Class TMFFloat

DescriptionHierarchyFieldsMethodsProperties

Unit

Declaration

type TMFFloat = class(TX3DSimpleMultField)

Description

no description available, TX3DSimpleMultField description follows

Field holding multiple values. Remember that such field may always have any number of items, including zero.

Note that we keep MF fields contents in TFPSList or TCastleStringList instances (RawItems in this class, also accessible as Items (with more concrete class) in descendants). This means that they are in compact form, easy for reading, or even for feeding the list into OpenGL. That's the main reason why I did not simply implement TX3DSimpleMultField as a descendant of TX3DSingleFieldsList: A long list of vertexes, MFVec3f, would be kept as a list of pointers to a lot of TSFVec3f instances. This would be quite memory-consuming, and very uncomfortable for access. On the contrary, current implementation keeps all these vertexes inside one TVector3SingleList instance, that internally keeps all items in one continuos piece of memory.

Descendants implementors notes: to make new descendant:

  • In CreateUndefined you have to initialize FItemClass and create RawItems. In destructor of this class, RawItems are freed, so don't worry about this.

  • Override RawItemsAdd.

  • If your ItemClass doesn't work 100% correctly when it's initialized by CreateUndefined, you may have to override CreateItemBeforeParse. Fortunately, VRML specification was careful to choose as multi-valued field types' only fields that can behave nicely when initialized by CreateUndefined (and in fact VRML 2.0 removed the "bad fields" entirely).

  • Not strictly required, but usually it's comfortable to have a constructor that allows you to init default field value from some "array of TXxx".

Hierarchy

Overview

Methods

Public procedure RawItemsAdd(Item: TX3DSingleField); override;
Public constructor Create(AParentNode: TX3DFileItem; const AName: string; const InitialContent: array of Single);
Public constructor CreateUndefined(AParentNode: TX3DFileItem; const AName: string; const AExposed: boolean); override;
Public function EqualsDefaultValue: boolean; override;
Public function Equals(SecondValue: TX3DField; const EqualityEpsilon: Double): boolean; override;
Public procedure AssignLerp(const A: Double; Value1, Value2: TX3DField); override;
Public function CanAssignLerp: boolean; override;
Public procedure Assign(Source: TPersistent); override;
Public procedure AssignValue(Source: TX3DField); override;
Public procedure AssignDefaultValueFromValue; override;
Public class function TypeName: string; override;
Public procedure Send(const AValue: array of Single); overload;

Properties

Public property Angle: boolean read FAngle write FAngle default false;
Public property Items: TSingleList read GetItems write SetItems;
Public property ItemsSafe[Index:Integer]: Single read GetItemsSafe write SetItemsSafe;

Description

Methods

Public procedure RawItemsAdd(Item: TX3DSingleField); override;
 
Public constructor Create(AParentNode: TX3DFileItem; const AName: string; const InitialContent: array of Single);
 
Public constructor CreateUndefined(AParentNode: TX3DFileItem; const AName: string; const AExposed: boolean); override;
 
Public function EqualsDefaultValue: boolean; override;
 
Public function Equals(SecondValue: TX3DField; const EqualityEpsilon: Double): boolean; override;
 
Public procedure AssignLerp(const A: Double; Value1, Value2: TX3DField); override;
 
Public function CanAssignLerp: boolean; override;
 
Public procedure Assign(Source: TPersistent); override;
 
Public procedure AssignValue(Source: TX3DField); override;
 
Public procedure AssignDefaultValueFromValue; override;
 
Public class function TypeName: string; override;
 
Public procedure Send(const AValue: array of Single); overload;
 

Properties

Public property Angle: boolean read FAngle write FAngle default false;

Value represents an angle. When reading from X3D 3.3 file, we will make sure it's expressed in radians, honoring optional "UNIT angle ..." declaration in X3D file.

Public property Items: TSingleList read GetItems write SetItems;
 
Public property ItemsSafe[Index:Integer]: Single read GetItemsSafe write SetItemsSafe;

Access Items[] checking for range errors. In case of errors, Get will return zero, Set will do nothing, and both will produce clear OnWarning.


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