Class TShapeTree

Unit

Declaration

type TShapeTree = class(TObject)

Description

Tree of shapes.

Although VRML/X3D model already provides the tree (graph of VRML/X3D nodes), it's a little too complicated to be used at each render call. It's especially true for VRML <= 1.0 (where properties may "leak out" from one node to the next), VRML/X3D >= 2.0 cleaned a lot here but still some work must be done when traversing (like accumulating transformations).

So we process VRML/X3D tree to this tree, which is much simpler with all the geometry nodes (TAbstractGeometryNode) along with their state (TX3DGraphTraverseState) as leafs (TShape).

Hierarchy

  • TObject
  • TShapeTree

Overview

Methods

Public constructor Create(const AParentScene: TX3DEventsEngine);
Public destructor Destroy; override;
Public function MaxShapesCount: Integer;
Public procedure Traverse(const Func: TShapeTraverseFunc; const OnlyActive: boolean; const OnlyVisible: boolean = false; const OnlyCollidable: boolean = false);
Public function TraverseList( const OnlyActive: boolean; const OnlyVisible: boolean = false; const OnlyCollidable: boolean = false): TShapeList;
Public function ShapesCount(const OnlyActive: boolean; const OnlyVisible: boolean = false; const OnlyCollidable: boolean = false): Cardinal;
Public function FindGeometryNodeName(const GeometryNodeName: string; OnlyActive: boolean = false): TShape;
Public function FindShapeWithParentNamed(const ParentNodeName: string; OnlyActive: boolean = false): TShape;
Public function EnumerateTextures(const Enumerate: TEnumerateShapeTexturesFunction): Pointer; virtual; abstract;
Public function DebugInfo(const Indent: string = ''): string; virtual; abstract;
Public procedure AssociateNode(const Node: TX3DNode);
Public procedure UnAssociateNode(const Node: TX3DNode);
Public class function AssociatedShape(const Node: TX3DNode; const Index: Integer): TShapeTree; static;
Public class function AssociatedShapesCount(const Node: TX3DNode): Integer; static;
Public procedure FastTransformUpdate(var AnythingChanged: Boolean); virtual;

Properties

Public property ParentScene: TX3DEventsEngine read FParentScene write FParentScene;

Description

Methods

Public constructor Create(const AParentScene: TX3DEventsEngine);
 
Public destructor Destroy; override;
 
Public function MaxShapesCount: Integer;

Maximum value of ShapesCount. This is cached, so it's usually instant, in contrast to ShapesCount.

Public procedure Traverse(const Func: TShapeTraverseFunc; const OnlyActive: boolean; const OnlyVisible: boolean = false; const OnlyCollidable: boolean = false);

Traverse shapes inside. There are a few alternative ways to do this:

- Use this method, and have a callback called for each TShape.

- Use TraverseList, and have a list of TShape.

- Use TShapeTreeIterator.Create, that has it's own GetNext / Current methods to enumerate. This is no longer advised – using TraverseList is simpler and equally fast.

- Use TShapeList.Create(Tree, OnlyActive, OnlyVisible, OnlyCollidable) overload. This is no longer advised – using TraverseList is simpler and faster.

Public function TraverseList( const OnlyActive: boolean; const OnlyVisible: boolean = false; const OnlyCollidable: boolean = false): TShapeList;

Return TShapeList containing the traversed shapes, just like Traverse. Caller should never free the resulting list, it is owned by this TShapeTree instance.

Public function ShapesCount(const OnlyActive: boolean; const OnlyVisible: boolean = false; const OnlyCollidable: boolean = false): Cardinal;

How many shapes would be enumerated by Traverse.

Public function FindGeometryNodeName(const GeometryNodeName: string; OnlyActive: boolean = false): TShape;

Look for shape with Geometry.X3DName = GeometryNodeName. Returns Nil if not found.

Public function FindShapeWithParentNamed(const ParentNodeName: string; OnlyActive: boolean = false): TShape;

Look for shape with Geometry that has a parent named ParentNodeName. Parent is searched by Geometry.TryFindParentNodeByName. Returns Nil if not found.

Public function EnumerateTextures(const Enumerate: TEnumerateShapeTexturesFunction): Pointer; virtual; abstract;

Enumerate all single texture nodes (possibly) used by the shapes. This looks into all shapes (not only active, so e.g. it looks into all Switch/LOD children, not only the chosen one). This checks all possible ways how a texture may be used by a shape, so it looks at material fields, shaders (ComposedShader, CommonSurfaceShader) and more.

If Enumerate callbacks returns non-nil for some texture, returns it immediately, and stops further processing.

Public function DebugInfo(const Indent: string = ''): string; virtual; abstract;
 
Public procedure AssociateNode(const Node: TX3DNode);

Using the TX3DNode.InternalSceneShape field, you can associate X3D node with a number of TShapeTree instances. This allows to map X3D node -> TShapeTree instances instantly (without e.g. searching the shapes tree for it), which is great to do some operations very quickly.

Right now: - TShapeTreeTransform is associated with ITransformNode (like TTransformNode, TBillboardNode).

- TShape is associated with TShapeNode, TAbstractGeometryNode, TCoordinateNode (anything that can be inside TAbstractGeometryNode.CoordField), TNormalNode (anything that can be inside TAbstractGeometryNode.CoordField), TColorNode, TColorRGBANode (anything that can be inside TAbstractGeometryNode.ColorField), TMaterialNode (anything that can be in TShapeNode.Material), TTextureCoordinateNode and other stuff that can be inside TAbstractGeometryNode.InternalTexCoord, TClipPlaneNode .

Note that UnAssociateNode should only be called on nodes with which we are associated. Trying to call UnAssociateNode on a node on which we didn't call AssociateNode will have undefined results (for speed).

It is valid to associate X3D node with TShapeTree multiple times, but it must be unassociated the same number of times.

Parameters
Node
The node with possibly associated shapes. Never Nil.
Public procedure UnAssociateNode(const Node: TX3DNode);
 
Public class function AssociatedShape(const Node: TX3DNode; const Index: Integer): TShapeTree; static;
 
Public class function AssociatedShapesCount(const Node: TX3DNode): Integer; static;
 
Public procedure FastTransformUpdate(var AnythingChanged: Boolean); virtual;
 

Properties

Public property ParentScene: TX3DEventsEngine read FParentScene write FParentScene;

Parent TCastleSceneCore instance. This cannot be declared here as TCastleSceneCore (this would create circular unit dependency), but it always is TCastleSceneCore.


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