the local position of this component.

Marks the component as dirty so that world transformation will be recalculated when needed.

Parameters

position Local position in 2D space.

Definition at line 20 of file scene_component_2d.cpp.

{
    mPosition = position;
    bIsDirty = true;
}

◆ SetRotation()

void rendering_engine::SceneComponent2D::SetRotation ( float angleDegrees )

Sets the rotation angle in degrees.

Parameters

angleDegrees Angle in degrees (counterclockwise).

Definition at line 26 of file scene_component_2d.cpp.

{
    mRotation = angleDegrees;
    bIsDirty = true;
}

◆ SetScale()

void rendering_engine::SceneComponent2D::SetScale ( const glm::vec2 & scale )

Sets the scale in each dimension.

Parameters

scale New scale as glm::vec2.

Definition at line 32 of file scene_component_2d.cpp.

{
    mScale = scale;
    bIsDirty = true;
}

◆ UpdateLocalMatrix()

void rendering_engine::SceneComponent2D::UpdateLocalMatrix ( )

Recomputes the local transformation matrix.

The local matrix is constructed as:

Local = T * R * S

This method does not compute the world matrix. Called internally by UpdateWorldMatrix().

Definition at line 71 of file scene_component_2d.cpp.

{
    if (!bIsDirty)
    {
        return;
    }
    const float r = glm::radians(mRotation);
 
    const glm::mat4 S = glm::scale(glm::mat4(1.0f), glm::vec3(mScale, 1.0f));
    const glm::mat4 R = glm::rotate(glm::mat4(1.0f), r, glm::vec3(0.0f, 0.0f, 1.0f));
    const glm::mat4 T = glm::translate(glm::mat4(1.0f), glm::vec3(mPosition, 0.0f));
 
    mLocalMatrix = T * R * S;
}

◆ UpdateWorldMatrix()

void rendering_engine::SceneComponent2D::UpdateWorldMatrix ( )

Recomputes the world transformation matrix.

Combines parent world matrix (if any) with the local matrix:

World = ParentWorld * Local

Clears the dirty flag after update.

Definition at line 86 of file scene_component_2d.cpp.

{
    UpdateLocalMatrix();
 
    if (mParent)
    {
        mWorldMatrix = mParent->GetWorldMatrix() * mLocalMatrix;
    }
    else
    {
        mWorldMatrix = mLocalMatrix;
    }
    bIsDirty = false;
}

Member Data Documentation

◆ bIsDirty

bool rendering_engine::SceneComponent2D::bIsDirty

protected

Definition at line 190 of file scene_component_2d.hpp.

◆ mLocalMatrix

glm::mat4 rendering_engine::SceneComponent2D::mLocalMatrix

protected

Definition at line 186 of file scene_component_2d.hpp.

◆ mParent

SceneComponent2D* rendering_engine::SceneComponent2D::mParent

protected

Definition at line 189 of file scene_component_2d.hpp.

◆ mPosition

glm::vec2 rendering_engine::SceneComponent2D::mPosition

protected

Definition at line 182 of file scene_component_2d.hpp.

◆ mRotation

float rendering_engine::SceneComponent2D::mRotation

protected

Definition at line 183 of file scene_component_2d.hpp.

◆ mScale

glm::vec2 rendering_engine::SceneComponent2D::mScale

protected

Definition at line 184 of file scene_component_2d.hpp.

◆ mWorldMatrix

glm::mat4 rendering_engine::SceneComponent2D::mWorldMatrix

protected

Definition at line 187 of file scene_component_2d.hpp.

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

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SceneComponent2D() [1/2]

◆ ~SceneComponent2D()

◆ SceneComponent2D() [2/2]

Member Function Documentation

◆ AttachTo()

◆ GetPosition()

◆ GetRotation()

◆ GetScale()

◆ GetWorldMatrix()

◆ GetWorldPosition()

◆ GetWorldRotation()

◆ GetWorldScale()

◆ operator=()

◆ SetPosition()

◆ SetRotation()

◆ SetScale()

◆ UpdateLocalMatrix()

◆ UpdateWorldMatrix()

Member Data Documentation

◆ bIsDirty

◆ mLocalMatrix

◆ mParent

◆ mPosition

◆ mRotation

◆ mScale

◆ mWorldMatrix