Class TAbstractPositionalLightNode
Unit
X3DNodes
Declaration
type TAbstractPositionalLightNode = class(TAbstractLightNode)
Description
Base class for all positional lights.
Hierarchy
Overview
Methods
Properties
Description
Methods
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procedure CreateNode; override; |
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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).
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function CalculateAttenuation(const DistanceToLight: Single): Single; overload; |
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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.
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function HasRadius: boolean; virtual; |
Should the "radius" field be taken into account.
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procedure UpdateLightInstance(var LightInstance: TLightInstance); override; |
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function PositionAndDirection: TVector4; override; |
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Properties
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property FdAttenuation: TSFVec3f read FFdAttenuation; |
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property Attenuation: TVector3 read GetAttenuation write SetAttenuation; |
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property FdLocation: TSFVec3f read FFdLocation; |
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property Location: TVector3 read GetLocation write SetLocation; |
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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.
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property FdRadius: TSFFloat read FFdRadius; |
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property Radius: Single read GetRadius write SetRadius; |
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