Class TAbstractPositionalLightNode

Unit

Declaration

type TAbstractPositionalLightNode = class(TAbstractPunctualLightNode)

Description

Base class for all positional lights.

Hierarchy

Overview

Methods

Public constructor Create(const AX3DName: string = ''; const ABaseUrl: string = ''); override;
Public function DistanceNeededForAttenuation: boolean;
Public function CalculateAttenuation(const DistanceToLight: Single): Single; overload;
Public function HasAttenuation: boolean;
Public function HasRadius: boolean; virtual;
Public procedure UpdateLightInstance(var LightInstance: TLightInstance); override;
Public function PositionAndDirection: TVector4; override;
Public procedure CreateNode; override;
Public class function ClassX3DType: string; override;

Properties

Public property SceneLocation: TVector3 read GetSceneLocation write SetSceneLocation;
Public property FdAttenuation: TSFVec3f read FFdAttenuation;
Public property Attenuation: TVector3 read GetAttenuation write SetAttenuation;
Public property FdLocation: TSFVec3f read FFdLocation;
Public property Location: TVector3 read GetLocation write SetLocation;
Public property FdRadius: TSFFloat read FFdRadius;
Public property Radius: Single read GetRadius write SetRadius;

Description

Methods

Public constructor Create(const AX3DName: string = ''; const ABaseUrl: string = ''); override;

This item has no description. Showing description inherited from TX3DNode.Create.

Constructor. Initializes various properties:

  • Name, BaseUrl are initialized from given parameters.

  • The Fields, Events lists are filled in every descendant, to have all the fields/events defined by the specification.

  • DefaultContainerField, and other node-specific stuff, is filled in descendants. This is actually implemented in CreateNode, that is called at the end of this constructor.

Public function DistanceNeededForAttenuation: boolean;

Calculate light intensity drop because of the distance to the light. This follows the equation 1/max( attenuation[0] + ... ) from the VRML/X3D specification, it is the same as OpenGL attenuation.

Since calculating the DistanceToLight for the Attenuation method may be time-consuming in some situations, you can check DistanceNeededForAttenuation first. When the DistanceNeededForAttenuation returns False, then the value of DistanceToLight parameter is ignored (you can pass anything).

The DistanceToLight should be a distance in the light source local coordinate system. TODO: although our renderers currently ignore this: ray-tracer uses global coord system, OpenGL (fixed-function and shader) renderer uses eye coord system (should be equal to global coord system for normal cameras).

Public function CalculateAttenuation(const DistanceToLight: Single): Single; overload;

This item has no description.

Public function HasAttenuation: boolean;

Is attenuation relevant. When False, you know that Attenuation function always returns 1, so there's no point in using it at all.

Public function HasRadius: boolean; virtual;

Should the "radius" field be taken into account.

Public procedure UpdateLightInstance(var LightInstance: TLightInstance); override;

This item has no description. Showing description inherited from TAbstractLightNode.UpdateLightInstance.

Update TLightInstance record when lighting location/direction (and other properties precalculated on TLightInstance) change. Assumes that LightInstance.Node = Self.

Public function PositionAndDirection: TVector4; override;

This item has no description. Showing description inherited from TAbstractPunctualLightNode.PositionAndDirection.

Position and direction expressed in homogeneous coordinates. For positional lights, the last component is always 1. For directional lights, the last component is always 0.

Note that this is expressed in the local light node coordinate system.

Public procedure CreateNode; override;

This item has no description. Showing description inherited from TAbstractChildNode.CreateNode.

Automatically generated node properties.

Do not edit this file manually! To add new properties: - add them to the text files in tools/internal/x3d-nodes-to-pascal/nodes-specification/ , - and regenerate include files by running x3d-nodes-to-pascal

Public class function ClassX3DType: string; override;

This item has no description. Showing description inherited from TX3DNode.ClassX3DType.

Node type name in VRML/X3D, for this class. Normal VRML/X3D node classes should override this to return something non-empty, and then X3DType automatically will return the same value.

Empty for classes that don't have a hardcoded VRML/X3D node name, like a special TX3DUnknownNode. Such special classes should override then X3DType to return actual non-empty name there.

You usually should call X3DType. The only use of this method is that it works on classes (it's "class function"), without needing at actual instance.

Properties

Public property SceneLocation: TVector3 read GetSceneLocation write SetSceneLocation;

Light location, expressed in scene (current TCastleScene) coordinates. Do not use this if the light node may be instantiated multiple times in the scene. The same warning as for Transform applies also here.

Public property FdAttenuation: TSFVec3f read FFdAttenuation;

Internal wrapper for property Attenuation. This wrapper API may change, we advise to access simpler Attenuation instead.

Public property Attenuation: TVector3 read GetAttenuation write SetAttenuation;

This item has no description.

Public property FdLocation: TSFVec3f read FFdLocation;

Internal wrapper for property Location. This wrapper API may change, we advise to access simpler Location instead.

Public property Location: TVector3 read GetLocation write SetLocation;

This item has no description.

Public property FdRadius: TSFFloat read FFdRadius;

Internal wrapper for property Radius. This wrapper API may change, we advise to access simpler Radius instead.

Public property Radius: Single read GetRadius write SetRadius;

This item has no description.


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