BufferMesh::PrimitiveGroup Class Reference
[XEngineUtil Library]

List of all members.

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Detailed Description

This class represents a primitive group. Primitive groups describe primitives, such as points, lines, or triangles, stored in a way defined by RenderContext::PrimitiveType, such as triangle list, line strip, or point list.

There are two flavours of primitive groups:

• Primitive groups that only reference vertex buffer streams and do not use an index buffer. These groups are called non-indexed primtive groups.
• Primitive groups that reference vertex buffers and an index buffer. These groups are called indexed primitive groups. Note that indexed point lists are not supported.

The PrimitiveGroup class by itself is rather useless. Only in combination with the SubMesh class does a primitive group get a meaning because a sub mesh object stores pointers to the vertex and index buffers that a primtive group uses.

The primitive group class stores the following properties about a group of primitives:

• The type of the primitive group. That is, whether it is an indexed primitive group using an index buffer or whether it is non-indexed and only requires a vertex buffer stream mapping.
• The primitive type, i.e. triangle list, point list, etc.
• The start index into the index buffer (for indexed primitive groups) or the vertex buffer streams (for non-indexed primitive groups).
• A pointer to a StateSet which is used to render the primitive group. This state set can be considered to be the "material" of this primitive group. Note that when a PrimitiveGroup object is copied, for example with the copy constructor, it still points to the same state set.
• For indexed primitives, the minimum and maximum vertex index into the vertex buffer streams that is used by this primitive group. These can both be set to 0 to indicate that all indices will be used at the possible loss of some performance if this is not the case.

Public Types
enum	PrimitiveGroupType { Indexed, NonIndexed }
	The primitive group type enum. More...
Public Member Functions
	PrimitiveGroup (PrimitiveGroupType type, RenderContext::PrimitiveType primitiveType, size_t startIndex, size_t primitiveCount, const boost::shared_ptr< StateSet > &pStateSet, size_t minVertexIndex=0, size_t maxVertexIndex=0)
	Constructor that takes a state set that will be associated with this primitive group.
	PrimitiveGroup (PrimitiveGroupType type, RenderContext::PrimitiveType primitiveType, size_t startIndex, size_t primitiveCount, size_t minVertexIndex=0, size_t maxVertexIndex=0)
	Constructor that doesn't associate a state set with this primitive group.
PrimitiveGroupType	GetType () const
	Returns the type of this primitive group, whether it is indexed or non-indexed.
RenderContext::PrimitiveType	GetPrimitiveType () const
	Returns the primitive type of this primitive group (i.e. triangle list, triangle strip, ...).
size_t	GetPrimitiveCount () const
	Returns the primitive count.
size_t	GetVertexCount () const
	Returns the number of vertices that this primitive uses.
size_t	GetStartIndex () const
	Returns the start index into the vertex buffer for non-indexed primitives and into the index buffer for indexed primitives.
const boost::shared_ptr< StateSet > &	GetStateSet () const
	Returns the state set associated with this primitive group.
size_t	GetMinVertexIndex () const
	Returns the minimum vertex index in the vertex buffer used by this primitive group, if it is an indexed primitive group.
size_t	GetMaxVertexIndex () const
	Returns the maximum vertex index in the vertex buffer used by this primitive group, if it is an indexed primitive group.

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Member Enumeration Documentation

enum PrimitiveGroupType

This enum type defines the two types of primitive groups, indexed and non-indexed. Enumeration values: Indexed  Indexed primitive group. NonIndexed  Not indexed primitive group.

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Constructor & Destructor Documentation

PrimitiveGroup (  PrimitiveGroupType  type, RenderContext::PrimitiveType  primitiveType, size_t  startIndex, size_t  primitiveCount, const boost::shared_ptr< StateSet > &  pStateSet, size_t  minVertexIndex = 0, size_t  maxVertexIndex = 0 )

Constructs a new primitive group with the given parameters. Parameters: type  The primitive group type, either Indexed or NonIndexed. primitiveType  The primitive type (points, lines or triangles). startIndex  For indexed primitive groups, the start offset into the index buffer where the primitives are supposed to begin. For non-indexed primitive groups, the start offset into the vertex buffer. primitiveCount  The number of primitive elements that make up the primitive group. pStateSet  The state set that is supposed to be associated with this primitive group. minVertexIndex  The minimum vertex index occuring in the index buffer. If you specify this, be sure that it really is the minimum vertex index used. If specified, optimizes performance because the vertex buffer will only have to be accessed starting with the vertex indexed by minVertexIndex. maxVertexIndex  The maximum vertex index occuring in the index buffer If this value is 0, then the maximum possible vertex index (which corresponds to the size of the vertex buffer - 1) will be used. Warning: The primitive type PointList is not allowed for indexed primitives.

PrimitiveGroup (  PrimitiveGroupType  type, RenderContext::PrimitiveType  primitiveType, size_t  startIndex, size_t  primitiveCount, size_t  minVertexIndex = 0, size_t  maxVertexIndex = 0 )

Constructs a new primitive group with the given parameters. This constructor does not associate a state set with the primitive group and thus creates a primitive group that doesn't change any state when rendered. Parameters: type  The primitive group type, either Indexed or NonIndexed. primitiveType  The primitive type (points, lines or triangles). startIndex  For indexed primitive groups, the start offset into the index buffer where the primitives are supposed to begin. For non-indexed primitive groups, the start offset into the vertex buffer. primitiveCount  The number of primitive elements that make up the primitive group. minVertexIndex  The minimum vertex index occuring in the index buffer. If you specify this, be sure that it really is the minimum vertex index used. If specified, optimizes performance because the vertex buffer will only have to be accessed starting with the vertex indexed by minVertexIndex. maxVertexIndex  The maximum vertex index occuring in the index buffer If this value is 0, then the maximum possible vertex index (which corresponds to the size of the vertex buffer - 1) will be used. Warning: The primitive type PointList is not allowed for indexed primitives.

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Member Function Documentation

size_t GetMaxVertexIndex (   )  const

Returns the maximum vertex index in the vertex buffer used by this primitive group, if it is an indexed primitive group.

size_t GetMinVertexIndex (   )  const

Returns the minimum vertex index in the vertex buffer used by this primitive group, if it is an indexed primitive group.

size_t GetPrimitiveCount (   )  const

Returns the primitive count.

RenderContext::PrimitiveType GetPrimitiveType (   )  const

Returns the primitive type of this primitive group (i.e. triangle list, triangle strip, ...).

size_t GetStartIndex (   )  const

Returns the start index into the vertex buffer for non-indexed primitives and into the index buffer for indexed primitives.

const boost::shared_ptr< StateSet > & GetStateSet (   )  const

Returns the state set associated with this primitive group.

BufferMesh::PrimitiveGroup::PrimitiveGroupType GetType (   )  const

Returns the type of this primitive group, whether it is indexed or non-indexed.

size_t GetVertexCount (   )  const

Returns the number of vertices that this primitive group uses. Uses the stored primitive count and primitive type to determine the number of vertices used by this primitive group.

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

• XBufferMesh.h
• XBufferMesh.cpp
• XBufferMesh.inl

 

Created with doxygen on: Thu Jan 6 14:12:16 2005 Copyright © by Martin Ecker