nCine::SceneNode class
#include <nCine/Graphics/SceneNode.h>

Base node of the scene graph transformation hierarchy.

Every drawable and grouping object derives from this class. A node owns a relative transform (position, anchor, scale, rotation), a color and a rendering layer, and keeps a list of child nodes. During a viewport visit the absolute transform is computed from the parent's, and the node and its children are drawn in layer and visit order.

Base classes

class Object: Base class of all nCine objects.

Derived classes

class Jazz2::Rendering::BlurRenderPass: Applies blur to a scene.
class Jazz2::Rendering::CombineRenderer: Combines all previous passes of a scene into a resulting image.
class Jazz2::Rendering::LightingRenderer: Processes all lights in a scene into an intermediate target.
class Jazz2::Rendering::UpscaleRenderPass: Upscales input image usually to a native resolution.
class Jazz2::Rendering::UpscaleRenderPass::AntialiasingSubpass: Optional antialiasing subpass.
class Jazz2::Tiles::TileMap: Represents a renderable tile map, consists of multiple layers.
class Jazz2::UI::Canvas: Canvas.
class DrawableNode: Base class for scene nodes that can be drawn through the render queue.
class ParticleSystem: Scene node that emits and simulates a pool of textured particles.

Public types

enum class VisitOrderState { Disabled, Enabled, SameAsParent }: Whether a node uses its visit order to break ties between same-layer siblings.

Public static functions

static auto sType() -> ObjectType

Constructors, destructors, conversion operators

SceneNode(SceneNode* parent, float x, float y): Constructs a node with a parent and a relative position given as two coordinates.
SceneNode(SceneNode* parent, Vector2f position): Constructs a node with a parent and a relative position given as a vector.
SceneNode(SceneNode* parent) explicit: Constructs a node with a parent, positioned at the relative origin.
SceneNode(): Constructs a node with no parent, positioned at the origin.
~SceneNode() override
SceneNode(SceneNode&& other) noexcept
SceneNode(const SceneNode& other) protected: Protected copy constructor used to clone objects.

Public functions

auto operator=(const SceneNode&) -> SceneNode& deleted
auto operator=(SceneNode&& other) -> SceneNode& noexcept
auto clone() const -> SceneNode: Returns a copy of this object.
auto parent() const -> const SceneNode*: Returns the parent node as constant, or nullptr if there is none.
auto parent() -> SceneNode*: Returns the parent node, or nullptr if there is none.
auto setParent(SceneNode* parentNode) -> bool: Sets the parent node.
auto children() -> const SmallVectorImpl<SceneNode*>&: Returns the array of child nodes.
auto children() const -> const SmallVectorImpl<const SceneNode*>&: Returns the array of child nodes as constant.
auto addChildNode(SceneNode* childNode) -> bool: Adds a node as a child of this one.
auto removeChildNode(SceneNode* childNode) -> bool: Removes a child of this node without reparenting its children.
auto removeChildNodeAt(std::uint32_t index) -> bool: Removes the child at the specified index without reparenting its children.
auto removeAllChildrenNodes() -> bool: Removes all children without reparenting their children.
auto unlinkChildNode(SceneNode* childNode) -> bool: Removes a child of this node, reparenting its children to this node.
auto childOrderIndex() const -> std::uint32_t: Returns the order index of this node among its siblings, or zero if it has no parent.
auto swapChildrenNodes(std::uint32_t firstIndex, std::uint32_t secondIndex) -> bool: Swaps two children at the specified indices.
auto swapNodeForward() -> bool: Moves this node one position forward in the parent's list of children.
auto swapNodeBack() -> bool: Moves this node one position back in the parent's list of children.
auto visitOrderState() const -> enum VisitOrderState: Returns the node visit order state.
void setVisitOrderState(enum VisitOrderState visitOrderState): Sets the node visit order state.
auto visitOrderIndex() const -> std::uint16_t: Returns the visit drawing order index of the node.
void OnUpdate(float timeMult) virtual: Called every frame to update the node state.
void OnVisit(RenderQueue& renderQueue, std::uint32_t& visitOrderIndex) virtual: Updates the absolute transform, draws the node and visits its children.
auto OnDraw(RenderQueue& renderQueue) -> bool virtual: Called when the node needs to be drawn, returning true if a command was added.
auto isUpdateEnabled() const -> bool: Returns true if node updating is enabled.
void setUpdateEnabled(bool updateEnabled): Enables or disables node updating.
auto isDrawEnabled() const -> bool: Returns true if node drawing is enabled.
void setDrawEnabled(bool drawEnabled): Enables or disables node drawing.
auto isEnabled() const -> bool: Returns true if the node is both updating and drawing.
void setEnabled(bool isEnabled): Enables or disables both node updating and drawing.
auto position() const -> Vector2f: Returns the node position relative to its parent.
auto absPosition() const -> Vector2f: Returns the absolute node position.
void setPosition(float x, float y): Sets the node position through two coordinates.
void setPosition(Vector2f position): Sets the node position through a vector.
void setPositionX(float x): Sets the X coordinate of the node position.
void setPositionY(float y): Sets the Y coordinate of the node position.
void move(float x, float y): Moves the node by two offsets.
void move(Vector2f position): Moves the node by an offset vector.
void moveX(float x): Moves the node by an offset on the X axis.
void moveY(float y): Moves the node by an offset on the Y axis.
auto absAnchorPoint() const -> Vector2f: Returns the transformation anchor point in pixels.
void setAbsAnchorPoint(float x, float y): Sets the transformation anchor point in pixels through two coordinates.
void setAbsAnchorPoint(Vector2f point): Sets the transformation anchor point in pixels through a Vector2f.
auto scale() const -> const Vector2f&: Returns the node scale factors.
auto absScale() const -> const Vector2f&: Returns the absolute node scale factors.
void setScale(float scaleFactor): Sets a uniform scale factor for both axes.
void setScale(float scaleFactorX, float scaleFactorY): Sets the horizontal and vertical scale factors separately.
void setScale(Vector2f scaleFactor): Sets the horizontal and vertical scale factors through a Vector2f.
auto rotation() const -> float: Returns the node rotation in radians.
auto absRotation() const -> float: Returns the absolute node rotation in radians.
void setRotation(float rotation): Sets the node rotation in radians.
auto color() const -> Colorf: Returns the node color.
auto absColor() const -> Colorf: Returns the absolute node color.
void setColor(const Color& color): Sets the node color through a Color object.
void setColor(const Colorf& color): Sets the node color through a Colorf object.
auto alpha() const -> float: Returns the node alpha.
auto absAlpha() const -> float: Returns the absolute node alpha.
void setAlpha(std::uint8_t alpha): Sets the node alpha through an unsigned char component.
void setAlphaF(float alpha): Sets the node alpha through a float component.
auto layer() const -> std::uint16_t: Returns the node rendering layer.
auto absLayer() const -> std::uint16_t: Returns the absolute node rendering layer.
void setLayer(std::uint16_t layer): Sets the node rendering layer.
auto worldMatrix() const -> const Matrix4x4f&: Returns the node world matrix.
void setWorldMatrix(const Matrix4x4f& worldMatrix): Sets the node world matrix (only useful when called inside OnPostUpdate()).
auto localMatrix() const -> const Matrix4x4f&: Returns the node local matrix.
void setLocalMatrix(const Matrix4x4f& localMatrix): Sets the node local matrix.
auto deleteChildrenOnDestruction() const -> bool: Returns the delete children on destruction flag.
void setDeleteChildrenOnDestruction(bool shouldDeleteChildrenOnDestruction): Sets the delete children on destruction flag.
auto lastFrameUpdated() const -> std::uint32_t: Returns the last frame in which any viewport updated this node.

Protected types

enum DirtyBitPositions { TransformationBit = 0, ColorBit = 1, SizeBit = 2, TextureBit = 3, AabbBit = 4, TransformationUploadBit = 5, ColorUploadBit = 6 }: Bit positions inside the dirty bitset.

Protected functions

void swapChildPointer(SceneNode* first, SceneNode* second): Swaps the child pointer of a parent when moving an object.
void transform() virtual

Protected variables

SceneNode* parent_: Pointer to the parent node.
SmallVector<SceneNode*, 0> children_: Array of child nodes.
std::uint32_t childOrderIndex_: Order index of this node among its siblings.
bool updateEnabled_
bool drawEnabled_
bool withVisitOrder_: Whether the visit order resolves the drawing order of same-layer nodes.
bool shouldDeleteChildrenOnDestruction_: Whether the destructor should also delete all children.
enum VisitOrderState visitOrderState_: Visit order state of this node.
std::uint16_t visitOrderIndex_: Visit order index of this node.
std::uint16_t layer_: Node rendering layer.
Vector2f position_: Node position relative to its parent.
Vector2f anchorPoint_: Anchor point for transformations, in pixels.
Vector2f scaleFactor_: Horizontal and vertical scale factors for the node size.
float rotation_: Clockwise node rotation in radians.
Colorf color_: Node color for transparency and translucency.
Vector2f absPosition_: Absolute position as calculated by the transform() function.
Vector2f absScaleFactor_: Absolute horizontal and vertical scale factors as calculated by the transform() function.
float absRotation_: Absolute node rotation as calculated by the transform() function.
Colorf absColor_: Absolute node color as calculated by the transform() function.
std::uint16_t absLayer_: Absolute node rendering layer as calculated by the transform() function.
BitSet<std::uint8_t> dirtyBits_: Bitset that stores the various dirty state bits.
Matrix4x4f worldMatrix_: World transformation matrix (calculated from the local and the parent's world matrix).
Matrix4x4f localMatrix_: Local transformation matrix.
std::uint32_t lastFrameUpdated_: Last frame any viewport updated this node.

Constants

static float MinRotation constexpr: Minimum amount of rotation that triggers a sine and cosine recalculation.

Function documentation

std::uint16_t nCine::SceneNode::absLayer() const

Returns the absolute node rendering layer.

void nCine::SceneNode::setLayer(std::uint16_t layer)

Sets the node rendering layer.

bool nCine::SceneNode::deleteChildrenOnDestruction() const

Returns the delete children on destruction flag.

When the flag is true the children are deleted upon node destruction.

Variable documentation

std::uint32_t nCine::SceneNode::childOrderIndex_ protected

Order index of this node among its siblings.

bool nCine::SceneNode::withVisitOrder_ protected

Whether the visit order resolves the drawing order of same-layer nodes.

std::uint16_t nCine::SceneNode::layer_ protected

Node rendering layer.

Even if the base scene node is not always drawable, it carries layer information to easily pass it down to its children.

Vector2f nCine::SceneNode::anchorPoint_ protected

Anchor point for transformations, in pixels.

Colorf nCine::SceneNode::color_ protected

Node color for transparency and translucency.

Even if the base scene node is not always drawable, it carries color information to easily pass it down to its children.