Ogre::ShadowCaster Class Reference
[Scene]

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

#include <OgreShadowCaster.h>

Inheritance diagram for Ogre::ShadowCaster:

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Public Types
typedef vector < ShadowRenderable * >::type	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 bool	hasEdgeList (void)=0
	Returns whether the object has a valid edge list.
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
static void	extrudeVertices (const 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 method 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, const 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 116 of file OgreShadowCaster.h.

Member Typedef Documentation

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

Definition at line 135 of file OgreShadowCaster.h.

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

Definition at line 136 of file OgreShadowCaster.h.

Constructor & Destructor Documentation

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

Definition at line 119 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

static void Ogre::ShadowCaster::extrudeVertices	(	const 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 homogeneous (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, i.e. 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,
		const 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, and Ogre::TerrainQuadTreeNode::Movable.

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::ManualObject, Ogre::MovableObject, and Ogre::StaticGeometry::Region.

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

Helper method 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