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Ogre::ShadowCaster Class Reference

This class defines the interface that must be implemented by shadow casters. More...

#include <OgreShadowCaster.h>

Inheritance diagram for Ogre::ShadowCaster:

Ogre::MovableObject Ogre::BillboardSet Ogre::Entity Ogre::Frustum Ogre::Light Ogre::MovablePlane Ogre::ParticleSystem Ogre::SimpleRenderable Ogre::StaticGeometry::Region Ogre::TerrainRenderable List of all members.

Public Types

typedef std::vector< ShadowRenderable * > ShadowRenderableList
typedef VectorIterator< ShadowRenderableList > ShadowRenderableListIterator

Public Member Functions

virtual ~ShadowCaster ()
virtual bool getCastShadows (void) const=0
 Returns whether or not this object currently casts a shadow.

virtual EdgeData * getEdgeList (void)=0
 Returns details of the edges which might be used to determine a silhouette.

virtual const AxisAlignedBox & getWorldBoundingBox (bool derive=false) const=0
 Get the world bounding box of the caster.

virtual const AxisAlignedBox & getLightCapBounds (void) const=0
 Gets the world space bounding box of the light cap.

virtual const AxisAlignedBox & getDarkCapBounds (const Light &light, Real dirLightExtrusionDist) const=0
 Gets the world space bounding box of the dark cap, as extruded using the light provided.

virtual ShadowRenderableListIterator getShadowVolumeRenderableIterator (ShadowTechnique shadowTechnique, const Light *light, HardwareIndexBufferSharedPtr *indexBuffer, bool extrudeVertices, Real extrusionDistance, unsigned long flags=0)=0
 Gets an iterator over the renderables required to render the shadow volume.

virtual Real getPointExtrusionDistance (const Light *l) const=0
 Get the distance to extrude for a point/spot light.


Static Public Member Functions

void extrudeVertices (HardwareVertexBufferSharedPtr vertexBuffer, size_t originalVertexCount, const Vector4 &lightPos, Real extrudeDist)
 Utility method for extruding vertices based on a light.


Protected Member Functions

Real getExtrusionDistance (const Vector3 &objectPos, const Light *light) const
 Helper moethod for calculating extrusion distance.

virtual void updateEdgeListLightFacing (EdgeData *edgeData, const Vector4 &lightPos)
 Tells the caster to perform the tasks necessary to update the edge data's light listing.

virtual void generateShadowVolume (EdgeData *edgeData, HardwareIndexBufferSharedPtr indexBuffer, const Light *light, ShadowRenderableList &shadowRenderables, unsigned long flags)
 Generates the indexes required to render a shadow volume into the index buffer which is passed in, and updates shadow renderables to use it.

virtual void extrudeBounds (AxisAlignedBox &box, const Vector4 &lightPos, Real extrudeDist) const
 Utility method for extruding a bounding box.

Detailed Description

This class defines the interface that must be implemented by shadow casters.

Definition at line 104 of file OgreShadowCaster.h.

Member Typedef Documentation

typedef std::vector<ShadowRenderable*> Ogre::ShadowCaster::ShadowRenderableList
 

Definition at line 121 of file OgreShadowCaster.h.

typedef VectorIterator<ShadowRenderableList> Ogre::ShadowCaster::ShadowRenderableListIterator
 

Definition at line 122 of file OgreShadowCaster.h.

Constructor & Destructor Documentation

virtual Ogre::ShadowCaster::~ShadowCaster (   )  [virtual]
 

Definition at line 107 of file OgreShadowCaster.h.

Member Function Documentation

virtual void Ogre::ShadowCaster::extrudeBounds (  AxisAlignedBox &  box,
const Vector4 &  lightPos,
Real  extrudeDist
)  const [protected, virtual]
 

Utility method for extruding a bounding box.

Parameters:
box Original bounding box, will be updated in-place
lightPos 4D light position in object space, when w=0.0f this represents a directional light
extrudeDist The distance to extrude

void Ogre::ShadowCaster::extrudeVertices (  HardwareVertexBufferSharedPtr  vertexBuffer,
size_t  originalVertexCount,
const Vector4 &  lightPos,
Real  extrudeDist
)  [static]
 

Utility method for extruding vertices based on a light.

Remarks:
Unfortunately, because D3D cannot handle homogenous (4D) position coordinates in the fixed-function pipeline (GL can, but we have to be cross-API), when we extrude in software we cannot extrude to infinity the way we do in the vertex program (by setting w to 0.0f). Therefore we extrude by a fixed distance, which may cause some problems with larger scenes. Luckily better hardware (ie vertex programs) can fix this.
Parameters:
vertexBuffer The vertex buffer containing ONLY xyz position values, which must be originalVertexCount * 2 * 3 floats long.
originalVertexCount The count of the original number of vertices, ie the number in the mesh, not counting the doubling which has already been done (by VertexData::prepareForShadowVolume) to provide the extruded area of the buffer.
lightPos 4D light position in object space, when w=0.0f this represents a directional light
extrudeDist The distance to extrude

virtual void Ogre::ShadowCaster::generateShadowVolume (  EdgeData *  edgeData,
HardwareIndexBufferSharedPtr  indexBuffer,
const Light *  light,
ShadowRenderableList &  shadowRenderables,
unsigned long  flags
)  [protected, virtual]
 

Generates the indexes required to render a shadow volume into the index buffer which is passed in, and updates shadow renderables to use it.

Parameters:
edgeData The edge information to use
indexBuffer The buffer into which to write data into; current contents are assumed to be discardable.
light The light, mainly for type info as silhouette calculations should already have been done in updateEdgeListLightFacing
shadowRenderables A list of shadow renderables which has already been constructed but will need populating with details of the index ranges to be used.
flags Additional controller flags, see ShadowRenderableFlags

virtual bool Ogre::ShadowCaster::getCastShadows (  void   )  const [pure virtual]
 

Returns whether or not this object currently casts a shadow.

Implemented in Ogre::MovableObject.

virtual const AxisAlignedBox& Ogre::ShadowCaster::getDarkCapBounds (  const Light &  light,
Real  dirLightExtrusionDist
)  const [pure virtual]
 

Gets the world space bounding box of the dark cap, as extruded using the light provided.

Implemented in Ogre::MovableObject.

virtual EdgeData* Ogre::ShadowCaster::getEdgeList (  void   )  [pure virtual]
 

Returns details of the edges which might be used to determine a silhouette.

Implemented in Ogre::Entity, Ogre::MovableObject, and Ogre::StaticGeometry::Region.

Real Ogre::ShadowCaster::getExtrusionDistance (  const Vector3 &  objectPos,
const Light *  light
)  const [protected]
 

Helper moethod for calculating extrusion distance.

virtual const AxisAlignedBox& Ogre::ShadowCaster::getLightCapBounds (  void   )  const [pure virtual]
 

Gets the world space bounding box of the light cap.

Implemented in Ogre::MovableObject.

virtual Real Ogre::ShadowCaster::getPointExtrusionDistance (  const Light *  l  )  const [pure virtual]
 

Get the distance to extrude for a point/spot light.

Implemented in Ogre::MovableObject.

virtual ShadowRenderableListIterator Ogre::ShadowCaster::getShadowVolumeRenderableIterator (  ShadowTechnique  shadowTechnique,
const Light *  light,
HardwareIndexBufferSharedPtr *  indexBuffer,
bool  extrudeVertices,
Real  extrusionDistance,
unsigned long  flags = 0
)  [pure virtual]
 

Gets an iterator over the renderables required to render the shadow volume.

Remarks:
Shadowable geometry should ideally be designed such that there is only one ShadowRenderable required to render the the shadow; however this is not a necessary limitation and it can be exceeded if required.
Parameters:
shadowTechnique The technique being used to generate the shadow
light The light to generate the shadow from
indexBuffer The index buffer to build the renderables into, the current contents are assumed to be disposable.
extrudeVertices If true, this means this class should extrude the vertices of the back of the volume in software. If false, it will not be done (a vertex program is assumed).
extrusionDistance The distance to extrude the shadow volume
flags Technique-specific flags, see ShadowRenderableFlags

Implemented in Ogre::Entity, Ogre::MovableObject, and Ogre::StaticGeometry::Region.

virtual const AxisAlignedBox& Ogre::ShadowCaster::getWorldBoundingBox (  bool  derive = false  )  const [pure virtual]
 

Get the world bounding box of the caster.

Implemented in Ogre::Entity, and Ogre::MovableObject.

virtual void Ogre::ShadowCaster::updateEdgeListLightFacing (  EdgeData *  edgeData,
const Vector4 &  lightPos
)  [protected, virtual]
 

Tells the caster to perform the tasks necessary to update the edge data's light listing.

Can be overridden if the subclass needs to do additional things.

Parameters:
edgeData The edge information to update
lightPos 4D vector representing the light, a directional light has w=0.0

The documentation for this class was generated from the following file:

Copyright © 2000-2005 by The OGRE Team
Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License.
Last modified Sun Feb 12 13:03:32 2006