Class TAbstractLightNode
Unit
X3DNodes
Declaration
type TAbstractLightNode = class(TAbstractChildNode)
Description
Base class for all VRML / X3D light nodes.
Note that even the old VRML 1.0 light nodes inherit from this. Although they interpret some bits differently ("ambientIntensity" < 0 has special meaning). But most of the fields behave identically, they only have different default values.
Hierarchy
Overview
Methods
Properties
Description
Methods
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procedure CreateNode; override; |
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function ProjectionMatrix: TMatrix4Single; virtual; |
Matrices for rendering shadow map from this light. Identity in this class, override for subclasses able to do shadow mapping.
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function LocationLocal: TVector3Single; virtual; |
Light location, direction and up vectors. Useful for example when you think of lights as cameras (for shadow maps).
DirectionLocal must be exactly zero for PointLight (that doesn't have a direction).
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procedure Box3DDistances(const Box: TBox3D; out MinDistance, MaxDistance: Single); virtual; abstract; |
Calculate distances between the given Box and this light source. This is intended to capture the depth distances where the box resides, useful for calculating e.g. depth ranges to capture in the shadow maps. Depending on light source type, various distance measures may be used, appropriate to light sources projection.
Always MinDistance <= MaxDistance. They may be negative when we measure along the light's direction.
Exceptions raised
- EBox3DEmpty
- When used with an empty box.
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procedure UpdateLightInstanceState( var LightInstance: TLightInstance; State: TX3DGraphTraverseState); |
Update TLightInstance record when lighting State changes. Assumes that LightInstance.Node = Self.
This will set LightInstance.Transform properties, and recalculate all LightInstance properties based on Transform.
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procedure UpdateLightInstance( var LightInstance: TLightInstance); virtual; |
Update TLightInstance record when lighting location/direction (and other properties precalculated on TLightInstance) change. Assumes that LightInstance.Node = Self.
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function Scope: TLightScope; virtual; |
Light scope. Default implementation returns lsGlobal or lsLocal, depending on "global" field value (this follows VRML/X3D >= 2.0 rules).
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Properties
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property FdIntensity: TSFFloat read FFdIntensity; |
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property FdColor: TSFColor read FFdColor; |
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property FdAmbientIntensity: TSFFloat read FFdAmbientIntensity; |
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property FdGlobal: TSFBool read FFdGlobal; |
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property FdShadowVolumes: TSFBool read FFdShadowVolumes; |
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property FdShadowVolumesMain: TSFBool read FFdShadowVolumesMain; |
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property FdProjectionFar: TSFFloat read FFdProjectionFar; |
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property FdDefaultShadowMap: TSFNode read FFdDefaultShadowMap; |
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property FdShadows: TSFBool read FFdShadows; |
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property FdEffects: TMFNode read FFdEffects; |
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property Transform: TMatrix4Single read FTransform; |
Transformation of this light node. Normal lights can be instanced many times within the scene, with various transformation, so this transformation property cannot be used.
However, in special cases, you know that light node occurs only once within the scene (see [http://castle-engine.sourceforge.net/x3d_extensions.php#section_ext_shadow_maps]). Then it's useful.
It is gathered during traversing. Last BeforeTraverse call for this node sets Transform properties. By default, it represents identity transformation.
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